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 remain constant until the pear misses.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The rhythm remains constant with each bounce, until the pearl misses.
** Your description of the process used to keep the rhythm steady and the results you observed: **
To make the rhythm stead I had to make the bracket tilt slightly forward, so that the back of the bracket is approximately 2cm off the flat surface.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
0 (degrees) (pear facing the top of the book) - the sounds get closer together
45 - the sounds get closer together but at a slower rate
90 - the sounds get closer together, but only slightly
135 - the sounds remain fairly constant, getting closer together very slightly
180 (pear facing the bottom of the book)- the sounds remain constant.
The rest of the turns follow the same pattern reversed.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
at 180 degrees.
** Your report of 8 time intervals between release and the second 'hit': **
TRIAL 1 - 0.453,0.344,0.328,0.313,0.297,0.344,0.313,0.328,0.344,0.359,0.344,0.344,0.359,0.375,0.406,0.391,0.422,0.406,0.391,0.469,0.438,0.453,0.5
TRIAL 2 - 0.484,0.375,0.359,0.328,0.313,0.375,0.344,0.328,0.344,0.359,0.313,0.328,0.344,0.359,0.344,0.344,0.375,0.375,0.375,0.359,0.391,0.438,0.484,0.406,0.547,0.422.
TRIAL 3 - 0.422,0.328,0.328,0.359,0.328,0.328,0.344,0.313,0.344,0.359,0.344,0.344,0.375,0.375,0.391,0.406,0.406,
TRIAL 4 - 0.391,0.391,0.344,0.359,0.359,0.344,0.328,0.359,0.328,0.344,0.344,0.344,0.406,0.344,0.391,0.359,0.375,0.375,0.375,0.406,0.578.
TRIAL 5 - 0.391,0.313,0.328,0.328,0.344,0.359,0.328,0.375,0.328,0.313,0.344,0.375,0.359,0.359,0.359,0.422,0.516,0.547.
TRIAL 6 - 0.422,0.359,0.344,0.344,0.359,0.359,0.344,0.328,0.375,0.328,0.359,0.328,0.344,0.344,0.359,0.344,0.391,0.406,0.469.
TRIAL 7 - 0.406,0.344,0.328,0.359,0.359,0.359,0.344,0.344,0.359,0.344,0.344,0.375,0.344,0.359,0.328,0.406
TRIAL 8 - 0.406,0.344,0.344,0.359,0.328,0.313,0.391,0.328,0.344,0.359,0.344,0.359,0.344,0.406,0.422.
These numbers represent the intervals at which the pendulum hit the bracket, starting at the second hit.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
TRIAL 1 - 0.438,0.703,0.625,0.656,0.672,0.672
TRIAL 2 - 0.391,0.656,0.625,0.672,0.656,0.719,0.719,0.688
TRIAL 3- 0.406,0.656,0.672,0.672,0.656,0.672,0.688,0.688
TRIAL 4 - 0.391,0.718,0.672,0.656,0.672,0.641,0.656.
TRIAL 5- 0.5,0.609,0.641,0.641,0.672,0.672,
0.703
TRIAL 6 - 0.453,0.688,0.672,0.625,0.656,0.672,0.75,0.734
TRIAL 7 - 0.313,0.734,0.672,0.672,0.688,0.656,0.688,0.734
TRIAL 8 - 0.359,0.719,0.656,0.688,0.672,0.656,0.719
These are the intervals at which the pendulum hit the bracket, starting on the second, and recording every 2 hits.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
96mm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
0.41,0.68,0.65
** Your description of the pendulum's motion from release to the 2d hit: **
The pendulum is realeased from the extreme point and then hits the bracket for the first hit. This is 1/2 of a full cycle.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
Betweent he first and the second hit, the pendulum goes through the extreme and back to hit the bracket. This is the length of a full cycle.
** 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 release and the second hit have 1.5 cycles between them; whereas, the second and forth hit have 2 whole cycles between them.
review the description given in the experiment of a cycle; I believe that the correct results are half of what you report: 3/4 cycles and 1 cycle. It appears that what you call a cycle is in fact a half-cycle.
This doesn't affect the ratio of these times, which is 4/3 either way.
** 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 no difference.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
It should be shorter becuase there is a .5cycle difference in the travel length.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
Stay the same.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
This experiment shows that the length of a pendulums swing does only depend on its length, not how far it swings, becuase each trial produces approximately the same time for each swing, even though they swing at different distances.
** **
70 minutes
** **
Accurate data can be hard to get for this experiment; accurate timing would in fact show the 4/3 ratio. Experimental error made your data too 'noisy' to distinguish this result.
Your analysis is very good.
See my notes.