pearl pendulum

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 sounds get further apart. The rhythm gets slower.

When I released the pearl it bounced several times beginning with a louder sound and the sound them fadded with each bounce. The rhythm slowed with each bounce also.

** Your description of the rhythm of the pendulum when tilted 'forward' **

It strikes the bracket less and less frequently. The rhythm becomes slower. I released the pearl and it immediatley began to bounce but every bounce was slower which made the rhythm become slower also.

** Your description of the process used to keep the rhythm steady and the results you observed: **

I first placed two quarters under the back leg of the bracket. This did not produce a steady rhythm, so I removed one of the quarters and it them produced a steady rhythm.

** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **

The sounds get further apart.

The sounds continue to get furthr apart.

The sounds get closer together.

The sounds remain closer together until gets back to its original position after rotating 45 degrees 5 more times.

** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **

The pendulum would have to be on a perfectly level flat surface.

** Your report of 8 time intervals between release and the second 'hit': **

.906

.578

.5

.625

.296

.328

.672

.406

Each interval is the time it took the pendulum to strike the second time after being released. I used the timer program to get the times.

** Your report of 4 trials timing alternate hits starting with the second 'hit': **

.656,.719,.906

.391,.438,.641

.531,.547,.672,.766

.516,.469,.891

The first, second, and fourth trial only had 3 intervals where the third trial had 4 intervals. The results were obtained with the timer program. The results are the time intervals for every second time that the pendulum strikes the bracket.

** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **

7cm

** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **

.66,.63,.19

** Your description of the pendulum's motion from release to the 2d hit: **

It swings and strikes the bracket and swings back out.

Good start, but then it swings back before hitting the bracket. That's 'in', 'out', 'in'.

** Your description of the pendulum's motion from the 2d hit to 4th hit: **

It swings, strikes the bracket, and is obviously slowing down.

I would say that it 'out', 'in', 'out', 'in'.

** 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: **

It slows down considerably between each hit.

if you count 'out's' and 'in's' as partial cycles then there are a total of four partial cycles between 2d and 4th 'hit', and three partial cycles between release and 2d 'hit'.

The pendulum does indeed slow down, but if its rhythm is steady the time for each of these partial cycle will be the same as for any other.

** 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: **

The motion between the second and fourth hit is faster than the motion between the fourth hit and the sixth hit.

** Your conjecture as to why a clear difference occurs in some intervals vs. others: **

Because the pendulum is swinging faster at that point.

** What evidence is there that subsequent intervals increase, decrease or remain the same: **

Subsequent intervals will decrease.

** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **

It proves that the longer the length of the pendulum the slower the swing and lessens the distance it swings.

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45 minutes

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See my notes and be sure you understand them. Let me know if you have questions.