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1.2: Science as a Way of Understanding the Natural World

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Learning Objectives

After completing this chapter, you will be able to

Describe the nature of science and its usefulness in explaining the natural world.
Distinguish among facts, hypotheses, and theories.
Outline the methodology of science, including the importance of tests designed to disprove hypotheses.
Discuss the importance of uncertainty in many scientific predictions, and the relevance of this to environmental controversies.

The Nature of Science

Science is a way of knowing about the world around us. Environmental science focuses on gaining an understanding of how the environment, with all of its biotic (living) and abiotic (non-living) components, functions as well as how humans impact it or are impacted by it. In other words, our actions may alter the environment in a way that impacts us, such as when we pollute water through our industrial activities and later discover that there are health implications that arise from being exposed to or consuming that polluted water.

The broad goals of science are to understand natural phenomena and to explain how they may be changing over time. To achieve these goals, scientists carefully observe natural phenomena and conduct experiments.

All science begins with observation , so a keen sense of awareness is the primary tool of the scientist. Some science is purely observational in nature and is often referred to as descriptive science. To learn more about how the environment functions, scientists often rely on the scientific method .

Scientific investigations may be pure or applied. Pure science is driven by intellectual curiosity – it is the unfettered search for knowledge and understanding, without regard for its usefulness in human welfare. Applied science is more goal-oriented and deals with practical difficulties and problems of one sort or another. Applied science might examine how to improve technology, or to advance the management of natural resources, or to reduce pollution or other environmental damages associated with human activities.

The Scientific Method

Most of us are already familiar with the scientific method because it closely mirrors the thought process we undergo in solving a problem. Let’s say for example that you have a coffee maker that operates on a timer and that you are used to waking up in the morning to the smell of brewed coffee. One day you awake to find that although you set the timer the night before, there is no coffee in the pot. That observation is the very first step in beginning to solve a problem and it is also the very beginning of employing the scientific method.

Next, your mind may jump to the question of why the coffee maker did not make the coffee. You may then begin to search for a solution. Here is where the scientific method slows down a bit. While you may immediately think, did I forget to put water in the coffee maker? The scientific method is going to take this step by step. The first step is going to be to develop a hypothesis , or a proposed explanation (there is no coffee because there is no water in the machine). A prediction based on the hypothesis is then generated (adding water to the coffee maker will solve the problem). And finally, this prediction is tested (add water to the coffee maker to determine if that was the problem).

The results generated by applying the scientific method are then used to refine the process and narrow down the number of possible explanations. If there was water in the coffee maker all along, and adding water did not solve the problem, then the hypothesis is not supported and a new hypothesis is proposed. If, however, adding water gets you the coffee you have been waiting for, then your hypothesis is supported and your problem solved. In the world of science, this would not be the end of the application of the scientific method, because there is always more to learn. When studying the world around us, we always strive to build large bodies of evidence so experiments are generally replicated as a means of making for more robust conclusions.

how does hypothesis help scientists understand the natural world

Facts, Hypotheses, and Experiments

A fact is an event or thing that is definitely known to have happened, to exist, and to be true. Facts are based on experience and scientific evidence. In contrast, a hypothesis is a proposed explanation for the occurrence of a phenomenon. Scientists formulate hypotheses as statements and then test them through experiments and other forms of research. Hypotheses are developed using logic, inference, and mathematical arguments in order to explain observed phenomena. However, it must always be possible to refute a scientific hypothesis. Thus, the hypothesis that “cats are so intelligent that they prevent humans from discovering it” cannot be logically refuted, and so it is not a scientific hypothesis.

A theory is a broader conception that refers to a set of explanations, rules, and laws. These are supported by a large body of observational and experimental evidence, all leading to robust conclusions. It is important to note that the term 'theory' is used differently in science than in common language. What people generally mean then they say they have a 'theory' is that they have an idea. This most closely resembles a scientific hypothesis. In science, theories are widely supported and accepted. The following are some of the most famous theories in science:

the theory of gravitation , first proposed by Isaac Newton (1642-1727)
the theory of evolution by natural selection , published simultaneously in 1858 by two English naturalists, Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913)
the theory of relativity , identified by the German–Swiss physicist, Albert Einstein (1879-1955)

Celebrated theories like these are strongly supported by large bodies of evidence, and they will likely persist for a long time. However, we cannot say that these (or any other) theories are known with certainty to be true –some future experiments may yet falsify even these famous theories. Thus, science is always considered to be provisional.

An experiment is a test or investigation that is designed to provide evidence in support of, or preferably against, a hypothesis. A natural experiment is conducted by observing actual variations of phenomena in nature, and then developing explanations by analysis of possible causal mechanisms. A manipulative experiment involves the deliberate alteration of factors that are hypothesized to influence phenomena. The manipulations are carefully planned and controlled in order to determine whether predicted responses will occur, thereby uncovering causal relationships. In a manipulative experiment, there are two types of variables. The first is the variable that is altered by the scientist in order to ascertain its effect. this is called the independent variable . The second is the variable that was measured in order to see what the effect was - the dependent variable .

By far the most useful working hypotheses in scientific research are designed to disprove rather than support. Thus, null hypotheses are often formulated to enhance our progress toward understanding a particular phenomenon. A null hypothesis is a specific testable investigation that denies something implied by the main hypothesis being studied. Unless null hypotheses are eliminated on the basis of contrary evidence, we cannot be confident of the main hypothesis.

To demonstrate this point, we will draw an example from a philosopher named Karl Popper (1902-1994). Let’s suppose that we have observed that every swan we have ever seen in nature has been white. Since we are trying to build on our scientific understanding of biodiversity, we can propose the hypothesis that ‘all swans are white’ and set about testing it. In order to validate our hypothesis, we can begin looking in all of the lakes and ponds where we would expect to see swans and take observational data, counting the number of swans and noting their color. The limitation in terms of science is that no matter how many white swans we encounter, we will never have proven that all swans are white, because we must always be open to the possibility that there is a swan of another color out there. Some of you are right now thinking, aren’t some swans black? Indeed they are. And how many black swans did we need to observe to prove our hypothesis wrong?

Just one.

There are two take-home messages in this story. The first is that science does not progress by proving itself right, as many suppose. Observing one more white swan does not really add substantially to our body of knowledge. We do, however, learn something useful by proving ourselves wrong. A single black swan observation disproved our hypothesis.

The next message is that even if we didn’t see that black swan, we need to be open to there being one somewhere in the world. As evidence is accumulated for a given explanation, our confidence in that conclusion grows, but it will never reach one hundred percent. In fact, scientists generally cannot claim anything is one hundred percent certain. The public has been misled by the claim in the past, as when a scientist was asked if he was one hundred percent certain that climate change was caused by humans. This is the reason why, even when a strong body of evidence, absolute certainty is not possible.

Statistical tests are often invoked to assess this level of certainty, thus relieving the scientist from making a judgement, which may open the door to bias.

This is an important aspect of scientific investigation. For instance, a particular hypothesis might be supported by many confirming experiments or observations. This does not, however, serve to “prove” the hypothesis – rather, it only supports its conditional acceptance. As soon as a clearly defined hypothesis is falsified by an appropriately designed and well-conducted experiment, it is disproved for all time. This is why experiments designed to disprove hypotheses are a key aspect of the scientific method.

Principles of Scientific Inquiry

In the world of science, research and conclusions are held to very high standards. Scientific research must undergo peer review before it can be published. During this process, experts in the specific field subject the research findings to an exhaustive review to ensure that the research is properly conducted, the results are accurate, and that the conclusions are justified. As a result, published science is considered to be a very reliable source of information.

Another characteristic of science is that it should be unbiased . Researchers should not let vested interests guide their research endeavors or conclusions. This is an area in which complications often arise. Researchers, even when they are employed at public research institutions, often must solicit funding to pursue their research projects from government agencies or private donors (often corporations). One the one hand, in order to get funded, they must cater their research to the interests of the funding agencies, and further, they may fear that if their results are not in the interest of their donors, they may lose funding. One might imagine that a chemical corporation that makes large donations to a university would not appreciate a researcher from that institution publishing a study showing that the chemicals manufactured by that company are linked to cancer.

One way that researchers avoid bias is through transparency. Scientific studies that are published generally consist of four separate sections: In Introduction, Methods, Results and Conclusion or Discussion. The Methods section includes an exhaustive account of how the study as conducted so that other researchers can replicate the study as a means of verifying or contradicting the results. The Results section includes the findings of the study, or in graphic or tabular form. This allows readers to ascertain what the basis is for the conclusions that were drawn in the study.

When science undergoes rigorous peer review, the publications are considered to be a primary resource and are considered to carry a significant amount of authority. Most of the public, however, has very little exposure to these resources. You will not find them in bookstores or at community libraries for the most part. To access them directly, you generally need to have access to a college or university library, where they are often available as digital resources. Alternatively, you may subscribe to them directly, but they are generally not free.

How is scientific information disseminated to the public then? Usually by way of secondary literature . These are magazines, newspapers or websites that report on new advances in science. While they are often quite accurate, they are not as authoritative because they are not written by the expert in the field and do not undergo peer review. Within this category, there are also a number of publications that are demonstrably inaccurate and misleading. This places the burden of developing a very discerning eye for what constitutes an accurate portrayal of scientific information on the general public. Some questions to ask are, is this a publication or website that I am familiar with and that I know to be reputable? Does it have a thorough list of references that I can refer to? Is the author a reputable figure in the field? Keep in mind that the internet has no constraints on the factual nature of what can be posted, and the resources that appear first when you conduct a search are not necessarily the most accurate ones.

Government agencies and research bodies may also be reliable sources of information, but they are prone to the same pitfalls and biases as other realms of science. In essence, the political climate at a given time may impact the presentation of information. While government reports are often posted online for public consumption, they have not necessarily undergone peer review.

It is always a good idea to approach information, particularly when it relates to an issue that is either contentious or political in nature with a healthy bit of skepticism. One advantage of achieving a working level of scientific literacy is that it qualifies you to be a discerning judge of the validity of the information you read.

Conclusions

The procedures and methods of science are important in the identifying, understanding, and resolving environmental problems. At the same time, however, social and economic issues are also vital considerations. Although science has made tremendous progress in helping us to understand the natural world, the extreme complexity of biology and ecosystems makes it difficult for environmental scientists to make reliable predictions about the consequences of many human economic activities and other influences. This context underscores the need for continued study of the scientific and socio-economic dimensions of environmental problems, even while practical decisions must be made to deal with obvious issues as they arise.

Questions for Review

Outline the reasons why science is a rational way of understanding the natural world.
Why are null hypotheses an efficient way to conduct scientific research? Identify a hypothesis that is suitable for examining a specific problem in environmental science and suggest a corresponding null hypothesis that could be examined through research.

Questions for Discussion

What are the key differences between science and a less objective belief system, such as religion?
What factors result in scientific controversies about environmental issues? Contrast these with environmental controversies that exist because of differing values and world views.
Many natural phenomena are highly variable, particularly ones that are biological or ecological. What are the implications of this variability for understanding and predicting the causes and consequences of environmental changes? How do environmental scientists cope with this challenge of a variable natural world?

Exploring Issues

Devise an environmental question of interest to yourself. Suggest useful hypotheses to investigate, identify the null hypotheses, and outline experiments that you might conduct to provide answers to this question.
During a research project investigating mercury, an environmental scientist performed a series of chemical analyses of fish caught in Lake Canuck. The sampling program involved seven species of fish obtained from various habitats within the lake. A total of 360 fish of various sizes and sexes were analyzed. It was discovered that 30% of the fish had residue levels greater than 0.5 ppm of mercury, the upper level of contamination recommended by Health Canada for fish eaten by humans. The scientist reported these results to a governmental regulator, who was alarmed by the high mercury residues because of Lake Canuck’s popularity as a place where people fish for food. The regulator asked the scientist to recommend whether it was safe to eat any fish from the lake or whether to avoid only certain sizes, sexes, species, or habitats. What sorts of data analyses should the scientist perform to develop useful recommendations? What other scientific and non-scientific aspects should be considered?

References Cited and Further Reading

American Association for the Advancement of Science (AAAS). 1990. Science for All Americans. AAAS, Washington, DC.

Barnes, B. 1985. About Science. Blackwell Ltd ,London, UK.

Giere, R.N. 2005. Understanding Scientific Reasoning. 5th ed. Wadsworth Publishing, New York, NY.

Kuhn, T.S. 1996. The Structure of Scientific Revolutions. 3rd ed. University of Chicago Press, Chicago, IL.

McCain, G. and E.M. Siegal. 1982. The Game of Science. Holbrook Press Inc., Boston, MA.

Moore, J.A. 1999. Science as a Way of Knowing. Harvard University Press, Boston, MA.

Popper, K. 1979. Objective Knowledge: An Evolutionary Approach. Clarendon Press, Oxford, UK.

Raven, P.H., G.B. Johnson, K.A. Mason, and J. Losos. 2013. Biology. 10th ed. McGraw-Hill, Columbus, OH.

Silver, B.L. 2000. The Ascent of Science. Oxford University Press, Oxford, UK.

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2: Science as a Way of Understanding the Natural World

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Page ID 42025

Bill Freedman
Dalhousie University via BCCampus

Learning Objectives

After completing this chapter, you will be able to

Describe the nature of science and its usefulness in explaining the natural world.
Distinguish among facts, hypotheses, and theories.
Outline the methodology of science, including the importance of tests designed to disprove hypotheses.
Discuss the importance of uncertainty in many scientific predictions, and the relevance of this to environmental controversies.

The Nature of Science

Science can be defined as the systematic examination of the structure and functioning of the natural world, including both its physical and biological attributes. Science is also a rapidly expanding body of knowledge, whose ultimate goal is to discover the simplest general principles that can explain the enormous complexity of nature. These principles can be used to gain insights about the of the natural world and to make predictions about future change.

Science is a relatively recent way of learning about natural phenomena, having largely replaced the influences of less objective methods and world views. The major alternatives to science are belief systems that are influential in all cultures, including those based on religion, morality, and aesthetics. These belief systems are primarily directed toward different ends than science, such as finding meaning that transcends mere existence, learning how people ought to behave, and understanding the value of artistic expression.

Modern science evolved from a way of learning called natural philosophy, which was developed by classical Greeks and was concerned with the rational investigation of existence, knowledge, and phenomena. Compared with modern science, however, studies in natural philosophy used unsophisticated technologies and methods and were not particularly quantitative, sometimes involving only the application of logic.

Modern science began with the systematic investigations of famous 16th- and 17th-century scientists, such as:

Nicolaus Copernicus (1473-1543), a Polish astronomer who conceived the modern theory of the solar system
William Gilbert (1544-1603), an Englishman who worked on magnetism
Galileo Galilei (1564-1642), an Italian who conducted research on the physics of objects in motion, as well as astronomy
William Harvey (1578-1657): an Englishman who described the circulation of the blood
Isaac Newton (1642-1727): an Englishman who made important contributions to understanding gravity and the nature of light, formulated laws of motion, and developed the mathematics of calculus

Inductive and Deductive Logic

The English philosopher Francis Bacon (1561-1626) was also highly influential in the development of modern science. Bacon was not an actual practitioner of science but was a strong proponent of its emerging methodologies. He promoted the application of inductive logic, in which conclusions are developed from the accumulating evidence of experience and the results of experiments. Inductive logic can lead to unifying explanations based on large bodies of data and observations of phenomena. Consider the following illustration of inductive logic, applied to an environmental topic:

Observation 1: Marine mammals off the Atlantic coast of Canada have large residues of DDT and other chlorinated hydrocarbons in their fat and other body tissues.
Observation 2: So do marine mammals off British Columbia.
Observation 3: As do those in the Arctic Ocean, although in lower concentrations.

Inductive conclusion: There is a widespread contamination of marine mammals with chlorinated hydrocarbons. Further research may demonstrate that the contamination is a global phenomenon. This suggests a potentially important environmental problem.

In contrast, deductive logic involves making one or more initial assumptions and then drawing logical conclusions from those premises. Consequently, the truth of a deductive conclusion depends on the veracity of the original assumptions. If those suppositions are based on false information or on incorrect supernatural belief, then any deduced conclusions are likely to be wrong. Consider the following illustration of deductive logic:

Assumption 1: TCDD, an extremely toxic chemical in the dioxin family, is poisonous when present in even the smallest concentrations in food and water—even a single molecule can cause toxicity.
Assumption 2: Exposure to anything that is poisonous in even the smallest concentrations is unsafe.
Assumption 3: No exposure that is unsafe should be allowed.

