Earth image Scientific Method and the Nature of Science

Dr. Pamela Gore
Georgia Perimeter College

Objectives

  1. Describe the steps involved in the Scientific Method.
  2. Explain the difference between the scientist's use of the word "theory", and the use of the word in casual conversation.
  3. Explain what is meant by the method of multiple working hypotheses.
  4. Explain how Occam's Razor is used.
This section addresses, in whole or in part, the following Georgia GPS standard(s):
  • S6CS1. Students will explore the importance of curiosity, honesty, openness, and skepticism in science and will exhibit these traits in their own effort to understand how the world works.
  • S6CS1a. Understand the importance of - and keep - honest, clear and accurate records in science.
  • S6CS1b. Understand that hypotheses are valuable if they lead to fruitful investigations, even if the hypotheses turn out not to be completely accurate descriptions.
  • S6CS7b. Recognize that there may be more than one way to interpret a given set of findings.
  • S6CS8c. As prevailing theories are challenged by new informaiton, scientific knowledge may change and grow.
  • S6CS9. Students will investigate the features of the process of scientific inquiry.
  • S6CS9a. Scientific investigations are conducted for different reasons. They usualy involve collecting evidence, reasoning, devising hypotheses, and formulating explanations.
  • S6CS9c. Accurate record keeping, data sharing, and replication of results are essential for maintaining an investigator's credibility with other scientists and society.

This section addresses, in whole or in part, the following Benchmarks for Scientific Literacy:
  • Scientific knowledge is subject to modification as new information challenges prevailing theories and as a new theory leads to looking at old observations in a new way.
  • When similar investigations give different results, the scientific challenge is to judge whether the differences are trivial or significant, and it often takes further studies to decide. Even with similar results, scientists may wait until an investigation has been repeated many times before accepting the results as correct.
  • Scientists differ greatly in what phenomena they study and how they go about their work. Although there is no fixed set of steps that all scientists follow, scientific investigations usually involve the collection of relevant evidence, the use of logical reasoning, and the application of imagination in devising hypotheses and explanations to make sense of the collected evidence.
  • Accurate record-keeping, openness, and replication are essential for maintaining an investigator's credibility with other scientists and society.
  • New ideas in science sometimes spring from unexpected findings, and they usually lead to new investigations.
  • Clear communication is an essential part of doing science. It enables scientists to inform others about their work, expose their ideas to criticism by other scientists, and stay informed about scientific discoveries around the world.

This section addresses, in whole or in part, the following National Science Education Standards:
  • Different kinds of questions suggest different kinds of scientific investigations. Some investigations involve observing and describing objects, organisms, or events; some involve collecting specimens; some involve experiments; some involve seeking more information; some involve discovery of new objects and phenomena; and some involve making models.
  • Current scientific knowledge and understanding guide scientific investigations. Different scientific domains employ different methods, core theories, and standards to advance scientific knowledge and understanding.
  • Scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories. The scientific community accepts and uses such explanations until displaced by better scientific ones. When such displacement occurs, science advances.
  • Science advances through legitimate skepticism. Asking questions and querying other scientists' explanations is part of scientific inquiry. Scientists evaluate the explanations proposed by other scientists by examining evidence, comparing evidence, identifying faulty reasoning, pointing out statements that go beyond the evidence, and suggesting alternative explanations for the same observations.
  • Scientific investigations sometimes result in new ideas and phenomena for study, generate new methods or procedures for an investigation, or develop new technologies to improve the collection of data. All of these results can lead to new investigations.

Scientific Method

Science operates through the use of the Scientific Method. This is a method of study in which scientists work like detectives to gather data, and to figure out what happened. First, the scientific investigation begins with a question or an observation which leads to a question. Examples of such questions are:

The data needed to answer the question may be obtained through observations and/or experiments, which can be repeated and verified by others. Typically, a number of ideas or interpretations are developed to explain what happened. Each idea or interpretation is called a hypothesis. When scientists come up with several possible explanations, that is called the "method of multiple working hypotheses".

