The period of a pendulum is the time taken for the pendulum to complete one swing. As the pendulum swings, its direction of motion alternates. It must be remembered that at the start and end of timing for a swing, the pendulum must be traveling in the same direction. Below are three diagrams showing the timing of a period for different beginning and end positions:
1. Start/stop at top of swing
2. Start/stop between top and bottom of swing
3. Start/stop at bottom of swing
a) While theoretically, periods measured using each of these start/stop positions must be the same, can you think of an experimental reason (perhaps more than one) why one of these start/stop positions would give more reliable periods?
b) Are there any modifications/additions to your apparatus that would reduce the impact of this reason(s) on the periods? What are these modifications/additions (if any) and how would they improve the measurement of period?