Deductive conclusion 1: No exposure to TCDD is safe. Deductive conclusion 2: No emissions of TCDD should be allowed.

The two conclusions are consistent with the original assumptions. However, there is disagreement among highly qualified scientists about those assumptions. Many toxicologists believe that exposures to TCDD (and any other potentially toxic chemicals) must exceed a threshold of biological tolerance before poisoning will result (see Chapter 15). In contrast, other scientists believe that even the smallest exposure to TCDD carries some degree of toxic risk. Thus, the strength of deductive logic depends on the acceptance and truth of the original assumptions from which its conclusions flow.

In general, inductive logic plays a much stronger role in modern science than does deductive logic. In both cases, however, the usefulness of any conclusions depends greatly on the accuracy of any observations and other data on which they were based. Poor data may lead to an inaccurate conclusion through the application of inductive logic, as will inappropriate assumptions in deductive logic.

Goals of Science

The broad goals of science are to understand natural phenomena and to explain how they may be changing over time. To achieve those goals, scientists undertake investigations that are based on information, inferences, and conclusions developed through a systematic application of logic, usually of the inductive sort. As such, scientists carefully observe natural phenomena and conduct experiments.

A higher goal of scientific research is to formulate laws that describe the workings of the universe in general terms. (For example, see Chapter 4 for a description of the laws of thermodynamics, which deal with the transformations of energy among its various states.) Universal laws, along with theories and hypotheses (see below), are used to understand and explain natural phenomena. However, many natural phenomena are extremely complex and may never be fully understood in terms of physical laws. This is particularly true of the ways that organisms and ecosystems are organized and function.

Facts, Hypotheses, and Experiments

the theory of gravitation, first proposed by Isaac Newton (1642-1727)
the theory of evolution by natural selection, published simultaneously in 1858 by two English naturalists, Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913)
the theory of relativity, identified by the German–Swiss physicist, Albert Einstein (1879-1955)

The scientific method begins with the identification of a question involving the structure or function of the natural world, which is usually developed using inductive logic (Figure 2.1). The question is interpreted in terms of existing theory, and specific hypotheses are formulated to explain the character and causes of the natural phenomenon. The research might involve observations made in nature, or carefully controlled experiments, and the results usually give scientists reasons to reject hypotheses rather than to accept them. Most hypotheses are rejected because their predictions are not borne out during the course of research. Any viable hypotheses are further examined through additional research, again largely involving experiments designed to disprove their predictions. Once a large body of evidence accumulates in support of a hypothesis, it can be used to corroborate the original theory.

The scientific method is only to investigate questions that can be critically examined through observation and experiment. Consequently, science cannot resolve value-laden questions, such as the meaning of life, good versus evil, or the existence and qualities of God or any other supernatural being or force.

By far the most useful working hypotheses in scientific research are designed to disprove rather than support. A null hypothesis is a specific testable investigation that denies something implied by the main hypothesis being studied. Unless null hypotheses are eliminated on the basis of contrary evidence, we cannot be confident of the main hypothesis.

Revolutionary advances in understanding may occur when an important hypothesis or theory are rejected through discoveries of science. For instance, once it was discovered that the Earth is not flat, it became possible to confidently sail beyond the visible horizon without fear of falling off the edge of the world. Another example involved the discovery by Copernicus that the planets of our solar system revolve around the Sun, and the related concept that the Sun is an ordinary star among many – these revolutionary ideas replaced the previously dominant one that the planets, Sun, and stars all revolved around the Earth.

Thomas Kuhn (1922-1995) was a philosopher of science who emphasized the important role of “scientific revolutions” in achieving great advances in our understanding of the natural world. In essence, Kuhn (1996) said that a scientific revolution occurs when a well-established theory is rigorously tested and then collapses under the accumulating weight of new facts and observations that cannot be explained. This renders the original theory obsolete, to be replaced by a new, more informed paradigm (i.e., a set of assumptions, concepts, practices, and values that constitutes a way of viewing reality and is shared by an intellectual community).

A variable is a factor that is believed to influence a natural phenomenon. For example, a scientist might hypothesize that the productivity of a wheat crop is potentially limited by such variables as the availability of water, or of nutrients such as nitrogen and phosphorus. Some of the most powerful scientific experiments involve the manipulation of key (or controlling) variables and the comparison of results of those treatments with a control that was not manipulated. In the example just described, the specific variable that controls wheat productivity could be identified by conducting an experiment in which test populations are provided with varying amounts of water, nitrogen, and phosphorus, alone and in combination, and then comparing the results with a non-manipulated control.

In some respects, however, the explanation of the scientific method offered above is a bit uncritical. It perhaps suggests a too-orderly progression in terms of logical, objective experimentation and comparison of alternative hypotheses. These are, in fact, important components of the scientific method. Nevertheless, it is important to understand that the insights and personal biases of scientists are also significant in the conduct and progress of science. In most cases, scientists design research that they think will “work” to yield useful results and contribute to the orderly advancement of knowledge in their field. Karl Popper (1902-1994), a European philosopher, noted that scientists tend to use their “imaginative preconception” of the workings of the natural world to design experiments based on their informed insights. This means that effective scientists must be more than knowledgeable and technically skilled – they should also be capable of a degree of insightful creativity when forming their ideas, hypotheses, and research.

Uncertainty

Much scientific investigation involves the collection of observations by measuring phenomena in the natural world. Another important aspect of science involves making predictions about the future values of variables. Such projections require a degree of understanding of the relationships among variables and their influencing factors, and of recent patterns of change. However, many kinds of scientific information and predictions are subject to inaccuracy. This occurs because measured data are often approximations of the true values of phenomena, and predictions are rarely fulfilled exactly. The accuracy of observations and predictions is influenced by various factors, especially those described in the following sections.

Predictability

A few phenomena are considered to have a universal character and are consistent wherever and whenever they are accurately measured. One of the best examples of such a universal constant is the speed of light, which always has a value of 2.998 × 10 8 meters per second, regardless of where it is measured or of the speed of the body from which the light is emitted. Similarly, certain relationships describing transformations of energy and matter, known as the laws of thermodynamics (Chapter 4), always give reliable predictions.

However, most natural phenomena are not so consistent—depending on circumstances, there are exceptions to general predictions about them. This circumstance is particularly true of biology and ecology, related fields of science in which almost all general predictions have exceptions. In fact, laws or unifying principles of biology or ecology have not yet been discovered, in contrast to the several esteemed laws and 11 universal constants of physics. For this reason, biologists and ecologists have great difficulties making accurate predictions about the responses of organisms and ecosystems to environmental change. This is why biologists and ecologists are sometimes said to have “physics envy.”

In large part, the inaccuracies of biology and ecology occur because key functions are controlled by complexes of poorly understood, and sometimes unidentified, environmental influences. Consequently, predictions about future values of biological and ecological variables or the causes of changes are seldom accurate. For example, even though ecologists in eastern Canada have been monitoring the population size of spruce budworm (an important pest of conifer forests) for some years, they cannot accurately predict its future abundance in particular stands of forest or in larger regions. This is because the abundance of this moth is influenced by a complex of environmental factors, including tree-species composition, age of the forest, abundance of its predators and parasites, quantities of its preferred foods, weather at critical times of year, and insecticide use to reduce its populations (see Chapter 21). Biologists and ecologists do not fully understand this complexity, and perhaps they never will.

Variability

Many natural phenomena are highly variable in space and time. This is true of physical and chemical variables as well as of biological and ecological ones. Within a forest, for example, the amount of sunlight reaching the ground varies greatly with time, depending on the hour of the day and the season of the year. It also varies spatially, depending on the density of foliage over any place where sunlight is being measured. Similarly, the density of a particular species of fish within a river typically varies in response to changes in habitat conditions and other influences. Most fish populations also vary over time, especially migratory species such as salmon. In environmental science, replicated (or independently repeated) measurements and statistical analyses are used to measure and account for these kinds of temporal and spatial variations.

Accuracy and Precision

Accuracy refers to the degree to which a measurement or observation reflects the actual, or true, value of the subject. For example, the insecticide DDT and the metal mercury are potentially toxic chemicals that occur in trace concentrations in all organisms, but their small residues are difficult to analyze chemically. Some of the analytical methods used to determine the concentrations of DDT and mercury are more accurate than others and therefore provide relatively useful and reliable data compared with less accurate methods. In fact, analytical data are usually approximations of the real values – rigorous accuracy is rarely attainable.

Precision is related to the degree of repeatability of a measurement or observation. For example, suppose that the actual number of caribou in a migrating herd is 10,246 animals. A wildlife ecologist might estimate that there were about 10,000 animals in that herd, which for practical purposes is a reasonably accurate reckoning of the actual number of caribou. If other ecologists also independently estimate the size of the herd at about 10,000 caribou, there is a good degree of precision among the values. If, however, some systematic bias existed in the methodology used to count the herd, giving consistent estimates of 15,000 animals (remember, the actual population is 10 246 caribou), these estimates would be considered precise, but not particularly accurate.

Precision is also related to the number of digits with which data are reported. If you were using a flexible tape to measure the lengths of 10 large, wriggly snakes, you would probably measure the reptiles only to the nearest centimetre. The strength and squirminess of the animals make more precise measurements impossible. The reported average length of the 10 snakes should reflect the original measurements and might be given as 204 cm and not a value such as 203.8759 cm. The latter number might be displayed as a digital average by a calculator or computer, but it is unrealistically precise.

Significant figures are related to accuracy and precision and can be defined as the number of digits used to report data from analyses or calculations (see also Appendix A). Significant figures are most easily understood by examples. The number 179 has three significant figures, as does the number 0.0849 and also 0.000794 (the zeros preceding the significant integers do not count). However, the number 195,000,000 has nine significant figures (the zeros following are meaningful), although the number 195 × 10 6 has only three significant figures.

It is rarely useful to report environmental or ecological data to more than 2-4 significant figures. This is because any more would generally exceed the accuracy and precision of the methodology used in the estimation and would therefore be unrealistic. For example, the approximate population of Canada in 2015 was 35.1 million people (or 35.1 × 10 6 ; both of these notations have three significant figures). However, the population should not be reported as 33,100,000, which implies an unrealistic accuracy and precision of eight significant figures.

A Need for Scepticism

Environmental science is filled with many examples of uncertainty—in present values and future changes of environmental variables, as well as in predictions of biological and ecological responses to those changes. To some degree the difficulties associated with scientific uncertainty can be mitigated by developing improved methods and technologies for analysis and by modelling and examining changes occurring in different parts of the world. The latter approach enhances our understanding by providing convergent evidence about the occurrence and causes of natural phenomena.

However, scientific information and understanding will always be subject to some degree of uncertainty. Therefore, predictions will always be inaccurate to some extent, and this uncertainty must be considered when trying to understand and deal with the causes and consequences of environmental changes. As such, all information and predictions in environmental science must be critically interpreted with uncertainty in mind (In Detail 2.1). This should be done whenever one is learning about an environmental issue, whether it involves listening to a speaker in a classroom, at a conference, or on video, or when reading an article in a newspaper, textbook, website, or scientific journal. Because of the uncertainty of many predictions in science, and particularly in the environmental realm, a certain amount of scepticism and critical analysis is always useful.

Environmental issues are acutely important to the welfare of people and other species. Science and its methods allow for a critical and objective identification of key issues, the investigation of their causes, and a degree of understanding of the consequences of environmental change. Scientific information influences decision making about environmental issues, including whether to pursue expensive strategies to avoid further, but often uncertain, damage.

Scientific information is, however, only one consideration for decision makers, who are also concerned with the economic, cultural, and political contexts of environmental problems (see Environmental Issues 1.1 and Chapter 27). In fact, when deciding how to deal with the causes and consequences of environmental changes, decision makers may give greater weight to non-scientific (social and economic) considerations than to scientific ones, especially when there is uncertainty about the latter. The most important decisions about environmental issues are made by politicians and senior bureaucrats in government, or by private managers, rather than by environmental scientists. Decision makers typically worry about the short-term implications of their decisions on their chances for re-election or continued employment, and on the economic activity of a company or society at large, as much as they do about the consequences of environmental damage (see also Chapter 27).

In Detail 2.1. Critical Evaluation of an Overload of Information More so than any previous society, we live today in a world of easy and abundant information. It has become remarkably easy for people to communicate with others over vast distances, turning the world into a “global village” (a phrase coined by Marshall McLuhan (1911-1980), a Canadian philosopher, to describe the phenomenon of universal networking). This global connectedness has been facilitated by technologies for transferring ideas and knowledge—particularly electronic communication devices, such as radio, television, computers, and their networks. Today, these technologies compress space and time to achieve a virtually instantaneous communication. In fact, so much information is now available that the situation is often referred to as an “information overload” that must be analyzed critically. Critical analysis is the process of sorting information and making scientific enquiries about data. Involved in all aspects of the scientific process, critical analysis scrutinizes information and research by posing sensible questions such as the following:

Is the information derived from a scientific framework consisting of a hypothesis that has been developed and tested, within the context of an existing body of knowledge and theory in the field?
Were the methodologies used likely to provide data that are objective, accurate, and precise? Were the data analyzed by statistical methods that are appropriate to the data structure and to the questions being asked?
Were the results of the research compared with other pertinent work that has been previously published? Were key similarities and differences discussed and a conclusion deduced about what the new work reveals about the issue being investigated?
Is the information based on research published in a refereed journal—one that requires highly qualified reviewers in the subject area to scrutinize the work, followed by an editorial decision about whether it warrants publication?
If the analysis of an issue was based on incomplete or possibly inaccurate information, was a precautionary approach used in order to accommodate the uncertainty inherent in the recommendations? All users of published research have an obligation to critically evaluate what they are reading in these ways in order to decide whether the theory is appropriate, the methodologies reliable, and the conclusions sufficiently robust. Because so many environmental issues are controversial, with data and information presented on both sides of the debate, people need to be able to formulate objectively critical judgments. For this reason, people need a high degree of environmental literacy—an informed understanding of the causes and consequences of environmental damages. Being able to critically analyze information is a key personal benefit of studying environmental science.

Conclusions

Questions for Review

Outline the reasons why science is a rational way of understanding the natural world.
What are the differences between inductive and deductive logic? Why is inductive logic more often used by scientists when formulating hypotheses and generalizations about the natural world?
Why are null hypotheses an efficient way to conduct scientific research? Identify a hypothesis that is suitable for examining a specific problem in environmental science and suggest a corresponding null hypothesis that could be examined through research.
What are the causes of variation in natural phenomena? Choose an example, such as differences in the body weights of a defined group of people, and suggest reasons for the variation.

Questions for Discussion

What are the key differences between science and a less objective belief system, such as religion?
What factors result in scientific controversies about environmental issues? Contrast these with environmental controversies that exist because of differing values and world views.
Explain why there are no scientific “laws” to explain the structure and function of ecosystems.
Many natural phenomena are highly variable, particularly ones that are biological or ecological. What are the implications of this variability for understanding and predicting the causes and consequences of environmental changes? How do environmental scientists cope with this challenge of a variable natural world?

Exploring Issues

Devise an environmental question of interest to yourself. Suggest useful hypotheses to investigate, identify the null hypotheses, and outline experiments that you might conduct to provide answers to this question.
During a research project investigating mercury, an environmental scientist performed a series of chemical analyses of fish caught in Lake Canuck. The sampling program involved seven species of fish obtained from various habitats within the lake. A total of 360 fish of various sizes and sexes were analyzed. It was discovered that 30% of the fish had residue levels greater than 0.5 ppm of mercury, the upper level of contamination recommended by Health Canada for fish eaten by humans. The scientist reported these results to a governmental regulator, who was alarmed by the high mercury residues because of Lake Canuck’s popularity as a place where people fish for food. The regulator asked the scientist to recommend whether it was safe to eat any fish from the lake or whether to avoid only certain sizes, sexes, species, or habitats. What sorts of data analyses should the scientist perform to develop useful recommendations? What other scientific and non-scientific aspects should be considered?

References Cited and Further Reading

American Association for the Advancement of Science (AAAS). 1990. Science for All Americans. AAAS, Washington, DC.
Barnes, B. 1985. About Science. Blackwell Ltd ,London, UK.
Giere, R.N. 2005. Understanding Scientific Reasoning. 5th ed. Wadsworth Publishing, New York, NY.
Kuhn, T.S. 1996. The Structure of Scientific Revolutions. 3rd ed. University of Chicago Press, Chicago, IL.
McCain, G. and E.M. Siegal. 1982. The Game of Science. Holbrook Press Inc., Boston, MA.
Moore, J.A. 1999. Science as a Way of Knowing. Harvard University Press, Boston, MA.
Popper, K. 1979. Objective Knowledge: An Evolutionary Approach. Clarendon Press, Oxford, UK.
Raven, P.H., G.B. Johnson, K.A. Mason, and J. Losos. 2013. Biology. 10th ed. McGraw-Hill, Columbus, OH.
Silver, B.L. 2000. The Ascent of Science. Oxford University Press, Oxford, UK.

