1.3: The Process of Science

The Process 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”) is a process that uses evidence, logic, and creativity to discover and explain natural and physical phenomena while avoiding bias. The scientific method is a systematic approach to research, consisting of defined steps that include conducting experiments and making careful observations.

The steps of the scientific method will be examined in detail later, but one of its most important aspects is testing hypotheses through repeatable experiments. A hypothesis is a proposed explanation for an event that can be tested. Although using the scientific method is inherent to science, it is inadequate in determining what science is. A hypothesis can evolve into a theory over time as evidence accumulates. A theory is a well-tested and confirmed explanation for observations or phenomena. Science may be better defined as fields of study that seek to understand the physical and natural underpinnings of the universe.

What is Science?

National Resources Defense Council scientists share how their discipline works, what they love about it, and the wonder about our world it provides. (2 min)

Nature is Understandable

Scientists view nature as a unified system governed by natural laws. By discovering natural laws, scientists strive to increase their understanding of the natural world. Laws of nature are expressed as scientific laws. A scientific law is a statement that describes what always happens under certain conditions in nature.

Scientific Ideas are Open to Change

Science is more of a process than a set body of knowledge. Scientists continually test and revise their ideas, and as new observations are made, existing ideas may be challenged. Ideas may be replaced with new ideas that better fit the facts, but more often existing ideas are simply revised. For example, when scientists discovered how genes control genetic traits, they didn't throw out Mendel's laws of inheritance. The new discoveries helped to explain why Mendel's laws applied to certain traits but not others. They showed that Mendel's laws are part of a bigger picture. Through numerous new discoveries over time, scientists have gradually built an increasingly accurate and detailed understanding of the natural world.

Occasionally, scientific ideas change radically. Radical changes in scientific ideas were termed paradigm shifts by the philosopher Thomas Kuhn in 1962. Kuhn agreed that scientific knowledge typically accumulates gradually, as new details are added to established theories. However, Kuhn also argued that from time to time, a scientific revolution occurs in which current theories are abandoned, and completely new ideas take their place.

Although there is debate among scientists over what constitutes a paradigm shift, the theory of evolution is widely accepted as a prime example in biology. In fact, some scientists argue that it is the only example of a paradigm shift in biology. Prior to Charles Darwin's publication of his theory of evolution in the 1860s, most scientists believed that a god had created living species and that species on Earth had not changed since their creation. Drawing on a wealth of evidence and logical arguments, Darwin demonstrated that species can change and that new species can arise from pre-existing ones. This was such a radical shift in scientific thinking that Darwin was reluctant to publish his ideas, fearing a backlash from other scientists and the public. Indeed, Darwin was initially ridiculed for his theory of evolution, but over time, it gained widespread acceptance and became a cornerstone of the life sciences.

Scientific Knowledge May Be Long Lasting

Many scientific ideas have withstood the test of time. For example, about 200 years ago, John Dalton proposed the atomic theory: that all matter is made of tiny particles called atoms. This theory is still valid today. Over the past two centuries, a great deal more has been learned about atoms and the even smaller particles that comprise them. Nonetheless, the idea that all matter consists of atoms remains valid. There are numerous other examples of fundamental scientific ideas that have been repeatedly tested and found to be sound. You will learn about many of them as you study the biology of women.

Brief History of Natural Science

Although modern biology is a relatively recent development, sciences related to and included within it have been studied since ancient times. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, Egypt, the Indian subcontinent, and China. However, the origins of modern biology and its approach to studying nature are most often traced back to ancient Greece. In fact, "biology" is derived from the Greek word "bio" meaning "life" and the suffix "ology" meaning "study of.")

The scientific method was used in ancient times, but it was first formally documented by England’s Sir Francis Bacon (1561–1626), who established the first systematic methodology for scientific inquiry. The scientific method is not used exclusively by biologists; it can be applied to almost all fields of study as a logical, rational problem-solving approach. Observations in natural history and advances in microscopy have also had a profound impact on biological thinking.

