phy121
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 rhythm seems to get faster.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sounds in this case get further apart.
** Your description of the process used to keep the rhythm steady and the results you observed: **
In order to make the rhythm steady, I had to put a paper folded to four thicknesses under the back end of the bracket.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
On a level table, I placed one domino under each of the top left and right corners of my closed textbook, with the front cover upward. I placed the bracket pendulum on the middle of the book, with the base of the bracket parallel to one of the sides of the book, and the pearl facing the bottom edge of the book. I released the pendulum and found that the sounds got further apart. I turned the bracket pendulum 45 degrees clockwise, and released the pendulum. This time, the sounds got closer togehter. I turned the bracket pendulum another 45 degrees clockwise, and again released the pendulum. The sounds got closer together. Once again, I turned my apparatus 45 degrees clockwise. The sounds got closer together. The final 45 degree turn returned the bracket pendulum to its original position.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
To obtain the most regular beat of the pendulum, I would orient it so that the pearl hung at its equalibrium position to start.
** Your report of 8 time intervals between release and the second 'hit': **
.539
.523
.492
.500
.539
.500
.500
.492
Each number in the lines above represents the time in seconds beginning at the release of the pendulum and ending with the second hit of the bracket.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.641,.336, .484, .297
.664, .516, .578, .453
.664, .445, .672, .484
.492, .484, .570, .468
The numbers listed above list four separate trials where I started the timer at the release of the pearl, then timed the second hit, the fourth, the sixth, then the eighth. The times are measured in seconds.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
8.7 cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.615,.445,.576,.426
** Your description of the pendulum's motion from release to the 2d hit: **
1
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
2
From release, the first hit occurs at the first interval, and from the first hit the pendulum returns to extreme point, then hits the second time. This represents two of the described intervals.
** 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: **
From release to second hit is three intervals, but from second hit to fourth hit is four intervals. This is because the pendulum starts at the extreme point in the first scenerio, and the equilibrium point in the second scenerio.
Good.
** 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 fourth hit to the sixth hit and the second hit to the fourth hit are the same number of intervals because they represent the same start and end point.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
The latter intervals will be longer because the pendulum will slow down before ultimately coming to a stop.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
The subsequent time intervals should increase.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
My release points were somewhat inconsistent, and yet the interval times remained very similar. This supports the hypothesis that the length of a pendulum's swing depends only on its length.
** **
45 minutes
** **
&#Your work looks good. See my notes. Let me know if you have any questions. &#