Download Practice- Independent and Dependent Variables

Practice- Manipulated and Responding Variables
Manipulated Variable: The variable that the scientist changes in the experiment.
Responding Variable: The variable that changes in RESPONSE to the manipulation. The responding
varibable MUST BE MEASURABLE!
Sample Problem: A scientist want to study the diversity of soil bacteria found during different
months of the year.
a. What is her manipulated variable? _______________________________________
b. What will be her responding variable? ____________________________________
Questions. Identify the manipulated and responding variables in the following examples.
1.
Height of bean plants is recorded daily for 2 weeks.
a. manipulated variable: ________________________________________________
b.
2.
Guinea pigs are kept at different temperatures for 6 weeks. Percent weight gain is recorded.
a. Manipulated variable: ________________________________________________
b.
3.
Responding variable: _________________________________________________
Batches of seeds are soaked in salt solutions of different concentrations and germination is counted for each
batch.
a. Manipulated variable: ________________________________________________
b.
6.
Responding variable: _________________________________________________
Light absorption by a pigment is measured for red, blue, green, and yellow light.
a. Manipulated variable: ________________________________________________
b.
5.
Responding variable: _________________________________________________
The diversity of algal species is calculated for a coastal area before and after an oil spill.
a. Manipulated: ________________________________________________
b.
4.
Responding variable: _________________________________________________
Responding variable: _________________________________________________
An investigator hypothesizes that the adult weight of a dog is higher when it has fewer littermates.
a. Manipulated variable: ________________________________________________
b.
Responding variable: _________________________________________________