Scientists all over the world use a common process for performing their
experiments. This process is called the scientific method. In the scientific
method, researchers review background literature, state the problem,
form a hypothesis, design and do the experiment, collect data, analyze
it, and draw conclusions. Examine the chart below for more information
about each step.
| Step |
Description |
Example |
Image |
| Review background information |
Scientists look for research that has already been
done on their topic to determine if they are duplicating a past
experiment, doing something new, or building on a previous experiment.
Much of the research can be done using the Internet. |
If I wanted to keep astronauts safe on long trips
in space, I would review the research that NASA’s life scientists
have already done. I would find that the immune system is affected
in astronauts and that it is often studied in smaller animals like
fruit flies. |
Drosophila melanogaster, or common fruit fly, sitting on a piece
of melon skin. |
| State the problem |
Once scientists have an idea of the research question
they want to study, they state the problem. |
How does the space environment affect fruit flies’
immune systems? |
A Drosophila melanogaster larva fluorescently labeled to visualize
the nervous system. |
| Form a hypothesis |
A hypothesis is a statement of what the researcher
thinks will happen in the experiment. It must be observable and
testable. |
Since immune suppression leads to increased bacterial
infections, fruit flies exposed to the space environment will be
more susceptible to bacterial infections than fruit flies not exposed
to the space environment. |
Fly chambers in Experiment Research Module. |
| Design and do the experiment |
When designing the experiment, the researcher carefully
controls as many variables as possible. In most experiments there
is a control group and a treatment group. The two groups are as
similar as possible, but the treatment group is the one that experiences
the variable that you’re studying. |
In the Flies in Space experiment, scientists
will perform a ground experiment with the same equipment, fruit
fly food, procedures, temperature, and schedule as the flies in
space. This is the control group. The experimental group is made
up of the flies that travel on the space shuttle. The only difference
between the two groups is whether or not they were in space. All
of the flies will be exposed to bacteria on Earth after the space
travel. |
Doing an experiment during the Hyper-G high school team biology
competition. |
| Collect and analyze data |
An important part of research is collecting data.
After the data are collected, they are analyzed. This step often
involves organizing data in charts and graphing it. |
In this experiment, data will be collected about
how much bacteria the flies were exposed to, and the number of flies
that showed negative effects from the bacteria. |
Data collection during the Hyper-G high school team biology experiment. |
| Draw conclusions |
After the data are analyzed, scientists see if the
results support their hypothesis. Even if the hypothesis is not
correct, conclusions can still be made and significant knowledge
gained. |
Depending on the data about how flies react to the
bacteria, scientists will evaluate their hypothesis to determine
if space travel affected the flies’ immune system. |
A team of researchers looks on as a beaker of fruit flies is analyzed. |