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A Guide to Using the Scientific Method in Everyday Life

The scientific method —the process used by scientists to understand the natural world—has the merit of investigating natural phenomena in a rigorous manner. Working from hypotheses, scientists draw conclusions based on empirical data. These data are validated on large-scale numbers and take into consideration the intrinsic variability of the real world. For people unfamiliar with its intrinsic jargon and formalities, science may seem esoteric. And this is a huge problem: science invites criticism because it is not easily understood. So why is it important, then, that every person understand how science is done?

Because the scientific method is, first of all, a matter of logical reasoning and only afterwards, a procedure to be applied in a laboratory.

Individuals without training in logical reasoning are more easily victims of distorted perspectives about themselves and the world. An example is represented by the so-called “ cognitive biases ”—systematic mistakes that individuals make when they try to think rationally, and which lead to erroneous or inaccurate conclusions. People can easily overestimate the relevance of their own behaviors and choices. They can lack the ability to self-estimate the quality of their performances and thoughts . Unconsciously, they could even end up selecting only the arguments that support their hypothesis or beliefs . This is why the scientific framework should be conceived not only as a mechanism for understanding the natural world, but also as a framework for engaging in logical reasoning and discussion.

A brief history of the scientific method

The scientific method has its roots in the sixteenth and seventeenth centuries. Philosophers Francis Bacon and René Descartes are often credited with formalizing the scientific method because they contrasted the idea that research should be guided by metaphysical pre-conceived concepts of the nature of reality—a position that, at the time, was highly supported by their colleagues . In essence, Bacon thought that inductive reasoning based on empirical observation was critical to the formulation of hypotheses and the generation of new understanding : general or universal principles describing how nature works are derived only from observations of recurring phenomena and data recorded from them. The inductive method was used, for example, by the scientist Rudolf Virchow to formulate the third principle of the notorious cell theory , according to which every cell derives from a pre-existing one. The rationale behind this conclusion is that because all observations of cell behavior show that cells are only derived from other cells, this assertion must be always true.

Inductive reasoning, however, is not immune to mistakes and limitations. Referring back to cell theory, there may be rare occasions in which a cell does not arise from a pre-existing one, even though we haven’t observed it yet—our observations on cell behavior, although numerous, can still benefit from additional observations to either refute or support the conclusion that all cells arise from pre-existing ones. And this is where limited observations can lead to erroneous conclusions reasoned inductively. In another example, if one never has seen a swan that is not white, they might conclude that all swans are white, even when we know that black swans do exist, however rare they may be.

The universally accepted scientific method, as it is used in science laboratories today, is grounded in hypothetico-deductive reasoning . Research progresses via iterative empirical testing of formulated, testable hypotheses (formulated through inductive reasoning). A testable hypothesis is one that can be rejected (falsified) by empirical observations, a concept known as the principle of falsification . Initially, ideas and conjectures are formulated. Experiments are then performed to test them. If the body of evidence fails to reject the hypothesis, the hypothesis stands. It stands however until and unless another (even singular) empirical observation falsifies it. However, just as with inductive reasoning, hypothetico-deductive reasoning is not immune to pitfalls—assumptions built into hypotheses can be shown to be false, thereby nullifying previously unrejected hypotheses. The bottom line is that science does not work to prove anything about the natural world. Instead, it builds hypotheses that explain the natural world and then attempts to find the hole in the reasoning (i.e., it works to disprove things about the natural world).

How do scientists test hypotheses?

Controlled experiments

The word “experiment” can be misleading because it implies a lack of control over the process. Therefore, it is important to understand that science uses controlled experiments in order to test hypotheses and contribute new knowledge. So what exactly is a controlled experiment, then?

Let us take a practical example. Our starting hypothesis is the following: we have a novel drug that we think inhibits the division of cells, meaning that it prevents one cell from dividing into two cells (recall the description of cell theory above). To test this hypothesis, we could treat some cells with the drug on a plate that contains nutrients and fuel required for their survival and division (a standard cell biology assay). If the drug works as expected, the cells should stop dividing. This type of drug might be useful, for example, in treating cancers because slowing or stopping the division of cells would result in the slowing or stopping of tumor growth.

Although this experiment is relatively easy to do, the mere process of doing science means that several experimental variables (like temperature of the cells or drug, dosage, and so on) could play a major role in the experiment. This could result in a failed experiment when the drug actually does work, or it could give the appearance that the drug is working when it is not. Given that these variables cannot be eliminated, scientists always run control experiments in parallel to the real ones, so that the effects of these other variables can be determined. Control experiments are designed so that all variables, with the exception of the one under investigation, are kept constant. In simple terms, the conditions must be identical between the control and the actual experiment.

Coming back to our example, when a drug is administered it is not pure. Often, it is dissolved in a solvent like water or oil. Therefore, the perfect control to the actual experiment would be to administer pure solvent (without the added drug) at the same time and with the same tools, where all other experimental variables (like temperature, as mentioned above) are the same between the two (Figure 1). Any difference in effect on cell division in the actual experiment here can be attributed to an effect of the drug because the effects of the solvent were controlled.

In order to provide evidence of the quality of a single, specific experiment, it needs to be performed multiple times in the same experimental conditions. We call these multiple experiments “replicates” of the experiment (Figure 2). The more replicates of the same experiment, the more confident the scientist can be about the conclusions of that experiment under the given conditions. However, multiple replicates under the same experimental conditions are of no help when scientists aim at acquiring more empirical evidence to support their hypothesis. Instead, they need independent experiments (Figure 3), in their own lab and in other labs across the world, to validate their results.

Often times, especially when a given experiment has been repeated and its outcome is not fully clear, it is better to find alternative experimental assays to test the hypothesis.

Applying the scientific approach to everyday life

So, what can we take from the scientific approach to apply to our everyday lives?

A few weeks ago, I had an agitated conversation with a bunch of friends concerning the following question: What is the definition of intelligence?

Defining “intelligence” is not easy. At the beginning of the conversation, everybody had a different, “personal” conception of intelligence in mind, which – tacitly – implied that the conversation could have taken several different directions. We realized rather soon that someone thought that an intelligent person is whoever is able to adapt faster to new situations; someone else thought that an intelligent person is whoever is able to deal with other people and empathize with them. Personally, I thought that an intelligent person is whoever displays high cognitive skills, especially in abstract reasoning.

The scientific method has the merit of providing a reference system, with precise protocols and rules to follow. Remember: experiments must be reproducible, which means that an independent scientists in a different laboratory, when provided with the same equipment and protocols, should get comparable results. Fruitful conversations as well need precise language, a kind of reference vocabulary everybody should agree upon, in order to discuss about the same “content”. This is something we often forget, something that was somehow missing at the opening of the aforementioned conversation: even among friends, we should always agree on premises, and define them in a rigorous manner, so that they are the same for everybody. When speaking about “intelligence”, we must all make sure we understand meaning and context of the vocabulary adopted in the debate (Figure 4, point 1). This is the first step of “controlling” a conversation.

There is another downside that a discussion well-grounded in a scientific framework would avoid. The mistake is not structuring the debate so that all its elements, except for the one under investigation, are kept constant (Figure 4, point 2). This is particularly true when people aim at making comparisons between groups to support their claim. For example, they may try to define what intelligence is by comparing the achievements in life of different individuals: “Stephen Hawking is a brilliant example of intelligence because of his great contribution to the physics of black holes”. This statement does not help to define what intelligence is, simply because it compares Stephen Hawking, a famous and exceptional physicist, to any other person, who statistically speaking, knows nothing about physics. Hawking first went to the University of Oxford, then he moved to the University of Cambridge. He was in contact with the most influential physicists on Earth. Other people were not. All of this, of course, does not disprove Hawking’s intelligence; but from a logical and methodological point of view, given the multitude of variables included in this comparison, it cannot prove it. Thus, the sentence “Stephen Hawking is a brilliant example of intelligence because of his great contribution to the physics of black holes” is not a valid argument to describe what intelligence is. If we really intend to approximate a definition of intelligence, Steven Hawking should be compared to other physicists, even better if they were Hawking’s classmates at the time of college, and colleagues afterwards during years of academic research.

In simple terms, as scientists do in the lab, while debating we should try to compare groups of elements that display identical, or highly similar, features. As previously mentioned, all variables – except for the one under investigation – must be kept constant.

This insightful piece presents a detailed analysis of how and why science can help to develop critical thinking.

In a nutshell

Here is how to approach a daily conversation in a rigorous, scientific manner:

First discuss about the reference vocabulary, then discuss about the content of the discussion. Think about a researcher who is writing down an experimental protocol that will be used by thousands of other scientists in varying continents. If the protocol is rigorously written, all scientists using it should get comparable experimental outcomes. In science this means reproducible knowledge, in daily life this means fruitful conversations in which individuals are on the same page.
Adopt “controlled” arguments to support your claims. When making comparisons between groups, visualize two blank scenarios. As you start to add details to both of them, you have two options. If your aim is to hide a specific detail, the better is to design the two scenarios in a completely different manner—it is to increase the variables. But if your intention is to help the observer to isolate a specific detail, the better is to design identical scenarios, with the exception of the intended detail—it is therefore to keep most of the variables constant. This is precisely how scientists ideate adequate experiments to isolate new pieces of knowledge, and how individuals should orchestrate their thoughts in order to test them and facilitate their comprehension to others.

Not only the scientific method should offer individuals an elitist way to investigate reality, but also an accessible tool to properly reason and discuss about it.

Edited by Jason Organ, PhD, Indiana University School of Medicine.

Simone is a molecular biologist on the verge of obtaining a doctoral title at the University of Ulm, Germany. He is Vice-Director at Culturico (https://culturico.com/), where his writings span from Literature to Sociology, from Philosophy to Science. His writings recently appeared in Psychology Today, openDemocracy, Splice Today, Merion West, Uncommon Ground and The Society Pages. Follow Simone on Twitter: @simredaelli

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This has to be the best article I have ever read on Scientific Thinking. I am presently writing a treatise on how Scientific thinking can be adopted to entreat all situations.And how, a 4 year old child can be taught to adopt Scientific thinking, so that, the child can look at situations that bothers her and she could try to think about that situation by formulating the right questions. She may not have the tools to find right answers? But, forming questions by using right technique ? May just make her find a way to put her mind to rest even at that level. That is why, 4 year olds are often “eerily: (!)intelligent, I have iften been intimidated and plain embarrassed to see an intelligent and well spoken 4 year old deal with celibrity ! Of course, there are a lot of variables that have to be kept in mind in order to train children in such controlled thinking environment, as the screenplay of little Sheldon shows. Thanking the author with all my heart – #ershadspeak #wearescience #weareallscientists Ershad Khandker

Simone, thank you for this article. I have the idea that I want to apply what I learned in Biology to everyday life. You addressed this issue, and have given some basic steps in using the scientific method.

Biology library

Course: biology library > unit 1, the scientific method.

Controlled experiments
The scientific method and experimental design

Introduction

Make an observation.
Ask a question.
Form a hypothesis , or testable explanation.
Make a prediction based on the hypothesis.
Test the prediction.
Iterate: use the results to make new hypotheses or predictions.

Scientific method example: Failure to toast

1. make an observation..

Observation: the toaster won't toast.

2. Ask a question.

Question: Why won't my toaster toast?

3. Propose a hypothesis.

Hypothesis: Maybe the outlet is broken.

4. Make predictions.

Prediction: If I plug the toaster into a different outlet, then it will toast the bread.

5. Test the predictions.

Test of prediction: Plug the toaster into a different outlet and try again.
If the toaster does toast, then the hypothesis is supported—likely correct.
If the toaster doesn't toast, then the hypothesis is not supported—likely wrong.

Logical possibility

Practical possibility, building a body of evidence, 6. iterate..

Iteration time!
If the hypothesis was supported, we might do additional tests to confirm it, or revise it to be more specific. For instance, we might investigate why the outlet is broken.
If the hypothesis was not supported, we would come up with a new hypothesis. For instance, the next hypothesis might be that there's a broken wire in the toaster.

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Science News Explores

Scientists say: hypothesis.

This is an idea put forth to explain events in the natural world

In the process of making discoveries, scientists make hypotheses. These are ideas put forth to explain things in the natural world that scientists then investigate through experiments, observations and other methods.

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Hypothesis (noun, “Hi-PAH-theh-sis”)

This is an idea that may explain phenomena in the natural world. Making a hypothesis is one part of the process scientists use to make new discoveries. Before making a hypothesis, scientists may read about a topic to understand it better. They may talk with other scientists about it. Then they ask questions about things they don’t yet understand. The answers they propose are their hypotheses (“Hi-PAH-theh-SEAS”). Until confirmed, or disproven, such answers may be described as hypothetical ones.

For example, a team of biologists was studying how whales communicate. They knew that mother and baby humpback whales call quietly to each other when they migrate. So they formed a hypothesis that other kinds of whales also communicate quietly. To test this idea, researchers listened in on another species. They placed audio, or sound, recorders on mama southern right whales. The sound data they recorded showed that right whales whisper , too.

Other researchers use computer models to investigate their hypotheses. Models are very helpful when studying faraway things, like stars and planets. Some astronomers, for example, wonder if other planets have liquid water. Scientists have recently learned that a faraway planet called K2 18b has water vapor , the stuff clouds are made of. Could it also rain on that planet? To find out, researchers developed a computer model that simulated conditions on that planet.

In a sentence

Seeing that some hummingbirds have sharp or hooked bills led scientists to form the hypothesis that some birds use their bills as weapons .

Check out the full list of Scientists Say .

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1.2: The Process of Science

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Like geology, physics, and chemistry, biology is a science that gathers knowledge about the natural world. Specifically, biology is the study of life. The discoveries of biology are made by a community of researchers who work individually and together using agreed-on methods. In this sense, biology, like all sciences is a social enterprise like politics or the arts.

Photo A depicts round colonies of blue-green algae. Photo B depicts round fossil structures called stromatalites along a watery shoreline.

The methods of science include careful observation, record keeping, logical and mathematical reasoning, experimentation, and submitting conclusions to the scrutiny of others. Science also requires considerable imagination and creativity; a well-designed experiment is commonly described as elegant, or beautiful. Like politics, science has considerable practical implications and some science is dedicated to practical applications, such as the prevention of disease (Figure \(\PageIndex{2}\)). Other science proceeds largely motivated by curiosity. Whatever its goal, there is no doubt that science, including biology, has transformed human existence and will continue to do so.

Scanning electronic micrograph depicts E. coli bacteria aggregated together.

The Nature of Science

Biology is a science, but what exactly is science? What does the study of biology share with other scientific disciplines? Science (from the Latin scientia, meaning "knowledge") can be defined as knowledge about the natural world.

Science is a very specific way of learning, or knowing, about the world. The history of the past 500 years demonstrates that science is a very powerful way of knowing about the world; it is largely responsible for the technological revolutions that have taken place during this time. There are however, areas of knowledge and human experience that the methods of science cannot be applied to. These include such things as answering purely moral questions, aesthetic questions, or what can be generally categorized as spiritual questions. Science has cannot investigate these areas because they are outside the realm of material phenomena, the phenomena of matter and energy, and cannot be observed and measured.

The scientific method is a method of research with defined steps that include experiments and careful observation. The steps of the scientific method will be examined in detail later, but one of the most important aspects of this method is the testing of hypotheses. A hypothesis is a suggested explanation for an event, which can be tested. Hypotheses, or tentative explanations, are generally produced within the context of a scientific theory. A scientific theory is a generally accepted, thoroughly tested and confirmed explanation for a set of observations or phenomena. Scientific theory is the foundation of scientific knowledge. In addition, in many scientific disciplines (less so in biology) there are scientific laws, often expressed in mathematical formulas, which describe how elements of nature will behave under certain specific conditions. There is not an evolution of hypotheses through theories to laws as if they represented some increase in certainty about the world. Hypotheses are the day-to-day material that scientists work with and they are developed within the context of theories. Laws are concise descriptions of parts of the world that are amenable to formulaic or mathematical description.

Natural Sciences

What would you expect to see in a museum of natural sciences? Frogs? Plants? Dinosaur skeletons? Exhibits about how the brain functions? A planetarium? Gems and minerals? Or maybe all of the above? Science includes such diverse fields as astronomy, biology, computer sciences, geology, logic, physics, chemistry, and mathematics (Figure \(\PageIndex{3}\)). However, those fields of science related to the physical world and its phenomena and processes are considered natural sciences. Thus, a museum of natural sciences might contain any of the items listed above.

