Problem/Question
Observation/Research
Formulate a Hypothesis
Experiment
Collect and Analyze Results
Conclusion
Communicate the Results
Steps of the
Scientific Method
Independent Variable
The independent variable is a
factor that the experimenter
changes. (on x-axis)
John is going to use 25g., 50g.,
100g., 250g., 500g. of sugar in
his experiment.
Dependent Variable
The dependent variable is the
factor that may change as a
result of changes made in the
independent variable. (on Yaxis)
It is what we measure!
Control Group
The control serves as a standard
of comparison.
You do nothing to this group!
All experiments should have this!
Constants
All other factors stay the
same so that any
observed changes can
be attributed to the
independent variable.
Trials
It is how many times
you do the
experiment.
A Little Practice with the Scientific
Method
The next slide is a Bart Simpson scenario.
Read it carefully, and see whether you can
answer the associated questions.
Bart Simpson believes that mice exposed to microwaves will become
extra strong (maybe he’s been reading too much Radioactive Man).
He decides to perform this experiment by placing 10 mice in a
microwave for 10 seconds (do not do this at home, Bart is a
misguided fictional character ). He compared these 10 mice to
another 10 mice that had not been exposed. His test consisted of a
heavy block of wood that blocked the mouse food. He found that 8
out of the 10 microwaved mice were able to push the block away. 7
out of 10 non-microwaved mice were able to do the same.
1.  What was Bart’s hypothesis?
2.  Identify the Control group.
3.  Identify the independent and dependent variables
4.  What might be some of the possible constants?
5.  What should Bart’s conclusion be?
ANSWERS
1.  Mice exposed to microwaves will be
extra strong
2.  The unexposed mice
3.  Independent variable- microwaves
Dependent variable- strength
4.  Same block of wood, same food, time of
day, approx same size mice, etc.
5.  Microwave exposure does not
significantly change the strength of mice.