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, environmental science, computer science, geology, logic, physics, chemistry, and mathematics. However, those fields of science related to the physical world and its phenomena and processes are considered natural sciences. Thus, a natural sciences museum might contain any of the items listed above.

However, there is no complete agreement on what constitutes the natural sciences. For some experts, the natural sciences are astronomy, biology, chemistry, earth science, and physics. Other scholars divide the natural sciences into life sciences, which study living things and include biology, and physical sciences, which study nonliving matter and include astronomy, geology, physics, and chemistry. Some disciplines, such as environmental science, biophysics, and biochemistry, draw on both life and physical sciences, making them interdisciplinary.

The natural sciences often rely on quantitative (numerical) data, although some may also use qualitative (non-numerical) data to support their findings.

Not surprisingly, the natural science of environmental science has many branches or subdisciplines. Environmental toxicologists study the impacts of various compounds on humans and the environment, while climate scientists investigate patterns in temperature and rainfall across large areas and over long periods. Even within a particular field, there is specialization; hydrologists may study surface water and/or groundwater patterns, engage in flood mitigation, or assist with water-use planning. Some areas of environmental science focus on studying non-living aspects of the environment, while others investigate the impacts of the environment on living organisms.

What Really Happens to the Plastic You Throw Away

An example of the complexity of understanding the environmental implications of using something as simple as a plastic water bottle. (~4 min)
Question after watching: How many different areas of research can you identify in the video that could be used to find solutions to the problem of single-use plastics?

Scientific Reasoning

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 strive to comprehend the world and its workings. To do this, they use two methods of logical thinking: inductive reasoning and deductive reasoning (Figure \(\PageIndex{1}\)).

• 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 or quantitative, and the raw data can be supplemented with drawings, pictures, photos, or videos. From numerous observations, scientists can infer conclusions (inductions) based on the evidence. Inductive reasoning involves formulating generalizations from careful observation and analysis of large amounts of data. Brain studies provide an example. In this type of research, many participants' brains are observed while they perform a specific activity, such as viewing images of food. The part of the brain that “lights up” during this activity is then predicted to be the part controlling the response to the selected stimulus, in this case, images of food. Then, researchers can stimulate that part of the brain to see if similar responses result.
• 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 compared to inductive reasoning. It is a form of logical thinking that uses a general principle or law to forecast specific results. From these general principles, a scientist can extrapolate and predict specific results that remain valid as long as the principles themselves remain valid. Studies in climate change can illustrate this type of reasoning. For example, scientists may predict that if the climate in a particular region warms, the distribution of plants and animals should change. These predictions have been made and tested, and numerous such changes have been identified, including modifications to arable areas for agricultural purposes, with adjustments based on average temperatures.

Inductive and deductive reasoning are often used in tandem to advance scientific knowledge.

Figure \(\PageIndex{1}\): Inductive vs Deductive Reasoning

Video

Many students confuse deductive reasoning with inductive reasoning, and vice versa. Learn the difference! (~3 min)
Question after watching: Reflect on incidents/events in your life where you applied deductive and inductive reasoning. Describe them and why they are instances of inductive and deductive reasoning.

Optional Activity \(\PageIndex{1}\)

Decide if each of the following is an example of inductive or deductive reasoning.

1. All flying birds and insects have wings. Birds and insects flap their wings as they move through the air. Therefore, wings enable flight.
2. Insects generally survive mild winters better than harsh ones. Therefore, insect pests will become increasingly problematic if global temperatures continue to rise.
3. Chromosomes, the carriers of DNA, separate into daughter cells during cell division. Therefore, DNA is the genetic material.
4. Animals as diverse as humans, insects, and wolves all exhibit social behavior. Therefore, social behavior must have an evolutionary advantage.

Answer

1: inductive; 2: deductive; 3: deductive; 4: inductive.

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, which is usually inductive, aims to observe, explore, and discover.
• Hypothesis-based science, which is usually deductive, begins with a specific question or problem and a potential answer or solution that can be tested. In hypothesis-based science, specific results are predicted from a general premise.