Some fields of science include astronomy, biology, computer science, geology, logic, physics, chemistry, and mathematics. (credit: "Image Editor/Flickr)"

There is no complete agreement when it comes to defining what the natural sciences include. For some experts, the natural sciences are astronomy, biology, chemistry, earth science, and physics. Other scholars choose to divide natural sciences into life sciences, which study living things and include biology, and physical sciences, which study nonliving matter and include astronomy, physics, and chemistry. Some disciplines such as biophysics and biochemistry build on two sciences and are interdisciplinary.

Scientific Inquiry

One thing is common to all forms of science: an ultimate goal “to know.” Curiosity and inquiry are the driving forces for the development of science. Scientists seek to understand the world and the way it operates. Two methods of logical thinking are used: inductive reasoning and deductive reasoning.

Inductive reasoning is a form of logical thinking that uses related observations to arrive at a general conclusion. This type of reasoning is common in descriptive science. A life scientist such as a biologist makes observations and records them. These data can be qualitative (descriptive) or quantitative (consisting of numbers), and the raw data can be supplemented with drawings, pictures, photos, or videos. From many observations, the scientist can infer conclusions (inductions) based on evidence. Inductive reasoning involves formulating generalizations inferred from careful observation and the analysis of a large amount of data. Brain studies often work this way. Many brains are observed while people are doing a task. The part of the brain that lights up, indicating activity, is then demonstrated to be the part controlling the response to that task.

Deductive reasoning or deduction is the type of logic used in hypothesis-based science. In deductive reasoning, the pattern of thinking moves in the opposite direction as compared to inductive reasoning. Deductive reasoning is a form of logical thinking that uses a general principle or law to forecast specific results. From those general principles, a scientist can extrapolate and predict the specific results that would be valid as long as the general principles are valid. For example, a prediction would be that if the climate is becoming warmer in a region, the distribution of plants and animals should change. Comparisons have been made between distributions in the past and the present, and the many changes that have been found are consistent with a warming climate. Finding the change in distribution is evidence that the climate change conclusion is a valid one.

Both types of logical thinking are related to the two main pathways of scientific study: descriptive science and hypothesis-based science. Descriptive (or discovery) science aims to observe, explore, and discover, while hypothesis-based science begins with a specific question or problem and a potential answer or solution that can be tested. The boundary between these two forms of study is often blurred, because most scientific endeavors combine both approaches. Observations lead to questions, questions lead to forming a hypothesis as a possible answer to those questions, and then the hypothesis is tested. Thus, descriptive science and hypothesis-based science are in continuous dialogue.

Hypothesis Testing

Biologists study the living world by posing questions about it and seeking science-based responses. This approach is common to other sciences as well and is often referred to as the scientific method. The scientific method was used even in ancient times, but it was first documented by England’s Sir Francis Bacon (1561–1626) (Figure \(\PageIndex{4}\)), who set up inductive methods for scientific inquiry. The scientific method is not exclusively used by biologists but can be applied to almost anything as a logical problem-solving method.

Painting depicts Sir Francis Bacon in a long cloak.

The scientific process typically starts with an observation (often a problem to be solved) that leads to a question. Let’s think about a simple problem that starts with an observation and apply the scientific method to solve the problem. One Monday morning, a student arrives at class and quickly discovers that the classroom is too warm. That is an observation that also describes a problem: the classroom is too warm. The student then asks a question: “Why is the classroom so warm?”

Recall that a hypothesis is a suggested explanation that can be tested. To solve a problem, several hypotheses may be proposed. For example, one hypothesis might be, “The classroom is warm because no one turned on the air conditioning.” But there could be other responses to the question, and therefore other hypotheses may be proposed. A second hypothesis might be, “The classroom is warm because there is a power failure, and so the air conditioning doesn’t work.”

Once a hypothesis has been selected, a prediction may be made. A prediction is similar to a hypothesis but it typically has the format “If . . . then . . . .” For example, the prediction for the first hypothesis might be, “ If the student turns on the air conditioning, then the classroom will no longer be too warm.”

A hypothesis must be testable to ensure that it is valid. For example, a hypothesis that depends on what a bear thinks is not testable, because it can never be known what a bear thinks. It should also be falsifiable, meaning that it can be disproven by experimental results. An example of an unfalsifiable hypothesis is “Botticelli’s Birth of Venus is beautiful.” There is no experiment that might show this statement to be false. To test a hypothesis, a researcher will conduct one or more experiments designed to eliminate one or more of the hypotheses. This is important. A hypothesis can be disproven, or eliminated, but it can never be proven. Science does not deal in proofs like mathematics. If an experiment fails to disprove a hypothesis, then we find support for that explanation, but this is not to say that down the road a better explanation will not be found, or a more carefully designed experiment will be found to falsify the hypothesis.

Each experiment will have one or more variables and one or more controls. A variable is any part of the experiment that can vary or change during the experiment. A control is a part of the experiment that does not change. Look for the variables and controls in the example that follows. As a simple example, an experiment might be conducted to test the hypothesis that phosphate limits the growth of algae in freshwater ponds. A series of artificial ponds are filled with water and half of them are treated by adding phosphate each week, while the other half are treated by adding a salt that is known not to be used by algae. The variable here is the phosphate (or lack of phosphate), the experimental or treatment cases are the ponds with added phosphate and the control ponds are those with something inert added, such as the salt. Just adding something is also a control against the possibility that adding extra matter to the pond has an effect. If the treated ponds show lesser growth of algae, then we have found support for our hypothesis. If they do not, then we reject our hypothesis. Be aware that rejecting one hypothesis does not determine whether or not the other hypotheses can be accepted; it simply eliminates one hypothesis that is not valid (Figure \(\PageIndex{5}\)). Using the scientific method, the hypotheses that are inconsistent with experimental data are rejected.

A flow chart shows the steps in the scientific method. In step 1, an observation is made. In step 2, a question is asked about the observation. In step 3, an answer to the question, called a hypothesis, is proposed. In step 4, a prediction is made based on the hypothesis. In step 5, an experiment is done to test the prediction. In step 6, the results are analyzed to determine whether or not the hypothesis is supported. If the hypothesis is not supported, another hypothesis is made. In either case, the results are reported.

Example \(\PageIndex{1}\)

In the example below, the scientific method is used to solve an everyday problem. Which part in the example below is the hypothesis? Which is the prediction? Based on the results of the experiment, is the hypothesis supported? If it is not supported, propose some alternative hypotheses.

My toaster doesn’t toast my bread.
Why doesn’t my toaster work?
There is something wrong with the electrical outlet.
If something is wrong with the outlet, my coffeemaker also won’t work when plugged into it.
I plug my coffeemaker into the outlet.
My coffeemaker works.

The hypothesis is #3 (there is something wrong with the electrical outlet), and the prediction is #4 (if something is wrong with the outlet, then the coffeemaker also won’t work when plugged into the outlet). The original hypothesis is not supported, as the coffee maker works when plugged into the outlet. Alternative hypotheses may include (1) the toaster might be broken or (2) the toaster wasn’t turned on.

In practice, the scientific method is not as rigid and structured as it might at first appear. Sometimes an experiment leads to conclusions that favor a change in approach; often, an experiment brings entirely new scientific questions to the puzzle. Many times, science does not operate in a linear fashion; instead, scientists continually draw inferences and make generalizations, finding patterns as their research proceeds. Scientific reasoning is more complex than the scientific method alone suggests.

Basic and Applied Science

The scientific community has been debating for the last few decades about the value of different types of science. Is it valuable to pursue science for the sake of simply gaining knowledge, or does scientific knowledge only have worth if we can apply it to solving a specific problem or bettering our lives? This question focuses on the differences between two types of science: basic science and applied science.

Basic science or “pure” science seeks to expand knowledge regardless of the short-term application of that knowledge. It is not focused on developing a product or a service of immediate public or commercial value. The immediate goal of basic science is knowledge for knowledge’s sake, though this does not mean that in the end it may not result in an application.

In contrast, applied science or “technology,” aims to use science to solve real-world problems, making it possible, for example, to improve a crop yield, find a cure for a particular disease, or save animals threatened by a natural disaster. In applied science, the problem is usually defined for the researcher.

Some individuals may perceive applied science as “useful” and basic science as “useless.” A question these people might pose to a scientist advocating knowledge acquisition would be, “What for?” A careful look at the history of science, however, reveals that basic knowledge has resulted in many remarkable applications of great value. Many scientists think that a basic understanding of science is necessary before an application is developed; therefore, applied science relies on the results generated through basic science. Other scientists think that it is time to move on from basic science and instead to find solutions to actual problems. Both approaches are valid. It is true that there are problems that demand immediate attention; however, few solutions would be found without the help of the knowledge generated through basic science.

One example of how basic and applied science can work together to solve practical problems occurred after the discovery of DNA structure led to an understanding of the molecular mechanisms governing DNA replication. Strands of DNA, unique in every human, are found in our cells, where they provide the instructions necessary for life. During DNA replication, new copies of DNA are made, shortly before a cell divides to form new cells. Understanding the mechanisms of DNA replication enabled scientists to develop laboratory techniques that are now used to identify genetic diseases, pinpoint individuals who were at a crime scene, and determine paternity. Without basic science, it is unlikely that applied science would exist.

Another example of the link between basic and applied research is the Human Genome Project, a study in which each human chromosome was analyzed and mapped to determine the precise sequence of DNA subunits and the exact location of each gene. (The gene is the basic unit of heredity; an individual’s complete collection of genes is his or her genome.) Other organisms have also been studied as part of this project to gain a better understanding of human chromosomes. The Human Genome Project (Figure \(\PageIndex{6}\)) relied on basic research carried out with non-human organisms and, later, with the human genome. An important end goal eventually became using the data for applied research seeking cures for genetically related diseases.

While research efforts in both basic science and applied science are usually carefully planned, it is important to note that some discoveries are made by serendipity, that is, by means of a fortunate accident or a lucky surprise. Penicillin was discovered when biologist Alexander Fleming accidentally left a petri dish of Staphylococcus bacteria open. An unwanted mold grew, killing the bacteria. The mold turned out to be Penicillium , and a new antibiotic was discovered. Even in the highly organized world of science, luck—when combined with an observant, curious mind—can lead to unexpected breakthroughs.

Reporting Scientific Work

Whether scientific research is basic science or applied science, scientists must share their findings for other researchers to expand and build upon their discoveries. Communication and collaboration within and between sub disciplines of science are key to the advancement of knowledge in science. For this reason, an important aspect of a scientist’s work is disseminating results and communicating with peers. Scientists can share results by presenting them at a scientific meeting or conference, but this approach can reach only the limited few who are present. Instead, most scientists present their results in peer-reviewed articles that are published in scientific journals. Peer-reviewed articles are scientific papers that are reviewed, usually anonymously by a scientist’s colleagues, or peers. These colleagues are qualified individuals, often experts in the same research area, who judge whether or not the scientist’s work is suitable for publication. The process of peer review helps to ensure that the research described in a scientific paper or grant proposal is original, significant, logical, and thorough. Grant proposals, which are requests for research funding, are also subject to peer review. Scientists publish their work so other scientists can reproduce their experiments under similar or different conditions to expand on the findings. The experimental results must be consistent with the findings of other scientists.

There are many journals and the popular press that do not use a peer-review system. A large number of online open-access journals, journals with articles available without cost, are now available many of which use rigorous peer-review systems, but some of which do not. Results of any studies published in these forums without peer review are not reliable and should not form the basis for other scientific work. In one exception, journals may allow a researcher to cite a personal communication from another researcher about unpublished results with the cited author’s permission.

Biology is the science that studies living organisms and their interactions with one another and their environments. Science attempts to describe and understand the nature of the universe in whole or in part. Science has many fields; those fields related to the physical world and its phenomena are considered natural sciences.

A hypothesis is a tentative explanation for an observation. A scientific theory is a well-tested and consistently verified explanation for a set of observations or phenomena. A scientific law is a description, often in the form of a mathematical formula, of the behavior of an aspect of nature under certain circumstances. Two types of logical reasoning are used in science. Inductive reasoning uses results to produce general scientific principles. Deductive reasoning is a form of logical thinking that predicts results by applying general principles. The common thread throughout scientific research is the use of the scientific method. Scientists present their results in peer-reviewed scientific papers published in scientific journals.

Science can be basic or applied. The main goal of basic science is to expand knowledge without any expectation of short-term practical application of that knowledge. The primary goal of applied research, however, is to solve practical problems.

Contributors and Attributions

Samantha Fowler (Clayton State University), Rebecca Roush (Sandhills Community College), James Wise (Hampton University). Original content by OpenStax (CC BY 4.0; Access for free at https://cnx.org/contents/b3c1e1d2-83...4-e119a8aafbdd ).

Examining The Ways Science Studies The Natural World

Science touches nearly every aspect of our modern lives, from the technology we use to the understanding we have of our own planet and universe. But what exactly is science, and how does it go about studying the natural world? Science can seem mystifying to many of us who aren’t scientists.

If you’re short on time, here’s a quick answer: Science is the systematic study of the structures and behaviors of the physical and natural world through observation and experimentation . The scientific method allows scientists to test hypotheses and build an expanding body of knowledge.

In this approximately 3000 word article, we will explore in depth how science is defined by its process of studying the natural world through empirical, testable means. We’ll examine the scientific method and its different components more closely.

We’ll also look at the various branches of science, from physics and chemistry to earth science and astronomy, and how scientists in these fields go about advancing human understanding.

Defining Science

Science is a systematic and logical approach to understanding the natural world. It is a field of study that seeks to explain natural phenomena through observation, experimentation, and analysis. By using evidence-based methods, scientists aim to uncover the underlying principles that govern the universe.

Science Seeks Naturalistic Explanations

One of the fundamental aspects of science is its commitment to naturalistic explanations. This means that scientists seek to explain phenomena using only natural causes and processes, without invoking supernatural or mystical explanations.

By relying on empirical evidence and rigorous experimentation, science aims to provide objective and verifiable explanations for the phenomena we observe.

For example, when studying the formation of stars, scientists do not attribute their origin to divine intervention or supernatural forces. Instead, they investigate physical processes such as gravitational collapse and nuclear fusion to understand how stars are born and evolve.

The Goal of Science is Knowledge and Understanding

The primary goal of science is to acquire knowledge and understanding of the natural world. Scientists are driven by curiosity and a desire to uncover the underlying principles that govern the universe.

Through systematic observation, experimentation, and analysis, they strive to increase our understanding of the world around us.

Whether it is studying the behavior of subatomic particles or exploring the depths of the ocean, scientists are constantly pushing the boundaries of human knowledge. Their discoveries not only deepen our understanding of the natural world but also pave the way for technological advancements and practical applications.

Science is a Process, Not Just Facts

Science is not just a collection of facts, but rather a process of inquiry and discovery. It is a dynamic and ever-evolving field that relies on critical thinking, skepticism, and peer review. Scientists formulate hypotheses, design experiments, collect data, and analyze results to refine our understanding of the natural world.

It is important to note that science is not infallible, and it is subject to revision based on new evidence and insights. This self-correcting nature is what makes science such a powerful tool for understanding the natural world.

As new discoveries are made and theories are refined, our understanding of the world continues to expand.

To learn more about the scientific process and its impact on society, you can visit Scientific American or National Geographic .

The Scientific Method

The scientific method is a systematic approach used by scientists to study and understand the natural world. It involves a series of steps that help researchers gather and analyze data in order to draw valid conclusions.

By following this method, scientists are able to ensure that their findings are reliable and can be replicated by others.

Making Observations

The first step in the scientific method is making observations. Scientists carefully observe the natural world, noting patterns, behaviors, and phenomena. These observations can be made through direct observation or by using instruments and technology to collect data.

For example, astronomers observe the movement of celestial bodies, while biologists may observe the behavior of animals in their natural habitats.

Forming a Hypothesis

After making observations, scientists then form a hypothesis. A hypothesis is an educated guess or prediction about a specific phenomenon or relationship. It is based on the observations made and existing scientific knowledge.

The hypothesis must be testable and falsifiable, meaning that it can be proven true or false through experimentation. For example, a scientist may hypothesize that increasing the amount of fertilizer will lead to increased plant growth.

Designing Experiments

Once a hypothesis is formed, scientists design experiments to test its validity. The experiment should be carefully designed to control variables and isolate the effect of the independent variable on the dependent variable.

