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 closer together.
I heard the ball bouncing off the bracket and it sounded like the sounds were speeding up.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sounds get further apart. I heard the ball hitting the bracket but the sounds seemed further apart.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I placed the bracket on my opened textbook and raised the end that had the ball with a Christmas card in an envelope.
The rhythm was steady until the last few hits on the bracket. The pendulum hit the bracket 15 times.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
Parallel to side = sounds further apart
Rotated 45degrees,ball facing myself= closer together
Rotated 45degrees to parallel side of book, ball facing the opening of book=closer together
Rotated 45degrees to ball facing away from me=further apart
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
Orient the bracket so that the part that the ball hits is parallel to the side of the book.
** Your report of 8 time intervals between release and the second 'hit': **
.516
.500
.672
.688
.688
.625
.641
.609
I found the interval between the letting go of the ball and when it hit the bracket for the second time.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.781,.641,.641,.719
.781,.672,.656,.672
.672,.750,.689,.719
.689,.689,.656,.734
These are the time intervals between every other bounce for four separate letting go of the ball.
I took the intervals obtained at second bounce. I skipped the first bounce then timed the 2nd, 4th, 6th,etc bounces.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
9.5cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.731,.677,.661
** Your description of the pendulum's motion from release to the 2d hit: **
The pendulum is raised to an extreme point and travels toward the opposite extreme point until it is stopped by the bracket.
This describes release to the first 'hit'.
What happens between the first and second 'hit'?
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The pendulum travels from where the bracket was toward the first extreme point and back to hit the bracket again.
In the first hit, the bracket defines how far the pendulum may reach, in the second, it defines where the pendulum starts.
This would describe the first 'hit' to the second, or the second to the third, but does not cover the time from the 2d to the 4th 'hit'.
You can easily add the rest of the description (e.g., in this case it does as you described, repeating the process twice; what is the difference betweeen this and the motion between release and the second 'hit'?).
** 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 motion of the release to the second hit differs from the second to fourth hit because in the release, the bracket is only defining how far the pendulum may go before stopping, in the second to fourth hit, the pendulum affects how far the pendulum may go away from the bracket and it is the way to stop it.
** 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 hit and the fourth hit is like the motion between the fourth and sixth hit in that they are both starting from the bracket and bouncing back and also returning to the bracket.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
There would be more force from the pendulum being released and allowed to hit the bracket than from the bracket determining the start and stop positions for the swings.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
To increase because the pendulum would not be allowed to accelerate as much as in the first time interval.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
The lengths of the swings were different even though the length of the pendulum did not vary. The distance the pendulum swings does not depend solely on the length of the pendulum.
What, therefore, was should be the ratio between the times observed from release to second 'hit' and from 2d to 4th 'hit'?
How does this compare with the time intervals you observed?
** **
1hr, 30 minutes
** **
Very good.
Take a few minutes and insert answers to my questions into a copy of this document; mark your insertions with &&&&.