The boundary between descriptive science and hypothesis-based science is often blurred, and most science incorporates elements of both. This becomes apparent when thinking about how easily observation can lead to specific questions. For example, a gentleman in the 1940s observed that burrs stuck to his clothes and his dog’s fur had tiny hooked structures. He discovered that these burrs gripped more reliably than a zipper. He invented the hook-and-loop fastener, now known as Velcro, and founded a company. Descriptive science and hypothesis-based science were used together here to make discoveries and answer questions.

Video

Explore how medical scientists work to answer scientific questions and the complications in building studies that involve humans. (~5 min)
Questions after watching: What are the important things to consider for these scientists?

Science and Culture

From the United Nations Educational, Scientific and Cultural Organization (UNESCO):

"Science is the greatest collective endeavor. It contributes to ensuring a longer and healthier life, monitors our health, provides medicine to cure our diseases, alleviates aches and pains, helps us to provide water for our basic needs – including our food, provides energy and makes life more fun, including sports, music, entertainment and the latest communication technology. Last but not least, it nourishes our spirit.

Science generates solutions for everyday life and helps us to answer the great mysteries of the universe. In other words, science is one of the most important channels of knowledge. It has a specific role, as well as a variety of functions for the benefit of our society: creating new knowledge, improving education, and increasing the quality of our lives.

Science must respond to societal needs and global challenges. Public understanding and engagement with science, and citizen participation including through the popularization of science are essential to equip citizens to make informed personal and professional choices. Governments need to make decisions based on quality scientific information on issues such as health and agriculture, and parliaments need to legislate on societal issues which necessitate the latest scientific knowledge. National governments need to understand the science behind major global challenges such as climate change, ocean health, biodiversity loss and freshwater security.

To face sustainable development challenges, governments and citizens alike must understand the language of science and must become scientifically literate. On the other hand, scientists must understand the problems policy-makers face and endeavor to make the results of their research relevant and comprehensible to society.

Challenges today cut across the traditional boundaries of disciplines and stretch across the lifecycle of innovation -- from research to knowledge development and its application. Science, technology and innovation must drive our pursuit of more equitable and sustainable development" (2021).

Conducting Science

Biologists study the living world by posing questions about it and seeking science-based responses. This approach is also common in other sciences and is often referred to as the scientific method. The scientific process typically starts with an observation (often a problem to be solved) that leads to a question. 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 observation also describes a problem: the classroom is too warm. The student then asks, “Why is the classroom so warm?” This is a testable question.

Video

Learn about the 5 criteria that a testable question should meet in this 7.5-minute video.

Optional Activity \(\PageIndex{2}\)

Read the following questions (Q) and their associated hypothesis (H). Does the statement lend itself to investigation using the scientific method? In other words, is the hypothesis falsifiable (can be proven false)?

1. (Q) Is macaroni and cheese tastier than broccoli soup? (H) Macaroni and cheese is not tastier than broccoli soup.
2. (Q) Are hummingbirds attracted to the color red? (H) Hummingbirds are not attracted to the color red.
3. (Q) Is the moon made out of green cheese? (H) The moon is made of green cheese.
4. (Q) Is plagiarism dishonest? (H) Plagiarism is not dishonest.

1. Hypotheses 1 and 2 are subjective and cannot be tested using the scientific method. Hypotheses 3 and 4 can be tested using the scientific method.
2. Hypotheses 3 and 4 are subjective and cannot be tested using the scientific method. Hypotheses 1 and 2 can be tested using the scientific method.
3. Hypotheses 1 and 3 are subjective and cannot be tested using the scientific method. Hypotheses 2 and 4 can be tested using the scientific method.
4. Hypotheses 1 and 4 are subjective and cannot be tested using the scientific method. Hypotheses 2 and 3 can be tested using the scientific method.

Answer

d.  Hypotheses 1 and 4 are subjective and cannot be tested using the scientific method. Hypotheses 2 and 3 can be tested using the scientific method.

Proposing a Hypothesis

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, the student can make a prediction. 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.”

Video

In this 7-minute video, learn the difference between a fact, a theory, a hypothesis, and a scientific law.
Question BEFORE and AFTER watching: How would you define hypothesis and theory?