The independent variable is the variable that is manipulated, while the dependent variable is the variable that is measured. In our fertilizer example, the independent variable would be the amount of fertilizer, while the dependent variable would be the plant growth.

Analyzing Results and Drawing Conclusions

After conducting the experiment, scientists analyze the results to determine if their hypothesis is supported or refuted. This involves collecting and organizing data, using statistical analysis to identify patterns or trends, and drawing conclusions based on the evidence.

If the results support the hypothesis, scientists may revise and refine their hypothesis, or they may propose new hypotheses to further explore the topic. If the results do not support the hypothesis, scientists may need to reconsider their initial assumptions and start the process again.

Branches of Science

Science is a vast field that encompasses various disciplines and branches, each focusing on different aspects of the natural world. These branches of science employ different methodologies and techniques to study and understand the phenomena around us. Here are some of the main branches of science:

Physical Sciences (Physics, Chemistry, etc.)

The physical sciences deal with the fundamental principles and properties of matter and energy. Physics, for example, examines the behavior of matter and energy in the universe. It explores concepts such as motion, forces, electricity, and magnetism.

Chemistry, on the other hand, delves into the composition, structure, properties, and changes of matter. It investigates elements, compounds, and reactions that occur between substances. Both physics and chemistry play integral roles in our understanding of the physical world and have practical applications in various fields.

Earth and Space Sciences

The Earth and space sciences focus on the study of our planet, its atmosphere, and the celestial bodies that surround us. Geology, for instance, studies the Earth’s composition, history, and the processes that shape its surface.

It encompasses the study of rocks, minerals, and the forces that cause earthquakes and volcanic eruptions. Astronomy, on the other hand, examines the universe beyond our planet. It explores galaxies, stars, planets, and other celestial objects.

This branch of science helps us understand the origins, evolution, and properties of the vast cosmos we inhabit.

Life Sciences (Biology, Ecology, etc.)

The life sciences deal with the study of living organisms and their interactions with the environment. Biology, the most well-known branch of the life sciences, explores the various aspects of life, including the structure, function, growth, and evolution of organisms.

It encompasses sub-disciplines such as genetics, microbiology, and botany. Ecology, on the other hand, focuses on the relationships between organisms and their environment. It studies the interdependence of living organisms, their habitats, and the ecosystems they form.

The life sciences play a crucial role in understanding the diversity and complexity of life on Earth.

Social Sciences

The social sciences examine human behavior, societies, and the interplay between individuals and communities. Sociology, for example, studies social interactions, institutions, and the development of societies. It explores topics such as social stratification, culture, and social change.

Psychology focuses on the human mind and behavior, seeking to understand cognitive processes, emotions, and personality. Other social sciences include anthropology, economics, political science, and geography.

These disciplines provide valuable insights into human societies, their structures, and the factors that shape them.

By studying the natural world through these different branches of science, researchers and scientists gain a deeper understanding of our universe and the intricate systems that govern it. Whether it’s unraveling the mysteries of the cosmos, exploring the complexities of life, or understanding human behavior, science helps us make sense of the world we live in.

Tools and Technology in Science

Science has made remarkable progress in understanding the natural world, thanks to the development and utilization of various tools and technologies. These advancements have significantly enhanced the accuracy and efficiency of scientific research, allowing scientists to delve deeper into their investigations.

This section will explore the different types of tools and technologies used in scientific studies.

Scientific Instruments

Scientific instruments play a crucial role in enabling scientists to observe and measure various phenomena in the natural world. These instruments are specially designed to collect data and provide precise measurements.

Examples of scientific instruments include telescopes, microscopes, spectrometers, and particle accelerators. These instruments allow scientists to explore the vastness of the universe, investigate the microscopic world, analyze the composition of substances, and even simulate conditions similar to those found in extreme environments.

Laboratory Methods and Equipment

In the controlled environment of a laboratory, scientists employ a wide range of methods and equipment to conduct their experiments. Laboratory methods involve carefully designed procedures and protocols to ensure accuracy and reproducibility.

Equipment such as centrifuges, pipettes, chromatographs, and incubators are used to perform various tasks, including separating substances, measuring volumes, analyzing chemical components, and maintaining specific conditions for biological samples.

These tools and techniques allow scientists to carry out experiments under controlled conditions, leading to reliable and precise results.

Field Research Methods

While laboratories provide controlled environments, scientists also conduct research in the field to study natural phenomena in their natural habitats. Field research methods involve direct observation, data collection, and analysis in real-world settings.

Scientists may use tools such as GPS devices, drones, underwater cameras, and weather stations to gather data. Field research allows scientists to study ecosystems, observe animal behavior, monitor environmental changes, and gather data that cannot be replicated in a laboratory.

It provides valuable insights into the dynamics of the natural world.

Computing and Data Analysis

With the advent of computing technology, scientists can now process and analyze vast amounts of data more efficiently. Computers and software programs enable scientists to organize, manipulate, and visualize data, making complex analyses more accessible.

Additionally, statistical tools and modeling software allow scientists to make predictions and draw conclusions from their data. The use of data analysis techniques, such as regression analysis, machine learning, and data mining, has revolutionized scientific research in fields ranging from genetics to climate science.

Scientific tools and technologies have revolutionized the way researchers study the natural world. These advancements have enabled scientists to explore the universe, investigate microscopic structures, analyze complex data, and conduct experiments under controlled conditions.

By leveraging these tools and technologies, scientists continue to expand our knowledge and understanding of the natural world.

Scientific Institutions and Communities

Academic and research institutions.

Academic and research institutions play a vital role in advancing scientific knowledge and understanding. These institutions, such as universities and research centers, provide the necessary infrastructure, resources, and expertise for scientists to conduct their studies.

Professors and researchers at these institutions are often at the forefront of scientific discoveries, conducting groundbreaking research in various fields.

For example, the Massachusetts Institute of Technology (MIT) is renowned for its cutting-edge research in fields like artificial intelligence and nanotechnology. The institution’s faculty members and students collaborate on projects that push the boundaries of scientific knowledge and drive innovation.

Scientific Societies and Organizations

Scientific societies and organizations bring together individuals with shared scientific interests and provide a platform for collaboration, networking, and knowledge exchange. These societies often organize conferences, symposiums, and workshops where scientists can present their research findings, discuss emerging trends, and foster interdisciplinary collaborations.

One prominent example is the American Association for the Advancement of Science (AAAS), which is the world’s largest multidisciplinary scientific society. The AAAS publishes the journal Science and organizes the annual AAAS meeting, where scientists from various fields come together to share their work and explore new avenues of research.

Science Communication and Publishing

Science communication and publishing are essential for disseminating scientific knowledge to a wider audience. Science journalists, popular science writers, and science communicators play a crucial role in translating complex scientific concepts into accessible language for the general public.

Scientific publishing houses, such as Nature and Science, provide a platform for scientists to publish their research findings in peer-reviewed journals. These journals ensure the quality and credibility of scientific research by subjecting it to rigorous scrutiny by experts in the field.

Funding and Policy

Funding and policy decisions significantly influence the direction and progress of scientific research. Government agencies, private foundations, and industry partners provide financial support for scientific studies, enabling scientists to conduct their research and develop new technologies.

For instance, the National Institutes of Health (NIH) in the United States is the largest public funder of biomedical research. Its funding supports groundbreaking discoveries in areas such as cancer research, genetics, and infectious diseases.

Policy decisions also shape the scientific landscape by setting priorities, regulations, and ethical guidelines for research. These policies ensure the responsible conduct of research and protect the rights and welfare of human subjects and animal models.

In summary, science is deeply rooted in an evidence-based process of testing natural explanations through controlled observation and experimentation. While scientific knowledge grows over time, the scientific method itself remains constant as the fundamental way of studying the diverse phenomena of the natural world.

This process of inquiry continues to expand the frontiers of human understanding through a collaborative scientific community.

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1.2 The Scientific Methods

Section learning objectives.

By the end of this section, you will be able to do the following:

Explain how the methods of science are used to make scientific discoveries
Define a scientific model and describe examples of physical and mathematical models used in physics
Compare and contrast hypothesis, theory, and law

Teacher Support

The learning objectives in this section will help your students master the following standards:

(A) know the definition of science and understand that it has limitations, as specified in subsection (b)(2) of this section;
(B) know that scientific hypotheses are tentative and testable statements that must be capable of being supported or not supported by observational evidence. Hypotheses of durable explanatory power which have been tested over a wide variety of conditions are incorporated into theories;
(C) know that scientific theories are based on natural and physical phenomena and are capable of being tested by multiple independent researchers. Unlike hypotheses, scientific theories are well-established and highly-reliable explanations, but may be subject to change as new areas of science and new technologies are developed;
(D) distinguish between scientific hypotheses and scientific theories.

Section Key Terms

[OL] Pre-assessment for this section could involve students sharing or writing down an anecdote about when they used the methods of science. Then, students could label their thought processes in their anecdote with the appropriate scientific methods. The class could also discuss their definitions of theory and law, both outside and within the context of science.

[OL] It should be noted and possibly mentioned that a scientist , as mentioned in this section, does not necessarily mean a trained scientist. It could be anyone using methods of science.

Scientific Methods

Scientists often plan and carry out investigations to answer questions about the universe around us. These investigations may lead to natural laws. Such laws are intrinsic to the universe, meaning that humans did not create them and cannot change them. We can only discover and understand them. Their discovery is a very human endeavor, with all the elements of mystery, imagination, struggle, triumph, and disappointment inherent in any creative effort. The cornerstone of discovering natural laws is observation. Science must describe the universe as it is, not as we imagine or wish it to be.

We all are curious to some extent. We look around, make generalizations, and try to understand what we see. For example, we look up and wonder whether one type of cloud signals an oncoming storm. As we become serious about exploring nature, we become more organized and formal in collecting and analyzing data. We attempt greater precision, perform controlled experiments (if we can), and write down ideas about how data may be organized. We then formulate models, theories, and laws based on the data we have collected, and communicate those results with others. This, in a nutshell, describes the scientific method that scientists employ to decide scientific issues on the basis of evidence from observation and experiment.

An investigation often begins with a scientist making an observation . The scientist observes a pattern or trend within the natural world. Observation may generate questions that the scientist wishes to answer. Next, the scientist may perform some research about the topic and devise a hypothesis . A hypothesis is a testable statement that describes how something in the natural world works. In essence, a hypothesis is an educated guess that explains something about an observation.

[OL] An educated guess is used throughout this section in describing a hypothesis to combat the tendency to think of a theory as an educated guess.

Scientists may test the hypothesis by performing an experiment . During an experiment, the scientist collects data that will help them learn about the phenomenon they are studying. Then the scientists analyze the results of the experiment (that is, the data), often using statistical, mathematical, and/or graphical methods. From the data analysis, they draw conclusions. They may conclude that their experiment either supports or rejects their hypothesis. If the hypothesis is supported, the scientist usually goes on to test another hypothesis related to the first. If their hypothesis is rejected, they will often then test a new and different hypothesis in their effort to learn more about whatever they are studying.

Scientific processes can be applied to many situations. Let’s say that you try to turn on your car, but it will not start. You have just made an observation! You ask yourself, "Why won’t my car start?" You can now use scientific processes to answer this question. First, you generate a hypothesis such as, "The car won’t start because it has no gasoline in the gas tank." To test this hypothesis, you put gasoline in the car and try to start it again. If the car starts, then your hypothesis is supported by the experiment. If the car does not start, then your hypothesis is rejected. You will then need to think up a new hypothesis to test such as, "My car won’t start because the fuel pump is broken." Hopefully, your investigations lead you to discover why the car won’t start and enable you to fix it.

A model is a representation of something that is often too difficult (or impossible) to study directly. Models can take the form of physical models, equations, computer programs, or simulations—computer graphics/animations. Models are tools that are especially useful in modern physics because they let us visualize phenomena that we normally cannot observe with our senses, such as very small objects or objects that move at high speeds. For example, we can understand the structure of an atom using models, without seeing an atom with our own eyes. Although images of single atoms are now possible, these images are extremely difficult to achieve and are only possible due to the success of our models. The existence of these images is a consequence rather than a source of our understanding of atoms. Models are always approximate, so they are simpler to consider than the real situation; the more complete a model is, the more complicated it must be. Models put the intangible or the extremely complex into human terms that we can visualize, discuss, and hypothesize about.

Scientific models are constructed based on the results of previous experiments. Even still, models often only describe a phenomenon partially or in a few limited situations. Some phenomena are so complex that they may be impossible to model them in their entirety, even using computers. An example is the electron cloud model of the atom in which electrons are moving around the atom’s center in distinct clouds ( Figure 1.12 ), that represent the likelihood of finding an electron in different places. This model helps us to visualize the structure of an atom. However, it does not show us exactly where an electron will be within its cloud at any one particular time.

As mentioned previously, physicists use a variety of models including equations, physical models, computer simulations, etc. For example, three-dimensional models are often commonly used in chemistry and physics to model molecules. Properties other than appearance or location are usually modelled using mathematics, where functions are used to show how these properties relate to one another. Processes such as the formation of a star or the planets, can also be modelled using computer simulations. Once a simulation is correctly programmed based on actual experimental data, the simulation can allow us to view processes that happened in the past or happen too quickly or slowly for us to observe directly. In addition, scientists can also run virtual experiments using computer-based models. In a model of planet formation, for example, the scientist could alter the amount or type of rocks present in space and see how it affects planet formation.

Scientists use models and experimental results to construct explanations of observations or design solutions to problems. For example, one way to make a car more fuel efficient is to reduce the friction or drag caused by air flowing around the moving car. This can be done by designing the body shape of the car to be more aerodynamic, such as by using rounded corners instead of sharp ones. Engineers can then construct physical models of the car body, place them in a wind tunnel, and examine the flow of air around the model. This can also be done mathematically in a computer simulation. The air flow pattern can be analyzed for regions smooth air flow and for eddies that indicate drag. The model of the car body may have to be altered slightly to produce the smoothest pattern of air flow (i.e., the least drag). The pattern with the least drag may be the solution to increasing fuel efficiency of the car. This solution might then be incorporated into the car design.

Using Models and the Scientific Processes

Be sure to secure loose items before opening the window or door.

In this activity, you will learn about scientific models by making a model of how air flows through your classroom or a room in your house.

One room with at least one window or door that can be opened
Work with a group of four, as directed by your teacher. Close all of the windows and doors in the room you are working in. Your teacher may assign you a specific window or door to study.
Before opening any windows or doors, draw a to-scale diagram of your room. First, measure the length and width of your room using the tape measure. Then, transform the measurement using a scale that could fit on your paper, such as 5 centimeters = 1 meter.
Your teacher will assign you a specific window or door to study air flow. On your diagram, add arrows showing your hypothesis (before opening any windows or doors) of how air will flow through the room when your assigned window or door is opened. Use pencil so that you can easily make changes to your diagram.
On your diagram, mark four locations where you would like to test air flow in your room. To test for airflow, hold a strip of single ply tissue paper between the thumb and index finger. Note the direction that the paper moves when exposed to the airflow. Then, for each location, predict which way the paper will move if your air flow diagram is correct.
Now, each member of your group will stand in one of the four selected areas. Each member will test the airflow Agree upon an approximate height at which everyone will hold their papers.
When you teacher tells you to, open your assigned window and/or door. Each person should note the direction that their paper points immediately after the window or door was opened. Record your results on your diagram.
Did the airflow test data support or refute the hypothetical model of air flow shown in your diagram? Why or why not? Correct your model based on your experimental evidence.
With your group, discuss how accurate your model is. What limitations did it have? Write down the limitations that your group agreed upon.
Yes, you could use your model to predict air flow through a new window. The earlier experiment of air flow would help you model the system more accurately.
Yes, you could use your model to predict air flow through a new window. The earlier experiment of air flow is not useful for modeling the new system.
No, you cannot model a system to predict the air flow through a new window. The earlier experiment of air flow would help you model the system more accurately.
No, you cannot model a system to predict the air flow through a new window. The earlier experiment of air flow is not useful for modeling the new system.

This Snap Lab! has students construct a model of how air flows in their classroom. Each group of four students will create a model of air flow in their classroom using a scale drawing of the room. Then, the groups will test the validity of their model by placing weathervanes that they have constructed around the room and opening a window or door. By observing the weather vanes, students will see how air actually flows through the room from a specific window or door. Students will then correct their model based on their experimental evidence. The following material list is given per group:

One room with at least one window or door that can be opened (An optimal configuration would be one window or door per group.)
Several pieces of construction paper (at least four per group)
Strips of single ply tissue paper
One tape measure (long enough to measure the dimensions of the room)
Group size can vary depending on the number of windows/doors available and the number of students in the class.
The room dimensions could be provided by the teacher. Also, students may need a brief introduction in how to make a drawing to scale.
This is another opportunity to discuss controlled experiments in terms of why the students should hold the strips of tissue paper at the same height and in the same way. One student could also serve as a control and stand far away from the window/door or in another area that will not receive air flow from the window/door.
You will probably need to coordinate this when multiple windows or doors are used. Only one window or door should be opened at a time for best results. Between openings, allow a short period (5 minutes) when all windows and doors are closed, if possible.

