## Doing Experiment A

Here are ideas from the video on Experiment A that bear repeating:
1. Whenever the lever arm is depressed to the same point (the horizontal in Experiment 8), the same force has been applied to the rubber band. In both this experiment and the experiments of Lesson 9, students find they can exert the same force on the rubber band by pushing the lever arm with different forces, at different points.
2. Always depress the lever arm to the horizontal, not beyond.
3. If the lever arm is not angled up (so it can be depressed to the horizontal), lower the rivet to which the rubber band is attached.
4. Hold the Force Probe at a place where it will not buckle at the 11"  mark, but will begin to buckle at the 9" mark.  (Do not hold the Force Probe where indicated on the Force Probe Template!!!)
5. Hold the Force Probe at this same point at each position on the lever arm: 11', 9", 7" and so forth.  Students will want to change the position they are holding Force Probe so it will not buckle.
6. Emphasize that the amount of buckling is an indication of the amount of force being exerted on the lever arm through the Force Probe.
7. The Force Probe is  the input link.