The SCIENTIFIC
METHOD is the logical way in which a scientist goes about trying to solve a
problem. A student needs to understand the scientific method, and the words
that are used to describe the process. The actual descriptions of the steps of the
scientific method will vary from text to text, but the underlying process remains the
same. The steps of the scientific method are shown below:
1. State the problem.
2. Collect observations.
3. Form a hypothesis.
4. Test the hypothesis.
5. Form a theory.
6. Modify a theory.
Now, let us review a real life example of
how you might use the scientific method. Suppose you notice an area in your front
lawn where the grass is not growing correctly. The rest of your lawn has thick,
green grass, but this one area has very sparse grass. This, then, is your problem.
1. State the problem.
"Grass won't grow in that area of my lawn!"
You would then go outside and look
at that area. What makes that area different from the areas where the lawn is
growing nicely? Does one area get more or less sun? What is the soil like?
Compare as many likely factors that you can think of.
2. Collect
observations. "The sparse area is surrounded by several evergreen
trees, which drop needles and block much of the sunlight. The soil appears just as
rich as the soil in other areas, but the pH is lower. All areas seem to be getting
similar amounts of water. The temperature in the shaded area is lower than the areas
that are not shaded."
Based on the information that you gathered, and your knowledge of
Biology, you are ready to form a hypothesis. Remember, a hypothesis is an educated
guess. It is only your background knowledge in this subject that separates a true
hypothesis from what would merely be a guess. Now, considering the observations you
made, you might decide that pH of the soil in the sparse area is the problem. You
form a hypothesis and put it in what is called "if . . . then" format.
3. Form a hypothesis.
"If the pH of the soil was higher, then my grass would grow
properly."
Now you want to design an
experiment that can be used to test your hypothesis. It is important that your
experiment be controlled, that you keep all conditions between groups the same, except for
that condition which you are testing. It is also important that you conduct your
experiment on several different samples, so that your results may prove conclusive.
4. Test the
hypothesis. "I took
200 small pots and used them to grow 200 samples of grass. I split the 200 pots into
5 groups of 40, and I adjusted the pH of the soil with calcium oxide (lime) until the five
groups had pH readings of; 3,5,7,9, and 11 respectively. In all of the samples I used the
same amount and type of soil and the same type and number of grass seeds. Each
sample was kept in the same room with identical conditions as far as light, temperature
and water."
If you conduct your experiment
carefully, you will probably find differences between the groups of grass that you grew.
If don't see anything that leads you to believe that the higher pH would
cause growth problems in your lawn, then you may reject your original hypothesis and form
a new one, maybe one that is based on the difference in sunlight. If your experiment
supports your hypothesis, then you may be on to something, but more testing would be
required before you could say for sure.
In real life, by the time you were
done with the above experiment, it may be winter and you would no longer be worried about
your lawn. It is not a realistic way of solving this problem, when it would be much
easier to ask a gardener about the problem, or read more about lawn care. Although
the experiment may not carry over realistically, the scientific method does. You
would still want to change only one thing at a time, when trying to improve the grass in
that area. The lesson is that all problems should be approached in a logical
manner.
Now, be sure to
check out the worksheets
and the online
quizzes!