Answers to the Grasp Check will vary, but the air flow in the new window or door should be based on what the students observed in their experiment.

Scientific Laws and Theories

A scientific law is a description of a pattern in nature that is true in all circumstances that have been studied. That is, physical laws are meant to be universal , meaning that they apply throughout the known universe. Laws are often also concise, whereas theories are more complicated. A law can be expressed in the form of a single sentence or mathematical equation. For example, Newton’s second law of motion , which relates the motion of an object to the force applied ( F ), the mass of the object ( m ), and the object’s acceleration ( a ), is simply stated using the equation

Scientific ideas and explanations that are true in many, but not all situations in the universe are usually called principles . An example is Pascal’s principle , which explains properties of liquids, but not solids or gases. However, the distinction between laws and principles is sometimes not carefully made in science.

A theory is an explanation for patterns in nature that is supported by much scientific evidence and verified multiple times by multiple researchers. While many people confuse theories with educated guesses or hypotheses, theories have withstood more rigorous testing and verification than hypotheses.

[OL] Explain to students that in informal, everyday English the word theory can be used to describe an idea that is possibly true but that has not been proven to be true. This use of the word theory often leads people to think that scientific theories are nothing more than educated guesses. This is not just a misconception among students, but among the general public as well.

As a closing idea about scientific processes, we want to point out that scientific laws and theories, even those that have been supported by experiments for centuries, can still be changed by new discoveries. This is especially true when new technologies emerge that allow us to observe things that were formerly unobservable. Imagine how viewing previously invisible objects with a microscope or viewing Earth for the first time from space may have instantly changed our scientific theories and laws! What discoveries still await us in the future? The constant retesting and perfecting of our scientific laws and theories allows our knowledge of nature to progress. For this reason, many scientists are reluctant to say that their studies prove anything. By saying support instead of prove , it keeps the door open for future discoveries, even if they won’t occur for centuries or even millennia.

[OL] With regard to scientists avoiding using the word prove , the general public knows that science has proven certain things such as that the heart pumps blood and the Earth is round. However, scientists should shy away from using prove because it is impossible to test every single instance and every set of conditions in a system to absolutely prove anything. Using support or similar terminology leaves the door open for further discovery.

Check Your Understanding

Models are simpler to analyze.
Models give more accurate results.
Models provide more reliable predictions.
Models do not require any computer calculations.
They are the same.
A hypothesis has been thoroughly tested and found to be true.
A hypothesis is a tentative assumption based on what is already known.
A hypothesis is a broad explanation firmly supported by evidence.
A scientific model is a representation of something that can be easily studied directly. It is useful for studying things that can be easily analyzed by humans.
A scientific model is a representation of something that is often too difficult to study directly. It is useful for studying a complex system or systems that humans cannot observe directly.
A scientific model is a representation of scientific equipment. It is useful for studying working principles of scientific equipment.
A scientific model is a representation of a laboratory where experiments are performed. It is useful for studying requirements needed inside the laboratory.
The hypothesis must be validated by scientific experiments.
The hypothesis must not include any physical quantity.
The hypothesis must be a short and concise statement.
The hypothesis must apply to all the situations in the universe.
A scientific theory is an explanation of natural phenomena that is supported by evidence.
A scientific theory is an explanation of natural phenomena without the support of evidence.
A scientific theory is an educated guess about the natural phenomena occurring in nature.
A scientific theory is an uneducated guess about natural phenomena occurring in nature.
A hypothesis is an explanation of the natural world with experimental support, while a scientific theory is an educated guess about a natural phenomenon.
A hypothesis is an educated guess about natural phenomenon, while a scientific theory is an explanation of natural world with experimental support.
A hypothesis is experimental evidence of a natural phenomenon, while a scientific theory is an explanation of the natural world with experimental support.
A hypothesis is an explanation of the natural world with experimental support, while a scientific theory is experimental evidence of a natural phenomenon.

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3.1: Explaining the Natural World

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3.1.1 Aristotle: Searching for Causes

Note: Portions of the following material on Aristotle are adapted from information in The Philosophy Pages by Garth Kemerling and is licensed under a Creative Commons Attribution-ShareAlike 3.0

Aristotle (384-322 BCE) was the greatest and most influential student of Plato, whom we met in our introduction to rationalism in the Epistemology unit. Aristotle’s extensive works are marked by his gradual philosophical departure from Plato’s teachings of abstract thought about the realm of forms.

For Aristotle, logic is the means by which we come to know anything. Human knowledge seeks to establish that things have features of a certain kind. In Aristotle’s system of thought, propositions in the subject-predicate form are the primary expressions of truth about the world; they convey features or properties inherent in individual substances. He believed his logical scheme to accurately represent the true nature of reality. By beginning with simple descriptions of particular things, he thought it possible to eventually assemble the information needed for a comprehensive view of the world. Aristotle’s formal rules for correct reasoning — the basic principles of categorical logic — were universally accepted by Western philosophers until the nineteenth century.

Aristotle believed that universal truths could be known from particular things by way of induction. However, he did not consider knowledge acquired by induction to be scientific knowledge. Nevertheless, induction was a necessary preliminary to the main business of scientific enquiry, providing the primary premises required for scientific demonstrations.

Axioms , the self-evident first principles for which no proof is required, according to Aristotle, both necessitate and explain the truths of science.

Applying the principles developed in his logical treatises, Aristotle offered a general account of the operation of individual substances in the natural world. He drew a significant distinction between these two sorts of things:

those that move only when moved by something else, and
those that are capable of moving themselves.

Aristotle proposed a proper description of things of each sort, and he also attempted to explain why they function as they do. In considering bodies and their externally-produced movement, Aristotle shaped his discussion of physical science with three crucial distinctions:

Because of the difference in their origins, different accounts need to be offered for the functions of natural things and those of artifacts.
Clear distinction is needed between the basic material and the form, which jointly constitute the nature of any individual thing.
Recognition is required of the difference between things as they are and things considered in light of their ends or purposes.

With these distinctions in mind, Aristotle proposed four explanatory factors, or causes, required for having knowledge and understanding of things in the natural world:

The material cause is the basic stuff out of which the thing is made. The material cause of a house, for example, would include all the building materials. They are all part of an explanation of the house because it could not exist unless they were present in its composition.

The formal cause is the pattern or essence with which these materials conform when assembled. The formal cause of our exemplary house would be the design and structure that might be called for in its drafted plans. This, too, is part of the explanation since the materials would be only a pile of rubble (or a different house) if they were not specified in this way.

The efficient cause is the agent or force immediately responsible for bringing the material and form together to produce the thing. In the case of our house, the efficient cause would include the carpenters, masons, plumbers, and other workers who used these materials to build the house in accordance with the plans for its construction. Clearly the house would not be what it is without their contribution.

The final cause is the end or purpose for which a thing exists. For our house, the final cause would be to provide shelter for human beings. This is part of the explanation of the existence of the house, because it would not have been built unless someone needed it as a place to live.

Aristotle’s philosophy of the natural world (what we would now refer to as “philosophy of science”) claims that the world is explained by searching out the causes of natural phenomena. He believed that all four types of causes are necessary elements in any adequate account of the existence and nature of things. The absence or modification of any one of them would result it the existence of a different sort of thing. An explanation that includes all four causes completely captures the significance and reality of the thing itself.

Causation , the relationship between two events such that the first (the cause) brings about the second (the effect) has been ingrained in common thinking at least since Aristotle, though our modern conception of cause-and-effect is less complicated than Aristotle’s. As we have seen, however, the possibility of knowing that causal relationships actually exist was rejected by David Hume.

3.1.2 Bacon: Observation and Induction

Francis Bacon (1561-1626) was an Englishman with many intellectual passions: law; politics; literature; history; and philosophy, including topics related to acquiring knowledge of the natural world. Among his other viewpoints that were revolutionary for his times, Bacon took exception to the prevailing Aristotelean preference for deduction over induction as the certain path to knowledge. Further, Bacon rejected the conception of natural philosophy (science!) as an understanding of necessary causes.

Bacon was an empiricist who believed that acquiring knowledge of the natural world must proceed inductively:

first, making recurring and exhaustive observations, collecting as many facts as possible.
and then drawing conclusions that generalize the findings from specific observations.

His method — proceeding from copious observation to formulation of a theory — became a predominant method for doing science during Bacon’s own time and had influence for centuries that followed.

Objections to Bacon’s method for doing science include these criticisms:

Induction does not bring the level of certainty we seek in science.
There is no clarity as to when enough observation and investigation has occurred to finally arrive at a generalized conclusion.
The slow and plodding pace at which the method proceeds does not accommodate the spontaneous and visionary process that often leads to new scientific knowledge.

A supplemental resource is available (bottom of page) on Bacon’s use of induction.

The following video reinforces the important role that creative ideas play in furthering scientific knowledge. It also serves as a good transition to the next topic.

How simple ideas lead to scientific discoveries [CC-BY-NC-ND]

3.1.3 Working from Hypotheses

Is moving from observations to formulating a theory the only method for doing science? As demonstrated in Adam Savage’s TED-Ed video, scientific progress often starts with imagination and creative ideas (hypotheses) that influence the direction for observations, fact gathering, and testing. The Hypothetico-Deductive (H-D) method (or simply “the hypothetical method”) is a different model for the process of scientific discovery.

The process involves formulation of a testable hypothesis that could conceivably be falsified by observable data. If an observation or a test does run contrary to the predictions of the hypothesis, then the hypothesis is falsified; it must be rejected or reformulated.

Recall the valid argument form modus tollens from our Logic Unit, letting H=hypothesis, E=expected result:

If H, then E

On the other hand, if a test or observation does meet predicted expectations, this compatible outcome strengthens the hypothesis and lends it credibility, but it does not confirm it. Recall the fallacy of affirming-the-consequent from the Logic Unit; this fallacy is committed when the expected result (consequent) of an implication occurs and the arguer claims the antecedent to be true. The occurrence of the expected result cannot provide logical certainty. Some other hypothesis might be capable of creating the same result:

But expected results are steps forward. Every new test/observation found to meet expected results adds to the strength of the hypothesis. When no test is found to falsify the hypothesis, it may become accepted, at least tentatively, as a theory.

It’s important to point out that observations (empirically acquired facts) are not devalued by this method, they are essential, just a they are with inductive generalizations. Initial (or early) hypotheses (potential theories) may precede and set the direction for observations and experiments. The initial problem or question addressed by the hypothesis was most likely sparked initially by some observations.

In the next section, among other topics, we will look more closely at falsifiability and tentative acceptance of hypotheses and theories.

A supplemental resource is available (bottom of page) on the scientific method.

3.1.4 Scientific Methods Summarized

The interplay of hypothesizing, observing and testing, reformulating hypotheses, and so forth, suggests that there may be no single, universal scientific method, especially one that might fit the multitude of scientific disciplines. Specific disciplines have particular steps and methods for doing science. There may be not be a distinct, universal process. But as philosophers of science we might expect certain basic activities to take place.

Induction and Generalization

Accumulation of as many observed facts as possible concerning the topic under investigation.
Generalization from the particular observations that infer a general theory from accumulated particular facts.
Repeated accumulation of more particular facts to assess if the generalization continues to hold true. The more particular instances, the more confirmation and the higher the probability of the correctness of the generalization-based theory.

Hypothetical Method

Recognition/identification of a problem or question requiring investigation. This step probably involved prior empirical observations.
Proposal of a hypothesis that explains the problem or answers the question and is capable of being verified by empirical means.
Verification of the hypotheses through empirical activities including observations, experiments, or tests.
If any verification step falsifies the hypotheses, a return to step 2, a new hypothesis, is required.
If verification steps repeatedly support/strengthen the hypothesis, it may be accepted, at least tentatively, as a theory.

Compare Bacon’s method of generalization with the hypothetical method in terms of their respective emphases on and use of (1) induction versus deduction (2) reason vs experience. (100-200 words)

Note: Submit your response to the appropriate Assignments folder.

Supplemental Resources

Internet Encyclopedia of Philosophy (IEP) Francis Bacon . Read section 2.k on Induction, This link should take you to that location.

Scientific Method

Stanford Encyclopedia of Philosophy (SEP) Scientific Method . Read the introduction and section 1 and section 6 , through 6.1.

Aristotle (384-322 BCE). Authored by : Garth Kemerling . Provided by : Philosophy Pages. Located at : http://www.philosophypages.com/ph/aris.htm . License : CC BY-SA: Attribution-ShareAlike
3.1 Explaining the Natural World. Authored by : Kathy Eldred. Provided by : Pima Community College. License : CC BY: Attribution

Part I: Humans and the Ecological Environment

Chapter 2 ~ science as a way of understanding the natural world, key concepts.

After completing this chapter, you will be able to

Describe the nature of science and its usefulness in explaining the natural world.
Distinguish among facts, hypotheses, and theories.
Outline the methodology of science, including the importance of tests designed to disprove hypotheses.
Discuss the importance of uncertainty in many scientific predictions, and the relevance of this to environmental controversies.

The Nature of Science

Science can be defined as the systematic examination of the structure and functioning of the natural world, including both its physical and biological attributes. Science is also a rapidly expanding body of knowledge, whose ultimate goal is to discover the simplest general principles that can explain the enormous complexity of nature. These principles can be used to gain insights about the natural world and to make predictions about future change.

Modern science began with the systematic investigations of famous 16th- and 17th-century scientists, such as:

Nicolaus Copernicus (1473-1543), a Polish astronomer who conceived the modern theory of the solar system
William Gilbert (1544-1603), an Englishman who worked on magnetism
Galileo Galilei (1564-1642), an Italian who conducted research on the physics of objects in motion, as well as astronomy
William Harvey (1578-1657), an Englishman who described the circulation of the blood
Isaac Newton (1642-1727), an Englishman who made important contributions to understanding gravity and the nature of light, formulated laws of motion, and developed the mathematics of calculus

Inductive and Deductive Logic

The English philosopher Francis Bacon (1561-1626) was also highly influential in the development of modern science. Bacon was not an actual practitioner of science but was a strong proponent of its emerging methodologies. He promoted the application of inductive logic, in which conclusions are developed from the accumulating evidence of experience and the results of experiments. Inductive logic can lead to unifying explanations based on large bodies of data and observations of phenomena (Figure 2.1). Consider the following example of inductive logic, applied to an environmental topic:

Observation 1: Marine mammals off the Atlantic coast of North America have large residues of DDT and other chlorinated hydrocarbons in their fat and other body tissues.
Observation 2: So do marine mammals off the Pacific coast.
Observation 3: As do those in the Arctic Ocean, although in lower concentrations.

Inductive conclusion: There is a widespread contamination of marine mammals with chlorinated hydrocarbons. Further research may demonstrate that contamination is a global phenomenon. This suggests a potentially important environmental problem.

Assumption 1: TCDD, an extremely toxic chemical in the dioxin family, is poisonous when present in even the smallest concentrations in food and water—even a single molecule can cause toxicity.
Assumption 2: Exposure to anything that is poisonous in even the smallest concentrations is unsafe.
Assumption 3: No exposure that is unsafe should be allowed.

Deductive conclusion 1: No exposure to TCDD is safe.

Deductive conclusion 2: No emissions of TCDD should be allowed.

The two conclusions are consistent with the original assumptions. However, there is disagreement among highly qualified scientists about those assumptions. Many toxicologists believe that exposures to TCDD (and any other potentially toxic chemicals) must exceed a threshold of biological tolerance before poisoning will result (see Chapter 19). In contrast, other scientists believe that even the smallest exposure to TCDD carries some degree of toxic risk. Thus, the strength of deductive logic depends on the acceptance and truth of the original assumptions from which its conclusions flow.

Figure 2.1 Deductive and Inductive Reasoning in Science. Making sense of the natural world begins with observations. Left) As we collect observations of the world, we can begin to make general predictions (or perceptions) regarding phenomena. This process is known as inductive reasoning, making general predictions from specific phenomena. From these generalized perceptions of reality, specific predictions can be deduced using logic, generating hypotheses. Middle) Experimentation allows researchers to test the predictions of the hypotheses. If a hypothesis is falsified, that is another observation which adds to our general perception of reality. Right) As more and more similar but different experiments reinforce a specific prediction, growing support emerges for the development of a scientific theory, another example of inductive reasoning. In turn, a theory can assist in the development of additional, untested hypotheses using deductive reasoning. S ource: used with permission from Jason Walker, The Biolog y Primer .