Each hypothesis is tested by experimenting or by making additional observations of various types to see if the observations support the hypothesis or not. The hypothesis could either be:

  1. accepted (meaning that it appears to be the correct explanation)
  2. rejected (meaning that it does NOT appear to be a correct explanation of the data), or
  3. modified (meaning that the explanation is changed so that it better explains the data).

Generally, when evaluating several hypotheses which all appear to be equally plausible, the simplest (or most parsimonious) explanation is the one selected to explain the observations. This technique of evaluating hypotheses is called Occam's razor or the Principle of Parsimony.

With the Scientific Method, there can be no discussion of "belief" or the "supernatural". There is no preconceived "right" answer that scientists are trying to justify. Scientists look for an explanation that is consistent with the observations and with the physical and chemical laws governing the Universe.

In some cases, when one hypothesis is accepted and others are rejected, it becomes a theory. A theory is a hypothesis with considerable experimental or observational support, generally with peer review or input from other scientists. Theories must also be able to make testable predictions. Scientists present their preliminary finding at professional meetings before other scientists who ask probing questions, and sometimes set out to repeat the observations and experiments, or to test the predictions of the theory. In geology, this sometimes takes the form of field trips where other scientists examine the rock outcrops and fossils to repeat the initial observations. Scientists must ultimately publish their research in a professional journal, which is distributed widely to other scientists who also may repeat the observations and experiments, and who sometimes publish rebuttals or criticisms of the original work. Ultimately, if a hypothesis appears to stand up to repeated scrutiny, it may be labeled a theory. Note that theories can never be proven, but theories can be disproved if there appears to be observational or experimental data that contradict the theory, or if the predictions of the theory are incorrect.

Please note that the scientific use of the word "theory" is VERY different from a non-scientist's use of the word. People often say "I have a theory as to why that happened," or "my Grandma has a theory as to why it is raining so much this year", or "my theory is that so-and-so committed the crime". This is an incorrect usage of the word theory because the idea has not been tested and verified. A better word for people to use in casual conversation would be "hypothesis". The misuse of the word "theory" by the general public has led to a misunderstanding of exactly what is meant when a scientist uses the word "theory", and in turn, a misunderstanding of the nature of science itself.

Summary of the Scientific Method

  1. A question arises.
  2. Observations (collect data)
  3. Develop multiple working hypotheses (ideas to explain the observations)
  4. Test the hypotheses by experimenting and either
    1. a. accept
    2. b. reject, or
    3. c. modify the hypothesis
  5. The simplest explanation is best.
  6. When a hypothesis has considerable experimental or observational support, it is accepted and others are rejected, and it may become a theory.

Why do scientists do science?
In many cases, they are collecting information on something that has not been studied before in order to satisfy intellectual curiosity. Scientists may want to discover something new that changes how we think about something in nature. Perhaps they are hoping to discover a new type of bacteria, a new species of plant or insect, a new subatomic particle, a new phenomenon, or a previously undiscovered type of fossil. Sometimes scientists are trying to test new ideas or to disprove old ones. Perhaps a discovery will explain something not previously explained. Or perhaps a discovery will overturn a previously accepted idea. New ideas in science sometimes spring from unexpected findings, and they usually lead to new investigations.

It is important to keep accurate records of scientific observations or experiments (such as in a bound notebook, that pages cannot be removed from, or inserted into). The records must not be "copied over" from the actual data recorded at the time of the observation (a mistake we commonly see in science fair projects). Messy original records are much more preferable to something that has been transcribed (and possibly changed). In addition, one should not erase records of scientific observations. If necessary draw a line through the original statement, and rewrite it. Observations must be verifiable or reproducible. Data must never be fudged or made up or faked. Records must be open and shared. Replication is essential for maintaining an investigator's credibility with other scientists and society.

In order to gain acceptance by the scientific community, a theory must be based on observation of natural phenomena and/or experimentation that tries to simulate natural processes under controlled conditions, and it must be able to make testable predictions. New ideas and new theories must be verifiable.

Note that although the consequences of a theory can be verified, a theory can not be "proved", but only disproved. At some point, limitations of a theory may be discovered, and a theory may be need to be modified.

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Page created by Pamela J.W. Gore
Georgia Perimeter College,
Clarkston, GA

Page created March 11, 2005
Modified April 26, 2005
Updated May 16, 2008