Your work on pearl pendulum 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'
When the pendulum is tilted, the pearl hits the metal more and more frequently as it comes closer to its resting position on the metal. The rythym gets faster.
Your description of the rhythm of the pendulum when tilted 'forward'
The sounds definitely get farther apart as the pearl's resting place is away from the metal. The rythym slows down significantly.
Your description of the process used to keep the rhythm steady and the results you observed:
I pulled the pearl out to an approximately 90 degree angle and dropped it. I continually added pieces of paper to act as shims until the rhythym seems to level out. It is not perfect, but I believe it is close. the pearl hit 18 times before stopping.
Your description of what happened on the tilted surface, rotating the system 45 degrees at a time:
The pendulum begins at the 6:00 position and the pearl's rhythym decreases as time passes. As the bracket is turned counterclockwise towards the 12:00 position, the rhythym increases after the bracket has passed the 3:00 position. At the 3:00 position, the rhythym is constant since the angle of the surface holds little bearing on the direction of momentum of the pearl. As the bracket continues past 9 and back to 6, the opposite holds true. the rhythym slows as the angle of the surface holds more of an effect.
Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm:
orient the bracket perpendicular to the angle of the surface. If the angle of the surface goes from north to south (such as the book) then orient the bracket in an east-west direction.
Your report of 8 time intervals between release and the second 'hit':
2 .492
3 .379
4 .281
5 .289
6 .313
7 .277
8 .352
9 .281
Your report of 4 trials timing alternate hits starting with the second 'hit':
2 2751.277 .5546875
3 2751.914 .6367188
4 2752.617 .703125
5 2753.227 .609375
6 2753.867 .640625
7 2754.5 .6328125
8 2755.121 .6210938
9 2755.77 .6484375
10 2756.422 .6523438
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:
.55, .64, .70
Your description of the pendulum's motion from release to the 2d hit:
There is a greater distance in the first drop and hit than in any of the others.
Your description of the pendulum's motion from the 2d hit to 4th hit:
The first hit takes a fair amount of the energy of the pearl away and so the second hit does not go as far.
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:
Every time the pearl hit the bracket, it loses a little bit of energy from the initial drop and therefore slows down until it finally stops.
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 sixth hit will have the least amount of energy behind it because it has had 5 hit before it to absorb the energy.
Your conjecture as to why a clear difference occurs in some intervals vs. others:
the pearl gains the most speed on the initial drop. the rest of the hits must have the pearl swing out AND back in before it hits. the initial one only goes one way.
What evidence is there that subsequent intervals increase, decrease or remain the same:
since the pendulum in theory is not effected by the angle of the book it is sitting on, we would hope that the rhythym would stay essentially the same. It will eventually slow down because of the friction in the system.
What evidence is there that the time between 'hits' is independent of the amplitude of the swing?
this supports that the farther it swings will affect it. by it swinging, the pendulum regains some speed of momentum to keep going. the longer it is, the longer it can swing. if it was only a 1 cm pendulum, it would not swing for very long at all. 1 meter would swing for much longer.
Good data.
After the due date we will be discussing this experiment further via an online forum.