1. SNC1L
Scientific variables

2. Variables
A variable is anything in an experiment that may be changed. Ex. the number of paper clips attached to the paper helicopter

3. Variables Most experiments change only two: the manipulated variable
(also called the independent variable)
is the variable changed by the experimenter.
Ex. the weight of the paper

4. Variables Most experiments change only two: the responding variable
(also called the dependent variable)
is the variable measured by the experimenter.
Ex. flight time

5. Variables: Example 1
For the Question, “Does toast hit the floor butter-side down more often than it hits non-butter-side down?” The manipulated variable is the ______. The responding variable is the ______.

6. Variables: Example 1
For the Question, “Does toast hit the floor butter-side down more often than it hits non-butter-side down?” The manipulated variable is the butteriness. The responding variable is the ______.

7. Variables: Example 1
For the Question, “Does toast hit the floor butter-side down more often than it hits non-butter-side down?” The manipulated variable is the butteriness. The responding variable is the number of times that side hits the floor.

8. Variables: Example 2
For the Question, “How does changing the mass of a pendulum affect the time it takes to swing?” The manipulated variable is the ______. The responding variable is the ______.

9. Variables: Example 2
For the Question, “How does changing the mass of a pendulum affect the time it takes to swing?” The manipulated variable is the mass. The responding variable is the ______.

10. Variables: Example 2
For the Question, “How does changing the mass of a pendulum affect the time it takes to swing?” The manipulated variable is the mass. The responding variable is the time.

11. Variables
All other variables that are kept the same are called controlled variables.

12. Variables
All other variables that are kept the same are called controlled variables. In the butter-side experiment, what would you have to control?

13. Variables
All other variables that are kept the same are called controlled variables. In the butter-side experiment, what would you have to control? the size of the toast, how browned the toast is, the height from which it is dropped, etc.

14. Variables
All other variables that are kept the same are called controlled variables. In the pendulum experiment, what would you have to control?

15. Variables
All other variables that are kept the same are called controlled variables. In the pendulum experiment, what would you have to control? the angle from which the pendulum is dropped, the length of the pendulum, etc.

16. Experimental Error
Because you can never control everything completely (what if there’s a wobble in the pendulum?), you should perform multiple trials and average the results. This reduces the effect of experimental error (error beyond the experimenter’s control).

17. Paper Helicopters Part 2
Today’s Question is, “How does the length of the rotor blades affect the flight time of your paper helicopter?” The manipulated variable is the ______. The responding variable is the ______.

18. Paper Helicopters Part 2
Today’s Question is, “How does the length of the rotor blades affect the flight time of your paper helicopter?” The manipulated variable is the blade length. The responding variable is the ______.

19. Paper Helicopters Part 2
Today’s Question is, “How does the length of the rotor blades affect the flight time of your paper helicopter?” The manipulated variable is the blade length. The responding variable is the flight time.

20. Paper Helicopters Part 2
Today’s Question is, “How does the length of the rotor blades affect the flight time of your paper helicopter?” What variables would you have to control?