Your 'pearl pendulum' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Your general comment, if any: **
** Your description of the rhythm of the pendulum when tilted 'back' **
The sound gets closer together as it has to swing back upward where it loses momentum and contacts the metal more and more often.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sound gets further apart as the pearl has to go upward and lose momentum away from the metal.
** Your description of the process used to keep the rhythm steady and the results you observed: **
The longer the thread was let out to make the pearl lower to the surface affected how many times it struck the metal. Also, the height to which the pearl was lifted affected the number of times it struck. Holding the pearl parallel to the surface, the pearl bounced about 12 times.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
In the first position with the bracket tilted slightly forward, the sounds get slightly further apart, but it's hard to distinguish until the end. At the first 45 degree shift the sound seems relatively constant. With the bracket tilted slightly backward in the next shift it gets closer together. And for the third shift the sound again seems relatively constant as the bracket is neither forward or backward.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
Place the bracket at the first or third shifted postions where the bracket swinging mechanism is level unlike the bracket itself.
** Your report of 8 time intervals between release and the second 'hit': **
.269
.241
.243
.259
.243
.233
.242
.261
These are the averages for the 8 trials and were obtained by taking the finish time and subtracting it from the start time and then averaging the total number of clicks.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.391, .297, .25, .289, .21, .256, .234
.264, .356, .256, .398, .273, .349, .262, .321
.241, .374, .353, .257, .294, .392, .377, .274, .362
.263, .352, .263, .273, .251, .263, .156, .173
These results come from the intervals between hits on the bracket and were obtained from the timer. I don't believe these are very accurate because I may not have been clicking at the exact time the pearl was hitting.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
10.7cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.318, .335, .281
** Your description of the pendulum's motion from release to the 2d hit: **
The pendulum encounters the bracket before going any further on the release.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The pendulum loses some momentum from encountering the bracket and is therefore slowed greatly.
** Your description of the difference in the pendulum's motion from release to the 2d 'hit', compared to the motion from the 2d 'hit' to the 4th hit: **
The pendulum has more momentum on the second hit compared to the fourth.
** Your description of the difference in the pendulum's motion from the 2d to the 4th 'hit' compared to the motion from the 4th to 6th hit: **
There is less and less distance that it travels to hit the bracket and hits more often.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
Because momentum is lost.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
decrease, due to the frequent encounters with the metal.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
The longer the thread, the longer it will bounce, and the shorter the thread results in more frequent hits.
** **
30 minutes
** **
Some of the questioning and instruction was a little confusing and took some time to get through. Some answers aren't given with full confidence.
You have good and useful data, but you appear to be timing every 'hit', not alternate 'hits'. Can you answer these questions for the time from release to 2d 'hit', then from 2d to 4th 'hit'?