Lab #1: An Introduction to the Scientific Method
Objectives:
1. To learn how scientists seek to improve our understanding of natural
phenomena.
2.
To put the scientific method into practice.
I. INTRODUCTION
Today’s scientists use a logical series of steps in their research known as the
Scientific Method. There are six interrelated steps as shown in the diagram
below.
Successful experimental design relies on a good, testable hypothesis. Our
hypothesis should be phrased in the “If . . . Then . . . “ language, and allow us
to test if certain variables are responsible for the observations we made.
The hypothesis will act as our prediction and potential explanation for the
phenomena we observe. Keep initial hypotheses simple and address each
problem systematically.
Experiments should be designed and clearly documented so that other
scientists will be able to perform the exact same procedure to validate your
results. The experimental methods should include both variables and
controls. Variables will be the parts of the experiment that we
systematically change to test our hypothesis. Controls are the parts of the
experiment that will remain unchanged, so we have a reference point to
compare our experimental variables.
As we perform the experiment, the data will be collected and then shared
and analyzed as a group. Evaluating the data and comparing it to our original
predictions is a critical moment in the Scientific Method. This step allows us
to determine if our predictions were correct, or if we need to change our
predictions or our experimental methods.
One of the goals of using the scientific method is to generate data that will
help us determine if we can accept or reject our hypothesis. Proving that the
hypothesis is true, however, is not our intent. Scientific conclusions will
remain tentative, leaving open the opportunity for other researchers to
reproduce the same data or address the hypothesis with different methods.
The Scientific Method is a continuous process, and the conclusions from one
experiment will often lead to new observations and additional hypotheses.
II. Using the Scientific Method
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 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.
OBSERVATION
QUESTION
HYPOTHESIS
In class discussion, determine what your experimental procedure will be to
test the hypothesis proposed above. 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:
Ok, now that you know how you will test your hypothesis, you should be able
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.
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?
III. Questions
1. Why did you use mild salsa as a control instead of eating no food at
all?
2. What complications to the experiment might taking body temperature
orally produce for this experiment?
3. Why is it important to take body temperature before, and after you
ate salsa?
4. 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?
5. Did the results of this experiment make you think of any new
questions?
6. Did your experimentation cause you to consider any other hypotheses
that you could test?