Testing a Hypothesis

A valid hypothesis must be testable. It should also be falsifiable, meaning that it can be disproven by experimental results. Importantly, science does not claim to “prove” anything because scientific understanding is always subject to modification in light of further information. This step—openness to disproving ideas—is what distinguishes sciences from non-sciences. The presence of the supernatural, for instance, is neither testable nor falsifiable. To test a hypothesis, a researcher will conduct one or more experiments designed to eliminate one or more of the hypotheses.

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.
• The control group contains all the same conditions as the experimental group, EXCEPT for the variable being tested.
• If the results of the experimental group differ from those of the control group, the difference must be due to the manipulation, rather than to some outside factor.
• Identify the variables and controls in the examples from the section above.

Revisit the hypotheses from the section above:

1. The classroom is warm because no one turned on the air conditioning.
2. The classroom is warm because there is a power failure, and so the air conditioning doesn’t work.

To test the first hypothesis, the student would determine whether the air conditioning is on. If the air conditioning is turned on but does not work, there should be another reason, and this hypothesis should be rejected. To test the second hypothesis, they could check if the classroom lights are functional. If so, there is no power failure, and this hypothesis should be rejected. Each hypothesis should be tested by carrying out appropriate experiments. 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 \(\PageIndex{3}\)). Using the scientific method, hypotheses inconsistent with experimental data are rejected.

While this “warm classroom” example is based on observational results, other hypotheses and experiments might have clearer controls. For instance, a student might attend class on Monday and realize they had difficulty concentrating on the lecture. One observation that might explain this occurrence is, “When I eat breakfast before class, I am better able to pay attention.” The student could then design an experiment with a control to test this hypothesis, including keeping all details of their morning the same but eating breakfast one day versus another to see how their attention holds in class.

Drawing Conclusions

If the evidence of an experiment indicates that the hypothesis is supported, does this mean that the hypothesis is true? No, not necessarily. That's because a hypothesis can never be proven conclusively to be true. Scientists can never examine all possible evidence, and someday evidence may be found that disproves the hypothesis. In addition, other hypotheses, as yet unformed, may be supported by the same evidence. For example, something else introduced unknowingly into the experiment might be responsible for the outcome. Although a hypothesis cannot be proven true without a shadow of a doubt, the more evidence that supports a hypothesis, the more likely the hypothesis is to be correct. Similarly, the better the match between actual and expected observations, the more likely a hypothesis is true.

Many times, competing hypotheses are supported by evidence. When that occurs, how do scientists conclude which hypothesis is better? Several criteria can be used to evaluate competing hypotheses. For example, scientists are more likely to accept a hypothesis that:

• explains a wider variety of observations.
• explains observations that were previously unexplained.
• generates more expectations and is thus more testable.
• is more consistent with well-established theories.
• is more parsimonious, that is, it is a simpler and less convoluted explanation.

Communicating Results

The last step in a scientific investigation is communicating the results to other scientists. This is a crucial step because it enables other scientists to attempt to replicate the investigation and verify if they can obtain the same results. If other researchers get the same results, it adds support to the hypothesis. If they get different results, it may disprove the hypothesis. When scientists communicate their results, they should clearly describe their methods and highlight any potential issues or limitations with the investigation. This allows other researchers to identify any flaws in the method or consider ways to avoid potential problems in future studies.

Repeating a scientific investigation and reproducing the same results is called replication. It is a cornerstone of scientific research. Replication is not required for every scientific investigation, but it is highly recommended for those that yield surprising or particularly consequential results. In some scientific fields, scientists routinely attempt to replicate their own investigations to ensure the reproducibility of their results before communicating them.

Scientists can communicate their results in various ways. The most rigorous approach is to write up the investigation and results as an article and submit it to a peer-reviewed scientific journal for publication. The journal's editor provides copies of the article to several other scientists working in the same field. These are the peers in the peer-review process. The reviewers study the article and inform the editor whether they believe it should be published, based on the validity of the methods and the significance of the study. The article may be rejected outright or accepted, either as is or with revisions. Only articles that meet high scientific standards are ultimately published.

