1. Control, Independent, Dependent Variables Workshop
15 Practice Problems

2. Steps to find the variables
When trying to find the variables, ask yourself:
1. What two “things” are being observed/measured?
2. Out of those two, which one is dependent on the other?
3. Now that you know what is dependent, which of those two is independent?
4. Look for the control variable: “What won’t change in this experiment?

3. Strategies to find the variables (Example)
Example: If you increase the amount of milk you drink, then you will increase the strength of your bones.
1. What two things are being observed?
Amount of milk and strength of bones.
2. Out of those two things, which one is dependent on the other?
The strength of your bones depends upon the amount of milk you drink.
3. Now that you know what is dependent, which of those two things is independent?
The amount of milk
4. Look for the control variable: “What won’t change in this experiment?
Type of milk

4. A Quick Recap… use your notes to quickly define these three terms…
Control Variable:
Variable(s) that can not be changed.
2. Independent Variable:
Variable(s) that can be changed by the scientist – not affected by the dependent variable.
3. Dependent Variable:
Variable(s) that are changed by the independent variable.

5. 4. Mrs. McNiece wanted to see how different types of music affected students' pulse rates. She played different types of music: heavy metal, rap, R&B, alternative, pop, country, and classical music. What should the control be for this experiment?
Types of music
Using a different kind of music
Use all dead people
Play the different music for the same length of time

6. 5. Mario studied how far room temperature water would spurt out of a plastic milk carton when 3mm holes were punched at different heights from the bottom of the container. Identify the dependent variable.
3 mm holes
The temperature
The distance the water traveled.
The plastic milk cartons

7. 6. Nick wanted to see how high an ice cube would float in different temperatures of water. Identify the independent variable.
Height of the ice cube
Temperature of the water
The Water
The amount of water

8. 7. Tiffany was investigating how fast it took Hayden to react to different sounds. Identify the dependent variable.
Hayden
Hayden’s time reacting to sound
The sounds made

9. 8. Justin usually blows his nose using Kleenex tissues
8. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue.
He decided he is going to create an experiment to find out if there is something better.
What is the independent variable in the first part?
The amount of tissue
The amount of snot
Type of tissue
Kleenex
Justin

10. 9. An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.
Control Variable (CV):
Dependent Variable (DV):
Independent Variable (ID):

11. 10. If you increase the number of cigarettes you smoke, then you will increase your risk for lung cancer.
Control Variable (CV):
Dependent Variable (DV):
Independent Variable (ID):

12. 11. If you increase the amount of blood in the water, then you will increase the number of sharks in the area.
Control Variable (CV):
Dependent Variable (DV):
Independent Variable (ID):

13. 12. The higher the temperature of water, the faster an egg will boil.
Control Variable (CV):
Dependent Variable (DV):
Independent Variable (ID):

14. 13. If you increase the amount of milk you drink, then you will increase the strength of your bones.
Control Variable (CV):
Dependent Variable (DV):
Independent Variable (ID):
14. If you increase the number of hours you spend in practice, then you will increase the number of free throw shots you will make.

15. Then they will run for 2 minutes and I will check their heart rate.
15. John is doing a test to see if there is a connection between how long you run and how fast your heart beats.
John will be performing an experiment where a person will run for a 1 minute and John will check their heartbeat.
Then they will run for 2 minutes and I will check their heart rate.
John will do this up to 6 minutes and see if there is a connection.
What are John’s variables?
Control Variable (CV):
Dependent Variable (DV):
Independent Variable (ID):