Introduction to the “Scientific Method” and Report Writing.
Objectives
1) To become familiar with the process of science, i.e. how scientists examine the natural world.
2) To practice this method.
3) To learn how to effectively report your observations/analysis so that your “peers” can understand and replicate your work.
II. Introduction
“Science” is both information about the natural world and a method for developing that understanding. The process that scientists use to examine the natural world is basically a formalized, and often joint, version of “critical thinking”.
Different individuals formulate the “scientific method” in somewhat different ways but we can generalize it as a series of steps that include some variation on the following:
1) Make observations on a topic of interest.
2) Formulate a Question or Hypothesis regarding this information.
3) Submit the hypothesis to some test of its validity.
4) Evaluate the result of the test to accept or reject the hypothesis.
5) Report your conclusions.
6) Others are now enabled to try to replicate, or contradict, your result.
One graphical description of the process is provided in your text:
Now let us look at these steps in a little greater detail.
1) Observation:
Curiosity is one of the basic traits of all humans. We are always experiencing the world around us and trying to understand its whats, hows, and whys?.
Indeed, this characteristic may be one of the main factors in our success as a species. Thus it is natural for us to observe and become interested in diverse topics. Scientists simply try to harness this natural curiosity and apply it in a formal way to particular topics.
The observations made by an individual scientist are usually focused on a topic of special interest to him or her (often due to some personal and non-scientific factor). These observations may be direct, or more commonly in modern science indirect i.e. by examining the results of the studies of other scientists. In either case, the good scientist must be aware of the biases and errors that they or the other scientists may show in their observations and conclusions. That is, they must employ basic critical thinking skills and verify the validity of the initial “data” they are using to form their ideas about nature. One scientist, Carl Sagan, referred to this activity as his bull***t detection kit.
2) The Question or Hypothesis:
This step in the process should narrow the focus of the inquiry from a general interest to a more specific and presumably unclear aspect of the topic of interest.
Some scientists think of questions as a simple but independent aspect of science, and others as only a minor step in forming a hypothesis. Some say that all good science should be “hypothesis driven” and that simple questions only lead to “data gathering”. However, often one person’s hypothesis may seem only a question to another and indeed some “data gathering” has lead to important discoveries i.e. you cannot ask how? or why? until you know what things actually exist. So we will take the more inclusive approach and consider a question to be an important but often simple aspect of science. (These could be such things as; will an increased dosage lead to a more efficient cure without undue side effects, will a modification in the shape, or number, of the blades of a wind turbine provide more efficient energy generation etc.)
The generation of a hypothesis proceeds from inductive reasoning. That is it proceeds from multiple specific facts to a possible general principle that unites them all, or an explanation of the mechanism of a (series of) natural event(s) etc. In essence a hypothesis is the scientist’s initial, tentative explanation of some aspect of the natural world. The major advantage of a hypothesis is that it should be predictive i.e. if it is correct then certain things should follow from it and be seen in nature.
3) Testing Hypotheses:
Here a scientist will use deductive reasoning. This requires movement from the general i.e. the explanatory hypothesis, to the specific i.e. a particular outcome of the hypothesis. In general the hypothesis will be restated in an If…. then…. statement. This involves a Prediction, - if my hypothesis is true then I should observe “X” under these specific conditions.
We say that to be truly scientific all hypotheses must be falsifiable. Supporting data can never prove a hypothesis, since there may be other hypotheses that would be equally likely, which we have not yet thought of. So we tend to proceed in the Sherlock Holmes mode – when you have eliminated most possible alternatives, whatever remains must be the truth i.e. science moves by successive approximations to the truth.
There are several ways that a question can be analyzed or a hypothesis tested:
a) Gather more data – does the new information answer the question or is that information consistent with the hypothesis thus increasing our confidence or does it refute the hypothesis.
b) Devise an Experiment – ideally this should be designed to falsify the hypothesis. Such evidence could “rule out” the hypothesis, while supporting results increase confidence but do not “prove” the idea.
To be valid, ideally all factors involved in the situation should be “controlled” by the experimenter. This would allow him or her to change just one factor – the “independent variable” (the X in an “if X” then…statement) while monitoring changes in the “dependent variable” (the Y in the “if X then Y” statement).
In many physical or chemical experiments such control can be closely approximated. However, in some physical and many biological experiments, precise control of all environmental factors is not possible. In these cases a “control group” is employed. Here, a group of organisms which closely resemble the group under test is exposed to the same environmental factors and procedures as the test group, with the exception of the specific “independent variable”. In this way random environmental factors can be accounted for.
c) The “natural experiment” – for some hypotheses an experimenter controlled test is impractical, impossible or unethical. In such a case the researcher should formulate their “if..then” statement of the hypothesis in such a way as to provide for the possibility that such an event might occur in nature or that such data could be collected from observation of ongoing natural events. This event can be sought or a statistical analysis preformed on a population etc. to find supporting or negating evidence for the hypothesis.
4) Evaluate the results:
Scientists collect both qualitative and quantitative data. In some cases qualitative data can provide a discrete answer i.e. the predicted event did or did not occur providing a discrete yes or no, acceptance or rejection of the hypothesis. More often, however, the reliability of quantitative data is first analyzed by statistical tests and then evaluated as providing a degree of support (or not) for the hypothesis under test.