Goals of Science

A higher goal of scientific research is to formulate laws that describe the workings of the universe in general terms. (For example, see Chapter 3 for a description of the laws of thermodynamics, which deal with the transformations of energy among its various states.) Universal laws, along with theories and hypotheses (see below), are used to understand and explain natural phenomena. However, many natural phenomena are extremely complex and may never be fully understood in terms of physical laws. This is particularly true of the ways that organisms and ecosystems are organized and function.

Facts, Hypotheses, and Experiments

The theory of gravitation, first proposed by Isaac Newton (1642-1727)
The theory of evolution by natural selection, published simultaneously in 1858 by two English naturalists, Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913)
The theory of relativity, identified by the German–Swiss physicist, Albert Einstein (1879-1955)

Celebrated theories like these are strongly supported by large bodies of evidence, and they will likely persist for a long time. However, we cannot say that these (or any other) theories are known with certainty to be true – some future experiments may yet falsify even these famous theories.

The scientific method begins with the identification of a question involving the structure or function of the natural world, which is usually developed using inductive logic (Figure 2.2). The question is interpreted in terms of existing theory, and specific hypotheses are formulated to explain the character and causes of the natural phenomenon. The research might involve observations made in nature, or carefully controlled experiments, and the results usually give scientists reasons to reject hypotheses rather than to accept them. Most hypotheses are rejected because their predictions are not borne out during the course of research. Any viable hypotheses are further examined through additional research, again largely involving experiments designed to disprove their predictions. Once a large body of evidence accumulates in support of a hypothesis, it can be used to corroborate the original theory.

Figure 2.2. Diagrammatic Representation of the Scientific Method. The scientific method starts with a question, relates that question to a theory, formulates a hypothesis, and then rigorously tests that hypothesis. Source: Modified from Raven and Johnson (1992).

The scientific method is only used to investigate questions that can be critically examined through observation and experiment. Consequently, science cannot resolve value-laden questions, such as the meaning of life, good versus evil, or the existence and qualities of God or any other supernatural being or force.

A variable is a factor that is believed to influence a natural phenomenon. For example, a scientist might hypothesize that the productivity of a wheat crop is potentially limited by such variables as the availability of water or of nutrients such as nitrogen and phosphorus. Some of the most powerful scientific experiments involve the manipulation of key (or controlling) variables and the comparison of results of those treatments with a control that was not manipulated. In the example just described, the specific variable that controls wheat productivity could be identified by conducting an experiment in which test populations are provided with varying amounts of water, nitrogen, and phosphorus, alone and in combination, and then comparing the results with a non-manipulated control.

Image 2.1. An experiment is a controlled investigation designed to provide evidence for, or preferably against, a hypothesis about the working of the natural world. This laboratory experiment exposed test populations of a grass to different concentrations of a toxic chemical. B. Freeman.

Uncertainty

Predictability

However, most natural phenomena are not so consistent – depending on circumstances, there are exceptions to general predictions about them. This circumstance is particularly true of biology and ecology, related fields of science in which almost all general predictions have exceptions. In fact, laws or unifying principles of biology or ecology have not yet been discovered, in contrast to the several esteemed laws and 11 universal constants of physics. For this reason, biologists and ecologists have great difficulties making accurate predictions about the responses of organisms and ecosystems to environmental change. This is why biologists and ecologists are sometimes said to have “physics envy.”

In large part, the inaccuracies of biology and ecology occur because key functions are controlled by poorly understood, and sometimes unidentified, environmental influences. Consequently, predictions about future values of biological and ecological variables or the causes of changes are seldom accurate. For example, even though ecologists in North America have been monitoring the population size of spruce budworm (an important pest of conifer forests) for some years, they cannot accurately predict its future abundance in particular stands of forest or in larger regions. This is because the abundance of this moth is influenced by a variety of environmental factors, including tree-species composition, age of the forest, abundance of its predators and parasites, quantities of its preferred foods, weather at critical times of year, and insecticide use to reduce its populations (see Chapter 26). Biologists and ecologists do not fully understand this complexity, and perhaps they never will.

Variability

Accuracy and Precision

Precision is related to the degree of repeatability of a measurement or observation. For example, suppose that the actual number of caribou in a migrating herd is 10,246 animals. A wildlife ecologist might estimate that there were about 10,000 animals in that herd, which for practical purposes is a reasonably accurate reckoning of the actual number of caribou. If other ecologists also independently estimate the size of the herd at about 10,000 caribou, there is a good degree of precision among the values. If, however, some systematic bias existed in the methodology used to count the herd, giving consistent estimates of 15,000 animals (remember, the actual population is 10,246 caribou), these estimates would be considered precise, but not particularly accurate.

Precision is also related to the number of digits with which data are reported. If you were using a flexible tape to measure the lengths of 10 large, wriggly snakes, you would probably measure the reptiles only to the nearest centimeter. The strength and squirminess of the animals make more precise measurements impossible. The reported average length of the 10 snakes should reflect the original measurements and might be given as 204 cm and not a value such as 203.8759 cm. The latter number might be displayed as a digital average by a calculator or computer, but it is unrealistically precise.

Significant figures are related to accuracy and precision and can be defined as the number of digits used to report data from analyses or calculations. Significant figures are most easily understood by examples. The number 179 has three significant figures, as does the number 0.0849 and also 0.000794 (the zeros preceding the significant integers do not count). However, the number 195,000,000 has nine significant figures (the zeros following are meaningful), although the number 195 × 10 6 has only three significant figures.

It is rarely useful to report environmental or ecological data to more than 2-4 significant figures. This is because any more would generally exceed the accuracy and precision of the methodology used in the estimation and would therefore be unrealistic. For example, the approximate population of the United States in 2020 was 330 million people, which uses three significant figures. However, the population should not be reported as 330,000,000, which implies an unrealistic accuracy and precision of nine significant figures.

A Need for Skepticism

Environmental science is filled with many examples of uncertainty– in present values and future changes of environmental variables, as well as in predictions of biological and ecological responses to those changes. To some degree, the difficulties associated with scientific uncertainty can be mitigated by developing improved methods and technologies for analysis and by modelling and examining changes occurring in different parts of the world. The latter approach enhances our understanding by providing convergent evidence about the occurrence and causes of natural phenomena.

Scientific information is, however, only one consideration for decision makers, who are also concerned with the economic, cultural, and political contexts of environmental problems (see Environmental Issues 1.1). In fact, when deciding how to deal with the causes and consequences of environmental changes, decision makers may give greater weight to non-scientific (social and economic) considerations than to scientific ones, especially when there is uncertainty about the latter. The most important decisions about environmental issues are made by politicians and senior bureaucrats in government, or by private managers, rather than by environmental scientists. Decision makers typically worry about the short-term implications of their decisions on their chances for re-election or continued employment, and on the economic activity of a company or society at large, as much as they do about the consequences of environmental damage.

In Detail 2.1. Critical Evaluation of an Overload of Information

More so than any previous society, we live today in a world of easy and abundant information. It has become remarkably easy for people to communicate with others over vast distances, turning the world into a “global village” (a phrase coined by Marshall McLuhan (1911-1980), a Canadian philosopher, to describe the phenomenon of universal networking). This global connectedness has been facilitated by technologies for transferring ideas and knowledge—particularly electronic communication devices, such as radio, television, computers, and their networks. Today, these technologies compress space and time to achieve a virtually instantaneous communication. In fact, so much information is now available that the situation is often referred to as an “information overload” that must be analyzed critically. Critical analysis is the process of sorting information and making scientific enquiries about data. Involved in all aspects of the scientific process, critical analysis scrutinizes information and research by posing sensible questions such as the following:

Is the information derived from a scientific framework consisting of a hypothesis that has been developed and tested, within the context of an existing body of knowledge and theory in the field?
Were the methodologies used likely to provide data that are objective, accurate, and precise? Were the data analyzed by statistical methods that are appropriate to the data structure and to the questions being asked?
Were the results of the research compared with other pertinent work that has been previously published? Were key similarities and differences discussed and a conclusion deduced about what the new work reveals about the issue being investigated?
Is the information based on research published in a refereed journal—one that requires highly qualified reviewers in the subject area to scrutinize the work, followed by an editorial decision about whether it warrants publication?
If the analysis of an issue was based on incomplete or possibly inaccurate information, was a precautionary approach used in order to accommodate the uncertainty inherent in the recommendations? All users of published research have an obligation to critically evaluate what they are reading in these ways in order to decide whether the theory is appropriate, the methodologies reliable, and the conclusions sufficiently robust. Because so many environmental issues are controversial, with data and information presented on both sides of the debate, people need to be able to formulate objectively critical judgments. For this reason, people need a high degree of environmental literacy– an informed understanding of the causes and consequences of environmental damages. Being able to critically analyze information is a key personal benefit of studying environmental science.

Conclusions

The procedures and methods of science are important in identifying, understanding, and resolving environmental problems. At the same time, however, social and economic issues are also vital considerations. Although science has made tremendous progress in helping us to understand the natural world, the extreme complexity of biology and ecosystems makes it difficult for environmental scientists to make reliable predictions about the consequences of many human economic activities and other influences. This context underscores the need for continued study of the scientific and socio-economic dimensions of environmental problems, even while practical decisions must be made to deal with obvious issues as they arise.

Questions for Review

Outline the reasons why science is a rational way of understanding the natural world.
What are the differences between inductive and deductive logic? Why is inductive logic more often used by scientists when formulating hypotheses and generalizations about the natural world?
Why are null hypotheses an efficient way to conduct scientific research? Identify a hypothesis that is suitable for examining a specific problem in environmental science and suggest a corresponding null hypothesis that could be examined through research.
What are the causes of variation in natural phenomena? Choose an example, such as differences in the body weights of a defined group of people, and suggest reasons for the variation.

Questions for Discussion

What are the key differences between science and a less objective belief system, such as religion?
What factors result in scientific controversies about environmental issues? Contrast these with environmental controversies that exist because of differing values and world views.
Explain why there are no scientific “laws” to explain the structure and function of ecosystems.
Many natural phenomena are highly variable, particularly ones that are biological or ecological. What are the implications of this variability for understanding and predicting the causes and consequences of environmental changes? How do environmental scientists cope with this challenge of a variable natural world?

Exploring Issues

Devise an environmental question of interest to yourself. Suggest useful hypotheses to investigate, identify the null hypotheses, and outline experiments that you might conduct to provide answers to this question.
During a research project investigating mercury, an environmental scientist performed a series of chemical analyses of fish caught in Lake Erie. The sampling program involved seven species of fish obtained from various habitats within the lake. A total of 360 fish of various sizes and sexes were analyzed. It was discovered that 30% of the fish had residue levels greater than 0.15 ppm of mercury, the upper level of contamination recommended by the United States Environmental Protection Agency for fish eaten by humans. The scientist reported these results to a governmental regulator, who was alarmed by the high mercury residues because of Lake Erie’s popularity as a place where people fish for food. The regulator asked the scientist to recommend whether it was safe to eat any fish from the lake or whether to avoid only certain sizes, sexes, species, or habitats. What sorts of data analyses should the scientist perform to develop useful recommendations? What other scientific and non-scientific aspects should be considered?

References Cited and Further Reading

American Association for the Advancement of Science (AAAS). 1990. Science for All Americans. AAAS, Washington, DC.

Barnes, B. 1985. About Science. Blackwell Ltd ,London, UK.

Giere, R.N. 2005. Understanding Scientific Reasoning. 5th ed. Wadsworth Publishing, New York, NY.

Kuhn, T.S. 1996. The Structure of Scientific Revolutions. 3rd ed. University of Chicago Press, Chicago, IL.

McCain, G. and E.M. Siegal. 1982. The Game of Science. Holbrook Press Inc., Boston, MA.

Moore, J.A. 1999. Science as a Way of Knowing. Harvard University Press, Boston, MA.

Popper, K. 1979. Objective Knowledge: An Evolutionary Approach. Clarendon Press, Oxford, UK.

Raven, P.H., G.B. Johnson, K.A. Mason, and J. Losos. 2013. Biology. 10th ed. McGraw-Hill, Columbus, OH.

Silver, B.L. 2000. The Ascent of Science. Oxford University Press, Oxford, UK.

Environmental Science. Authored by : Bill Freedman. Provided by : Dalhousie University. Located at : https://digitaleditions.library.dal.ca/environmentalscience/ . License : CC BY-NC: Attribution-NonCommercial

The beginnings of modern science shaped how philosophers saw alien life – and how we understand it today

Emeritus Professor in the History of Religious Thought, The University of Queensland

Disclosure statement

Philip C. Almond does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

University of Queensland provides funding as a member of The Conversation AU.

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Speculation about extraterrestrials is not all that new. There was a vibrant debate in 17th-century Europe about the existence of life on other planets.

This was the consequence of the transition from a Ptolemaic view , in which Earth was at the centre of the universe and everything revolved around it, to a Copernican view in which the Sun was at the centre and our planet, along with all the others, revolved around it.

It followed that if we were now more like other planets and moons close to us that revolved around the Sun, then they were more like Earth. And if other planets were like Earth, then they most likely also had inhabitants.

Robert Burton’s remarks in his The Anatomy of Melancholy (1621) were common:

If the Earth move, it is a Planet, and shines to them in the Moone, and to the other Planitary inhabitants, as the Moone and they doe to us upon the Earth.

Similarly, the Dutch astronomer Christiaan Huygens (1629–95) believed life on other planets was a consequence of the Sun-centred view of Copernicus. But his speculation on such matters proceeded from the doctrine of the “ divine plenitude ”. This was the belief that, in his all-powerfulness and goodness, having created matter in all parts of the universe, God would not have missed the opportunity to populate the whole universe with living beings.

In his The Celestial Worlds Discover’d (1698), Huygens suggested that, like us, the inhabitants of other planets would have hands, feet and an upward stance. However, in keeping with the greater size of other planets, particularly Jupiter and Saturn, they might be much larger than us. They would enjoy social lives, live in houses, make music, contemplate the works of God, and so on.

Others were much less confident in speculating on the nature of alien lives. Nevertheless, as Joseph Glanvill, a member of the Royal Society alongside Isaac Newton, suggested in 1676, even though details of life on other planets were unknown, this did not prejudice “the Hypothesis of the Moon’s being habitable; or the supposal of its being actually inhabited”.

That other worlds were inhabited also seemed an appropriate conclusion to draw from early modern science focused, as it was, on God’s work in nature.

This was a theme developed at length by the most influential work on the plurality of worlds in the latter part of the 17th century, the Copernican Bernard Fontenelle’s Entretiens sur la pluralité des mondes (Conversations on the Plurality of Worlds, 1686).

To Fontenelle, there was an infinite number of planets and an infinite number of inhabited worlds. For him, this was the result of the analogy, as a consequence of Copernicanism, between the nature of our Earth and that of other worlds.

But it was also the result of the fecundity of the divine being from whom all things proceed. It is this idea “of the infinite Diversity that Nature ought to use in her Works” which governs his book, he declared.

Read more: Chariots of the gods, ships in the sky: how unidentified aerial phenomena left their mark in ancient cultures

The seed of Adam

But there was a significant problem. If there were intelligent beings on the Moon or the planets, were they “men”? And, if they were, had they been redeemed by the work of Jesus Christ as people on Earth had been?

John Wilkins (1614–72), one of the founders of the new science, wrestled with the theological implications of the Copernican universe. He was convinced the Moon was inhabited. But he was quite uncertain whether the lunar residents were of “the seed of Adam”.

Wilkins’s simple solution was to deny their human status. The inhabitants of the Moon, he suggested in his The Discovery of a World in the Moone (1638), “are not men as wee are, but some other kinde of creatures which beare some proportion and likenesse to our natures”.

In the end, Fontenelle was also to adopt this solution. It would be “a great perplexing point in Theology,” he declared, should the Moon be inhabited by men not descended from Adam. He only wished to argue, he wrote, for inhabitants “which, perhaps, are not Men”.

The existence of aliens – human, just like us – threatened the credibility of the Christian story of the redemption of all humans through the life, death and resurrection of Jesus Christ. This was intellectual space in which only the theologically brave – or foolish – dared to travel.