Optional Activity \(\PageIndex{3}\)

In the example above, the scientific method is employed to solve a common everyday problem. Order the scientific method steps (numbered items) with the process of solving the everyday problem (lettered items). Based on the experiment's results, is the hypothesis correct? If it is incorrect, propose some alternative hypotheses.

1. Observation
2. Question
3. Hypothesis (answer)
4. Prediction
5. Experiment
6. Result

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

Answer

1: C; 2: F; 3: A; 4: B; 5: D; 6: E. The original hypothesis is incorrect, as the coffeemaker works when plugged into the outlet. Alternative hypotheses include that the toaster is broken or that it wasn't turned on.

Basic and Applied 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 aims to use science to solve real-world problems, such as improving crop yield, finding a cure for a particular disease, or saving 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 it is time to move on from basic science and instead focus on solving real problems. Both approaches are valid. It is true that there are problems that demand immediate attention; however, few solutions would be found without the knowledge generated by 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 to each person, 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 (through basic science) 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 (all examples of applied science). 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 the DNA code 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 better understand human chromosomes. The Human Genome Project relied on basic research conducted with non-human organisms and, later, on the human genome. An important end goal eventually became the use of the data for applied research aimed at developing cures for genetic diseases.

Feature: Science in the News

Scientific research is often reported in the popular media, and that is how most people learn about new scientific findings. Informing the public about scientific research is a valuable media service, but the types of scientific investigations that are reported may lead to a distorted public perception of what science is and how reliable its results are. Why? There are actually two types of science, often referred to as consensus science and frontier science. The latter type of science is usually the one that makes the news, but the media generally do not distinguish between the two. Therefore, many people may infer that what they read about frontier science is typical of all science.

• Consensus science refers to scientific ideas that have been researched for a long period of time and for which a great deal of evidence has accumulated. This type of research typically aligns well with current scientific paradigms. A notable example of consensus science is global climate change. Data showing the impact of increasing levels of atmospheric carbon dioxide, due to human activities, on global warming have been accumulating for many decades. Today, virtually all climate scientists agree that global warming is occurring and that human actions are largely responsible for it. However, the few scientists — and many politicians — who disagree with the consensus view receive greater media attention because the consensus view is considered "old" news. The findings have been accumulating for years, and new research in the area continues to yield similar results.
• Frontier science, in contrast, refers to scientific ideas that are relatively new and have not yet been supported by years of scientific evidence. Frontier research occurs at the forefront of knowledge in a specific field. A good example of frontier science is research into the presumed link between dietary cholesterol and blood cholesterol levels. The consensus view for many years was that a diet high in cholesterol increases blood levels of cholesterol, which may lead, in turn, to cardiovascular disease. Recent research challenging the accepted view found that genes play a greater role than diet in determining blood cholesterol levels and the risk of cardiovascular disease.

The media tend to focus on frontier science because it is exciting, may seem controversial, and could lead to major new scientific breakthroughs. With more research, ideas in frontier science may be supported by more evidence, gain wider acceptance, and become consensus science. In some cases, frontier science that contradicts a current paradigm may even lead to a paradigm shift.

However, the opposite may happen instead. Additional research may undermine the initial findings of frontier research, leading to the rejection of new and exciting ideas. Unfortunately, when frontier science is later shown to be mistaken, people may infer that all science, including consensus science, is unreliable.

Not All Current Questions Can be Answered by Science

Science rests on evidence and logic, and evidence comes from observations. Therefore, science deals only with things that can be observed. An observation is anything that is detected through human senses or with instruments and measuring devices that extend human senses. Things that cannot be observed or measured by current means or technology — such as supernatural beings or events — are outside the bounds of science. Consider these two questions about life on Earth:

• Did life on Earth evolve over time?
• Was life on Earth created by a supernatural deity?

The first question can be answered by science based on scientific evidence, such as fossils, molecular clocks, geological evidence, and more.

The second question could be a matter of belief, but no evidence can be gathered to support or refute it. Therefore, it is outside the realm of science.