Generally simple questions lead to (somewhat) discrete answers and to other questions. A hypothesis may be accepted, rejected or modified. Most new hypotheses probably will need to be modified after their initial test. For example, the experiment may be seen as mostly consistent with the hypothesis under the bulk of the conditions tested but showing weakness under certain circumstances. In such a case the hypothesis would be adjudged to be inadequate and a modified version generated to account for the exceptions. This new hypothesis would then need to be tested. Doing science is a reiterative process.
5) Report the conclusions of the study:
The purpose of a scientific study is to add to the sum total of human understanding of the natural world. It is only after a result is disseminated to the public that any benefit can be gained from it. Science is not science until it is communicated. Information kept to oneself is useless (and unconfirmed). At the end of this exercise we will describe the standard means by which scientist communicate with one another and with the general public.
6) Confirmation or challenge of the result:
Science today is a joint project. Progress involves many individual scientists checking and rechecking their own and other’s work. When an individual researcher or group initially submits their study results to a journal, the editor will send their manuscript to a series of other scientists who work on similar topics (and indeed often a competitor) for their opinion as to whether the study was done correctly. Only after these “reviewers” are satisfied (often requiring re-writes or indeed additional experiments) will the paper be officially published.
Then the real critique starts. Now researchers from around the world can see your work and return to their labs to attempt to confirm or challenge, or even falsify your idea by creating alternate experimental tests. In this fashion errors of all sorts are (relatively) quickly weeded out.
In this way we gain increasing confidence in the validity of work that has withstood the “test of time” and repeated challenge by other scientists. Indeed some ideas take on a more concrete, or secure status as principles that are generally accepted in the particular field.
Ultimately, (and fairly rarely), a new Theory may evolve. A Scientific Theory may derive from one, or more than one, well tested hypotheses and itself will be subjected to additional tests of its new and integrative features. As such Scientific Theories are considered to be the best presently available explanation of a natural phenomenon.
III. The lab exercise
In today’s laboratory, your TA will present you with an observation related to the reaction some people have to eating spicy foods. As a class you should discuss this observation, and construct some hypotheses that could explain the observation. You will then design an experiment to test one of these hypotheses. One particularly important part of good scientific practice is keeping good written documentation, of both the thought processes, and data generated by experiments. This is critical for communication with scientific peers, and the general public, through the writing of journal articles, reports, theses, etc. Your memory is not as good as you might think!
Use the table below to document the preliminary steps used for today’s experiment.
OBSERVATIONQUESTION
HYPOTHESIS
In class discussion, determine what your experimental procedure will be to test the hypothesis proposed above. Remember that the combination of a well formulated hypothesis and its experimental test should allow you to make some predictions about what the results of the experiment will be. Think along the lines of “if the hypothesis was a viable explanation of the observation we made, and we perform this experiment, then we would expect to see these results”. An experiment may have only one prediction, or several, depending on the complexity of the hypothesis, and the experiment.
Now, use the space below to write a detailed description of the experimental procedure. Remember, for the scientific method to work, other scientists need to know the details of your procedure so they can recreate your experiment to determine if your results were correct, or not. Include what your test groups are, how you will administer the test treatments, what your controls are, how you will make any measurements involved, etc.
Experimental Procedure:
So, if you conduct this test, based on your hypothesis, what do you expect to find?
Predictions:
Experimentation and Data Collection:
Follow the directions your TA provides, and your documented experimental procedure to conduct your experiment. Take careful notes, and record all data carefully.
Evaluation of the hypothesis:
Now you can evaluate your experimental data. Does the data you collected support or contradict the prediction(s) you made? If the data support or contradict your prediction(s), what does it mean for your hypothesis?
IV. Questions
In comparing results of different groups does the type of control used appear to be an important factor?
What complications to the experiment might taking body temperature orally produce for this experiment?
Why is it important to take body temperature before, and after you ate salsa?
Experiments frequently reveal weaknesses in our experimental methods; did you find any weaknesses in this experiment that you could do differently in a next experiment that might help you more strongly support, or refute your hypothesis?
Did the results of this experiment make you think of any new questions?
Did your experimentation cause you to consider any other hypotheses that you could test?
V. Writing a Lab Report
The format of scientific papers and reports is designed to facilitate the way in which scientists communicate with each other. Here it is important to be precise and give sufficient detail so that readers can understand exactly why the study was carried out, and the method used to test the hypothesis. Hopefully, then, other investigators in the field could repeat the experiment, confirm the data and expand the field with new hypotheses followed by experiments.
Generally a formal scientific paper has 7 components:
Title: A concise, descriptive statement of the study
Abstract: A brief description of the question, how it was addressed, and some suggestion of the results obtained.
Introduction: A more general statement of the background data that generated the question, the hypothesis being tested and the rational for the experimental design.
Materials and Methods: A detailed description of what and how the study was done.
Results: A succinct presentation of the data obtained.
Discussion: The author’s reasoned interpretation of the “answer” to the question raised by the background data, in the light of these new results.
References: A listing of all previous publications that contributed to the ideas or methodology employed in the present study.
For our purposes in this course we will use a modified version of the “scientific paper” as the format for our lab reports. This will allow those of you who intend to continue in the general field to begin to hone your skills and provide an opportunity for all to become familiar with reading and writing technical material – a skill that will become more important in general life – e.g. instructions for electronic devices, processed food ingredients/preparation, medical reports etc. Here, we will combine the abstract and introduction into a “Background” statement.