pearl pendulum

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:

My actual data (the numbers from the timer) may not follow the findings of my experiment. It is hard to get reflexes that good. My findings reflect more of my observations.

Your description of the rhythm of the pendulum when tilted 'back'

The rhythm gets faster.

Your description of the rhythm of the pendulum when tilted 'forward'

The sounds 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 tilt the bracket forward so that the pearl would hang slightly away from the bracket. At this angle the pendulum hit the bracket 4 times.

Your description of what happened on the tilted surface, rotating the system 45 degrees at a time:

With one domino on the top right and one at the top left of the closed textbook, I observed these findings with respect to the frequency of sounds.

At the original location where the magnet end of the base is at the raised end of the textbook I observed that the sounds were getting further apart

at 45 degrees counterclockwise from the starting point, the sounds were close to the same as the previous.

at another 45 degrees counterclockwise, the sounds began to get closer together.

at another 45 degrees counterclockwise, the sounds were close to the same as those in the previous location.

at another 45 degrees, the sounds became closer together.

At another 45 degrees, the sounds remained closer together.

At another 45 degrees, the sounds once again began to fade.

At another 45 degrees the sounds were back to being far apart.

Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm:

The most regular beat is obtained by placing the pendulum parallel to the top and bottom of the book.

Your report of 8 time intervals between release and the second 'hit':

.305

.299

.336

.242

.313

.281

.320

Your report of 4 trials timing alternate hits starting with the second 'hit':

.336, .390

.281, .352

.484, .539

.601, .422

.460, .531

.507, .429

.352, .344

.570, .367

The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous):

5cm.

Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging:

.449, .421

My pendulum would only hit four times per release.

Your description of the pendulum's motion from release to the 2d hit:

The motion of the pendulum between the release and the first hit is simply the pendulum traveling down from the point of release.

Your description of the pendulum's motion from the 2d hit to 4th hit:

Between the first hit and the second hit, the pendulum must travel up, then down, whereas between the release and the first hit, the pendulum only has to travel down.

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 the release to the second hit, the pendulum must travel down, up, then down. From the second hit to the fourth hit, the pendulum must travel up, down, up, down.

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 his are the same. The pendulum travels up, down, up, down. The distance traveled just becomes less from the second hit to the fourth hit.

Your conjecture as to why a clear difference occurs in some intervals vs. others:

Because the pendulum only had to travel down.

What evidence is there that subsequent intervals increase, decrease or remain the same:

Subsequent time intervals would decrease. The intervals would still require the rise and fall of the pendulum, however, the distance traveled will be less.

What evidence is there that the time between 'hits' is independent of the amplitude of the swing?

This experiment provides evidence that that hypothesis is false. The length of a pendulum's swing depends on the angle and the lean of the pendulum.