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:

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

the rhythm gets faster and closer together.

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

pearl strikes fewer times with a slowing rhythm, getting further apart.

Your description of the process used to keep the rhythm steady and the results you observed:

paper was placed under the bracket to make the pearl barely tough. the rhythm was steady hitting the bracket a total of 24 times

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

after placing dominos under the text book (face up), i placed the bracket on the textbook. after swinging the pearl severl times on each 45 degree angle of the book, i came up with the results.

the pearl stayed steady on each of the 45 degree angles of the book.

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

when the bracket was level with the pearly slightly touching the bracket, produced the most steady result

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

1 141.2031 141.2031

2 141.4531 .25

3 141.7656 .313

4 142.0156 .25

5 142.3125 .297

6 142.5469 .234

7 142.8438 .297

8 143.1563 .313

9 143.4375 .281

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

.594, .641, .656, .641, .594, .5625, .610, .594, .610, .625

.531, .594, .656, .610, .641, .594, .563, .531

.5, .484, .594, .610, .578, .688, .625, .594, .703

.625, .656, .625, .625, .594, .656, .563, .641

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

8 cm 1 mm or 81 mm

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

.5625, .59375, .63275

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

the motion was faily consistant

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

pearl slows slightly

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:

pearl swings slower even more slightly

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:

motion between 2nd and 4th hit is faster then the 4th and 6th hit

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

because it has just been released from a certain distance, the pendulum is swinging at a faster rate, therefore the pearl will hit more often at the beginning

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

time intervals will increase showing that the pendulum is swinging at a slower rate and the pearl is hitting less often

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

the length of the pendulum is not the only factor that affects the swing, the angle at which the bracket is leaning forwards or backwards has a great affect on whether the pearl will hit more or less frequently as opposed to being straight up

Your data look good.

After the due date we will be discussing this experiment further via an online forum.