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The Scientific Method
Science 9
Scientific
Method
A science project is an
investigation using the scientific method to discover the answer to a
scientific problem. Before starting your project, you need to understand the
scientific method. This sheet uses examples to illustrate and explain the basic
steps of the scientific method. The scientific method is the "tool"
that scientists use to find the answers to questions. It is the process of
thinking through the possible solutions to a problem and testing each
possibility to find the best solution. The scientific method involves the
following steps (in order): doing
research, identifying the problem, stating a hypothesis, conducting project
experimentation, and reaching a conclusion.
Research is the process of
collecting information from your own experiences, knowledgeable sources, and
data from exploratory experiments. Your first research is used to select a
project topic. This is called topic research. For example, you observe a
black growth on bread slices and wonder how it got there. Because of this
experience, you decide to learn more about mold growth. Your topic will be
about fungal reproduction. (Fungal refers to plant-like organisms called
fungi, which cannot make their own food, and reproduction is the making
of a new offspring.) CAUTION: If you are allergic to mold, this is not a topic
you would investigate. Choose a topic that is safe for you to do.
After you have selected a
topic, you begin what is called project research. This is research to
help you understand the topic, express a problem, propose a hypothesis, and
design one or more project experiments—experiments designed to test the
hypothesis. An example of project research would be to place a fresh loaf of
white bread in a bread box and observe the bread over a period of time as an
exploratory experiment. The result of this experiment and other research give
you the needed information for the next step—identifying the problem.
Do use many references from printed sources—books, journals, magazines,
and newspapers—as well as electronic sources—computer software and online
services.
Do gather information from professionals—instructors, librarians,
and scientists, such as physicians and veterinarians.
Do perform other exploratory experiment related to your topic.
Problem
The problem is the scientific question to be solved. It is best expressed as an
"open-ended" question, which is a question that is answered with a
statement, not just a yes or a no. For example, "How does light affect the
reproduction of bread mold on white bread?"
Do limit your problem. Note that the previous
question is about one life process of molds—reproduction; one type of mold—bread
mold; one type of bread—white bread; and one factor that affects its
growth—light. To find the answer to a question such as "How does light
affect molds?" would require that you test different life processes and an
extensive variety of molds.
Do choose a problem that can
be solved experimentally. For example, the question "What is a mold?" can be
answered by finding the definition of the word mold in the dictionary.
But, "At room temperature, what is the growth rate of bread mold on white
bread?" is a question that can be answered by experimentation.
Hypothesis
A hypothesis is an idea about the solution to a problem, based on knowledge and
research. While the hypothesis is a single statement, it is the key to a
successful project. All of your project research is done with the goal of
expressing a problem, proposing an answer to it (the hypothesis), and designing
project experimentation. Then all of your project experimenting will be
performed to test the hypothesis. The hypothesis should make a claim about how
two factors relate. For example, in the following sample hypothesis, the two
relating factors are light and bread mold growth. Here is one example of a
hypothesis for the earlier problem question:
"I believe that bread mold does not need
light for reproduction on white bread. I base my hypothesis on these facts:
Do state facts from past
experiences
or observations on which you base your hypothesis.
Do write down
your hypothesis before beginning the project experimentation.
Don't change your
hypothesis even if experimentation does not support it. If time permits, repeat
or redesign the experiment to confirm your results.
Project
Experimentation
Project experimentation is
the process of testing a hypothesis. The things that have an effect on the
experiment are called variables. There are three kinds of variables that you
need to identify in your experiments: independent, dependent, and controlled.
The independent variable
is the variable you purposely manipulate (change). The dependent variable
is the variable that is being observed, which changes in response to the
independent variable. The variables that are not changed are called controlled
variables.
The problem in this
section concerns the effect of light on the reproduction of bread mold. The
independent variable for the experiment is light and the dependent variable is
bread mold reproduction. A control is a test in which the independent variable
is kept constant in order to measure changes in the dependent variable. In a
control, all variables are identical to the experimental setup—your original
setup—except for the independent variable. Factors that are identical in
both the experimental setup and the control setup are the controlled variables.
For example, prepare the experiment by placing three or four loaves of white
bread in cardboard boxes the size of a bread box, one loaf per box. Close the
boxes so that they receive no light. If, at the end of a set time period, the
mold grows, you might decide that no light was needed for mold reproduction.
But, before making this decision, you must determine experimentally if the mold
would grow with light. Thus, control groups must be set up of bread that
receives light throughout the testing period. Do this by placing an equal
number of loaves in comparable-size boxes, but leave them open.
The other variables for
the experimental and control setup, such as the environmental conditions for
the room where the boxes are placed—temperature and humidity—and the brand of
the breads used must be kept the same. These are controlled variables. Note
that when designing the procedure of your project experiment, you must include
steps for measuring the results. For example, to measure the amount of mold
growth, you might draw 1/2-inch (1-cm) squares on a transparent sheet of
plastic. This could be placed over the bread, and the number of squares with
mold growth could be counted. Also, as it is best to perform the experiment more
than once, it is also good to have more than one control. You might have one
control for every experimental setup.
Do have only one independent variable during an experiment.
Do repeat the experiment more than once to verify your results.
Do have a control.
Do have more than one control, with each being identical.
Do organize data. (usually in table format)
The project conclusion is a summary of the results of the project
experimentation and a statement of how the results relate to the hypothesis.
Reasons for experimental results that are contrary to the hypothesis are
included. If applicable, the conclusion can end by giving ideas for further
testing.
If your results do not
support your hypothesis:
DON'T change your hypothesis.
DON'T leave out experimental
results that do not support your hypothesis.
DO give possible reasons for
the difference between your hypothesis and the experimental results.
DO give ways that you can
experiment further to find a solution.
If your results support
your hypothesis:
You might say, for
example, "As stated in my hypothesis, I believe that light is not
necessary during the germination of bean seeds. My experimentation supports the
idea that bean seeds will germinate without light. After seven days, the seeds
tested were seen growing in full light and in no light. It is possible that
some light reached the 'no light' containers that were placed in a dark closet.
If I were to improve on this experiment, I would place the 'no light'
containers in a light-proof box and/or wrap them in light-proof material, such
as aluminum foil."
3 Easy
Steps to Selecting a Topic
1. Think
of a topic you're interested in. For example:
2. Of course, you could develop a hundred projects
on any one of those topics. Now try to focus on one aspect of one topic
in particular. For example:
3. Now use this same idea, but
be more specific. What would you really like to figure out or
show? Think of the most exact information you can discover and be very specific.
In science, information has to be exact if it's really going to matter. For
example: