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 is almost steady
Your description of the rhythm of the pendulum when tilted 'forward'
the sounds get closer together
Your description of the process used to keep the rhythm steady and the results you observed:
I placed some paper under the end of the bracket toward the hanging pearl.
The rhythm was steady, and hit the bracket about 12 times
Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time:
After the first 45 deg turn the rhythm sped up
The second 45 deg turn the rhythm slowed
The third 45 deg turn, the rhythm slowed
The fourth 45 deg turn the rhythm slowed
The fifth 45 deg turn the rhythm increased
The sixth 45 deg turn the rhythm increased
The seventh 45 deg turn the rhythm increased
The eighth 45 deg turn the rhythm increased
Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm:
I think the most regular beat of the pendulum occurred when the bracket was facing down the slope of the book
Your report of 8 time intervals between release and the second 'hit':
.516
.531
.531
.484
.5
.453
.469
.5
Your report of 4 trials timing alternate hits starting with the second 'hit':
.609, .641, .703
.594, .595, .75
.609, .672, .672
.609, .656, .687, .781
The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous):
7 cm
Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging:
.61, .64, .7
Your description of the pendulum's motion from release to the 2d hit:
Between release and the first hit, the motion was not very smooth.
Your description of the pendulum's motion from the 2d hit to 4th hit:
This motion was smoother and shorter than the first one.
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 was much faster than the motion between release and the second hit.
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:
It was a slower motion than the motion between the fourth and sixth hit.
Your conjecture as to why a clear difference occurs in some intervals vs. others:
Because the pendulum traveled a shorter distance between hits.
What evidence is there that subsequent intervals increase, decrease or remain the same:
Decrease
What evidence is there that the time between 'hits' is independent of the amplitude of the swing?
This supports that the length of the swing is independent of the length, because the time does not increase if the pendulum's length is increased, the time of the swing does increase however if the pendulum is facing down an uneven surface.
Very good, but note the following correction in your terminology: The length of the pendulum was 7 cm, as you reported it, and your data were very consistent with a 7 cm pendulum.
When you used the word 'length' in the present response, I believe you were referring to amplitude, which is the distance from the equilibrium position at the center of the swing (which would presumably be the position when striking the bracket) to the furthest displacement away from the position.
The amplitude was decreasing with each 'hit', and the fact that the 'beats' remained constant indicates that the period of the swing does not change with ampitude.
about 45 mins
Very good work. Be sure to see my one note.