It was much easier to reject the humanity of the alien. Thus, our modern belief that aliens are not like us originated as the solution to a theological problem. They became “alien”, literally and metaphorically. And, therefore, threatening and to be feared.

A product of the divine?

We no longer live in a universe that is seen as the product of the divine plenitude. Nor one in which our planet can be viewed as the centre of the universe. As a result, ironically, we have become aliens to ourselves: modern “alienation” is that sense of being lost and forsaken in the vast spaces of a godless universe.

In the early modern period, aliens were not looked upon as threatening to us. They were, after all (even if they were not “men”), the product of divine goodness. But, in the modern world, they both personify and externalise the threat to our personal meaning, one that results from our being in a world without ultimate meaning or purpose.

As projections of our own alienation, they terrify us, even as they continue to fascinate us.

Read more: For 600 years the Voynich manuscript has remained a mystery. Now we think it's partly about sex

Extraterrestrial life
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Chapter 2 ~ Science as a Way of Understanding the Natural World

Key concepts.

After completing this chapter, you will be able to

Describe the nature of science and its usefulness in explaining the natural world.
Distinguish among facts, hypotheses, and theories.
Outline the methodology of science, including the importance of tests designed to disprove hypotheses.
Discuss the importance of uncertainty in many scientific predictions, and the relevance of this to environmental controversies.

The Nature of Science

Modern science began with the systematic investigations of famous 16th- and 17th-century scientists, such as:

Nicolaus Copernicus (1473-1543), a Polish astronomer who conceived the modern theory of the solar system
William Gilbert (1544-1603), an Englishman who worked on magnetism
Galileo Galilei (1564-1642), an Italian who conducted research on the physics of objects in motion, as well as astronomy
William Harvey (1578-1657): an Englishman who described the circulation of the blood
Isaac Newton (1642-1727): an Englishman who made important contributions to understanding gravity and the nature of light, formulated laws of motion, and developed the mathematics of calculus

Inductive and Deductive Logic

Observation 1: Marine mammals off the Atlantic coast of Canada have large residues of DDT and other chlorinated hydrocarbons in their fat and other body tissues.
Observation 2: So do marine mammals off British Columbia.
Observation 3: As do those in the Arctic Ocean, although in lower concentrations.

Assumption 1: TCDD, an extremely toxic chemical in the dioxin family, is poisonous when present in even the smallest concentrations in food and water—even a single molecule can cause toxicity.
Assumption 2: Exposure to anything that is poisonous in even the smallest concentrations is unsafe.
Assumption 3: No exposure that is unsafe should be allowed.

Deductive conclusion 1: No exposure to TCDD is safe. Deductive conclusion 2: No emissions of TCDD should be allowed.

Goals of Science

Facts, Hypotheses, and Experiments

the theory of gravitation, first proposed by Isaac Newton (1642-1727)
the theory of evolution by natural selection, published simultaneously in 1858 by two English naturalists, Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913)
the theory of relativity, identified by the German–Swiss physicist, Albert Einstein (1879-1955)

Figure 2.1. Diagrammatic Representation of the Scientific Method. The scientific method starts with a question, relates that question to a theory, formulates a hypothesis, and then rigorously tests that hypothesis. Source: Modified from Raven and Johnson (1992).

Image 2.1. An experiment is a controlled investigation designed to provide evidence for, or preferably against, a hypothesis about the working of the natural world. This laboratory experiment exposed test populations of a grass to different concentrations of a toxic chemical.

Uncertainty

Predictability

Variability

Accuracy and Precision

A Need for Scepticism

In Detail 2.1. Critical Evaluation of an Overload of Information More so than any previous society, we live today in a world of easy and abundant information. It has become remarkably easy for people to communicate with others over vast distances, turning the world into a “global village” (a phrase coined by Marshall McLuhan (1911-1980), a Canadian philosopher, to describe the phenomenon of universal networking). This global connectedness has been facilitated by technologies for transferring ideas and knowledge—particularly electronic communication devices, such as radio, television, computers, and their networks. Today, these technologies compress space and time to achieve a virtually instantaneous communication. In fact, so much information is now available that the situation is often referred to as an “information overload” that must be analyzed critically. Critical analysis is the process of sorting information and making scientific enquiries about data. Involved in all aspects of the scientific process, critical analysis scrutinizes information and research by posing sensible questions such as the following: Is the information derived from a scientific framework consisting of a hypothesis that has been developed and tested, within the context of an existing body of knowledge and theory in the field? Were the methodologies used likely to provide data that are objective, accurate, and precise? Were the data analyzed by statistical methods that are appropriate to the data structure and to the questions being asked? Were the results of the research compared with other pertinent work that has been previously published? Were key similarities and differences discussed and a conclusion deduced about what the new work reveals about the issue being investigated? Is the information based on research published in a refereed journal—one that requires highly qualified reviewers in the subject area to scrutinize the work, followed by an editorial decision about whether it warrants publication? If the analysis of an issue was based on incomplete or possibly inaccurate information, was a precautionary approach used in order to accommodate the uncertainty inherent in the recommendations? All users of published research have an obligation to critically evaluate what they are reading in these ways in order to decide whether the theory is appropriate, the methodologies reliable, and the conclusions sufficiently robust. Because so many environmental issues are controversial, with data and information presented on both sides of the debate, people need to be able to formulate objectively critical judgments. For this reason, people need a high degree of environmental literacy—an informed understanding of the causes and consequences of environmental damages. Being able to critically analyze information is a key personal benefit of studying environmental science.

Conclusions

Questions for Review

Outline the reasons why science is a rational way of understanding the natural world.
What are the differences between inductive and deductive logic? Why is inductive logic more often used by scientists when formulating hypotheses and generalizations about the natural world?
Why are null hypotheses an efficient way to conduct scientific research? Identify a hypothesis that is suitable for examining a specific problem in environmental science and suggest a corresponding null hypothesis that could be examined through research.
What are the causes of variation in natural phenomena? Choose an example, such as differences in the body weights of a defined group of people, and suggest reasons for the variation.

Questions for Discussion

What are the key differences between science and a less objective belief system, such as religion?
What factors result in scientific controversies about environmental issues? Contrast these with environmental controversies that exist because of differing values and world views.
Explain why there are no scientific “laws” to explain the structure and function of ecosystems.
Many natural phenomena are highly variable, particularly ones that are biological or ecological. What are the implications of this variability for understanding and predicting the causes and consequences of environmental changes? How do environmental scientists cope with this challenge of a variable natural world?

Exploring Issues

Devise an environmental question of interest to yourself. Suggest useful hypotheses to investigate, identify the null hypotheses, and outline experiments that you might conduct to provide answers to this question.
During a research project investigating mercury, an environmental scientist performed a series of chemical analyses of fish caught in Lake Canuck. The sampling program involved seven species of fish obtained from various habitats within the lake. A total of 360 fish of various sizes and sexes were analyzed. It was discovered that 30% of the fish had residue levels greater than 0.5 ppm of mercury, the upper level of contamination recommended by Health Canada for fish eaten by humans. The scientist reported these results to a governmental regulator, who was alarmed by the high mercury residues because of Lake Canuck’s popularity as a place where people fish for food. The regulator asked the scientist to recommend whether it was safe to eat any fish from the lake or whether to avoid only certain sizes, sexes, species, or habitats. What sorts of data analyses should the scientist perform to develop useful recommendations? What other scientific and non-scientific aspects should be considered?

References Cited and Further Reading

American Association for the Advancement of Science (AAAS). 1990. Science for All Americans. AAAS, Washington, DC.

Barnes, B. 1985. About Science. Blackwell Ltd ,London, UK.

Giere, R.N. 2005. Understanding Scientific Reasoning. 5th ed. Wadsworth Publishing, New York, NY.

Kuhn, T.S. 1996. The Structure of Scientific Revolutions. 3rd ed. University of Chicago Press, Chicago, IL.

McCain, G. and E.M. Siegal. 1982. The Game of Science. Holbrook Press Inc., Boston, MA.

Moore, J.A. 1999. Science as a Way of Knowing. Harvard University Press, Boston, MA.

Popper, K. 1979. Objective Knowledge: An Evolutionary Approach. Clarendon Press, Oxford, UK.

Raven, P.H., G.B. Johnson, K.A. Mason, and J. Losos. 2013. Biology. 10th ed. McGraw-Hill, Columbus, OH.

Silver, B.L. 2000. The Ascent of Science. Oxford University Press, Oxford, UK.

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1.2: Science as a Way of Understanding the Natural World
Facts, Hypotheses, and Experiments. A fact is an event or thing that is definitely known to have happened, to exist, and to be true.Facts are based on experience and scientific evidence. In contrast, a hypothesis is a proposed explanation for the occurrence of a phenomenon.Scientists formulate hypotheses as statements and then test them through experiments and other forms of research.
2: Science as a Way of Understanding the Natural World
Thomas Kuhn (1922-1995) was a philosopher of science who emphasized the important role of "scientific revolutions" in achieving great advances in our understanding of the natural world. In essence, Kuhn (1996) said that a scientific revolution occurs when a well-established theory is rigorously tested and then collapses under the ...
The Nature of Science
Scientists seek to understand the natural world. Scientists begin with a question and then try to answer the question with evidence and logic. A scientific question must be testable. ... To support or refute a hypothesis, the scientist must collect data. A great deal of logic and effort goes into designing tests to collect data so the data can ...
A Guide to Using the Scientific Method in Everyday Life
The scientific method—the process used by scientists to understand the natural world—has the merit of investigating natural phenomena in a rigorous manner. Working from hypotheses, scientists draw conclusions based on empirical data. These data are validated on large-scale numbers and take into consideration the intrinsic variability of the real world.
Scientific hypothesis
hypothesis. science. scientific hypothesis, an idea that proposes a tentative explanation about a phenomenon or a narrow set of phenomena observed in the natural world. The two primary features of a scientific hypothesis are falsifiability and testability, which are reflected in an "If…then" statement summarizing the idea and in the ...
The scientific method (article)
At the core of biology and other sciences lies a problem-solving approach called the scientific method. The scientific method has five basic steps, plus one feedback step: Make an observation. Ask a question. Form a hypothesis, or testable explanation. Make a prediction based on the hypothesis. Test the prediction.
1.2 The Process of Science
Like geology, physics, and chemistry, biology is a science that gathers knowledge about the natural world. Specifically, biology is the study of life. The discoveries of biology are made by a community of researchers who work individually and together using agreed-on methods. In this sense, biology, like all sciences is a social enterprise like ...
Testing scientific ideas
Testing hypotheses and theories is at the core of the process of science. Any aspect of the natural world could be explained in many different ways. ... Hypothesis 1: Eniwetok might have originally grown around a volcanic island, which then sunk beneath the surface of the water as the reef continued to grow to the surface. Underwater volcanic ...
Scientists Say: Hypothesis
Hypothesis (noun, "Hi-PAH-theh-sis") This is an idea that may explain phenomena in the natural world. Making a hypothesis is one part of the process scientists use to make new discoveries. Before making a hypothesis, scientists may read about a topic to understand it better. They may talk with other scientists about it.
1.2: The Process of Science
Like geology, physics, and chemistry, biology is a science that gathers knowledge about the natural world. Specifically, biology is the study of life. The discoveries of biology are made by a community of researchers who work individually and together using agreed-on methods. In this sense, biology, like all sciences is a social enterprise like ...
Examining The Ways Science Studies The Natural World
The Goal of Science is Knowledge and Understanding. The primary goal of science is to acquire knowledge and understanding of the natural world. Scientists are driven by curiosity and a desire to uncover the underlying principles that govern the universe. Through systematic observation, experimentation, and analysis, they strive to increase our ...
1.2 The Scientific Methods
Scientists may test the hypothesis by performing an experiment. During an experiment, the scientist collects data that will help them learn about the phenomenon they are studying. Then the scientists analyze the results of the experiment (that is, the data), often using statistical, mathematical, and/or graphical methods.
3.1: Explaining the Natural World
3.1.2 Bacon: Observation and Induction. Francis Bacon (1561-1626) was an Englishman with many intellectual passions: law; politics; literature; history; and philosophy, including topics related to acquiring knowledge of the natural world.Among his other viewpoints that were revolutionary for his times, Bacon took exception to the prevailing Aristotelean preference for deduction over induction ...
Chapter 2 ~ Science as a Way of Understanding the Natural World
Thomas Kuhn (1922-1995) was a philosopher of science who emphasized the important role of "scientific revolutions" in achieving great advances in our understanding of the natural world. In essence, Kuhn (1996) said that a scientific revolution occurs when a well-established theory is rigorously tested and then collapses under the ...
How Science Makes Sense of the Natural & Designed World
The scientific method is the process scientists use to understand the natural world and how it works. In a nutshell, the goal is to find a way to get around the fact that our brains are terrible ...
Honors Bio Chapter 1 Assessment Flashcards
How does a hypothesis help scientists understand the natural world? it provides an answer to unsolved questions and then purposes further questions about the natural world that lead to new discoveries. Distinguish between an experimental group and a control group.
How does a hypothesis help scientist understand the natural world
A hypothesis is a possible explanation for an observable occurrence that is formed from limited knowledge. It can serve as a starting point for an investigation, or it may develop during an investigation. Hypotheses are works in progress and can change as new evidence and information are collected.
How does a hypothesis help scientists understand the natural world?
A hypothesis is based on observations that a scientist has made. The main way a hypothesis can help is by letting scientists reach a logical conclusion and explanation using a methodical approach. Whether a hypothesis is proved correct or incorrect, it is still new knowledge that has been gained.
How does a hypothesis help scientists understand the natural world
A hypothesis provides a focused and verifiable explanation for a particular phenomenon, helping scientists in their quest to understand the natural world.. It guides research activities and enables scientists to plan tests and gather data to assess the accuracy of hypotheses.Scientists advance our understanding of a subject by learning new things, discovering things, and testing hypothesis.
Biology- Chapter 1 Flashcards
A hypothesis helps scientists understand the natural world by suggesting a testable explanation for a set of observations Describe three possible ways in which a hypothesis may arise. Use of prior knowledge, logical inference, imaginative guess.
The beginnings of modern science shaped how philosophers saw alien life
Disclosure statement. Philip C. Almond does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no ...
how does a hypothesis help scientist understand the natural world
A hypothesis helps scientists understand the natural world by providing a framework for designing experiments, making observations, and analyzing data. It guides the scientific inquiry process and allows scientists to test their ideas and theories. By testing hypotheses, scientists can gather evidence to support or refute their proposed ...
Chapter 2 ~ Science as a Way of Understanding the Natural World
Thomas Kuhn (1922-1995) was a philosopher of science who emphasized the important role of "scientific revolutions" in achieving great advances in our understanding of the natural world. In essence, Kuhn (1996) said that a scientific revolution occurs when a well-established theory is rigorously tested and then collapses under the ...

1.2: Science as a Way of Understanding the Natural World

The Nature of Science

The Scientific Method

Facts, Hypotheses, and Experiments

Principles of Scientific Inquiry

Conclusions

Questions for Review

Questions for Discussion

Exploring Issues

References Cited and Further Reading

2: Science as a Way of Understanding the Natural World

The Nature of Science

Inductive and Deductive Logic

Goals of Science

Facts, Hypotheses, and Experiments

Uncertainty

Predictability

Variability

Accuracy and Precision

A Need for Scepticism

Conclusions

Questions for Review

Questions for Discussion

Exploring Issues

References Cited and Further Reading

A Guide to Using the Scientific Method in Everyday Life

Leave a Reply Cancel reply

Biology library

Introduction

Scientific method example: Failure to toast

2. Ask a question.

3. Propose a hypothesis.

4. Make predictions.

5. Test the predictions.

Logical possibility

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Hypothesis (noun, “Hi-PAH-theh-sis”)

In a sentence

1.2: The Process of Science

The Nature of Science

Natural Sciences

Scientific Inquiry

Hypothesis Testing

Basic and Applied Science

Reporting Scientific Work

Contributors and Attributions

Examining The Ways Science Studies The Natural World

Defining Science

Science Seeks Naturalistic Explanations

The Goal of Science is Knowledge and Understanding

Science is a Process, Not Just Facts

The Scientific Method

Making Observations

Forming a Hypothesis

Designing Experiments

Analyzing Results and Drawing Conclusions

Branches of Science

Physical Sciences (Physics, Chemistry, etc.)

Earth and Space Sciences

Life Sciences (Biology, Ecology, etc.)

Social Sciences

Tools and Technology in Science

Scientific Instruments

Laboratory Methods and Equipment

Field Research Methods

Computing and Data Analysis

Scientific Institutions and Communities

Scientific Societies and Organizations

Science Communication and Publishing

Funding and Policy

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