Phy 121
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: **
i am missing some lab materials for this experiment, i have only one of the pearls, i have no bolt or no wire to tie the pearl, i will do the best i can with what i have
I put two segments of wire (cut from a plain old lamp cord or extension cord) into each lab kit. It's not impossible that I missed one, but I was very careful about this and don't think I did. The thin wire is, of course, easy to miss when you empty the contents, and I should probably figure out a way to pack it so it doesn't get missed.
** Your description of the rhythm of the pendulum when tilted 'back' **
the sounds get closer together, the sounds got closer together each bounce until the pearl stopped
** Your description of the rhythm of the pendulum when tilted 'forward' **
the rhythm seems to remain about the same, the sounds seemed to be constant until it stopped
** Your description of the process used to keep the rhythm steady and the results you observed: **
i used the large washer from the lab kit to tilt the bracket forward enough until the pearl was barely away from the bracket, the pendulum hit the bracket 10 times
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
first trial base of bracket in center of book parallel to sides of book sounds get closer together
rotate base 45 degrees to right sounds get closer together
now at 90 degrees sounds are constant
45 degrees sounds constant
90 degrees sounds get closer together
45 degrees sounds get closer together
90 sounds get closer together
45 sounds get closer together
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
the bracket would need to be slightly forward so the pearl does not touch the bracket
** Your report of 8 time intervals between release and the second 'hit': **
.367
.336
.320
.438
.367
.320
.422
.313
this is the time interval for the pearl hitting the bracket on the second bounce, timed each second bounce on 8 trials
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.500, .492, .422. .351
.570, .484
.633, .453, .445, .422
.633, .578, .484, .430
time interval on every second bounce, data obtained by timing every second bounce on each trial
** 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: **
.584, .082, .057
** Your description of the pendulum's motion from release to the 2d hit: **
from release point to the point the pearl hits the bracket is half of a cycle
from the 1st 'hit' to the second is half a cycle; there's still the time from drop to 1st 'hit'.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
the motion seems to be the same
there's a difference, and it's apparent in your timings
** 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 cycle between the 2nd and 4th hit is smaller, the pearl does not bounce back as far as the 2nd 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: **
each cycle is getting smaller
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
it should be the longest time interval
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
subsequent time intervals will decrease
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
a shorter pendulum would not swing as far as a longer one
** **
1 hour 45 min
** **
some of the additional time was spent finding lab material that were not in my lab kit as purchased
You have very good data. See my notes. Check out the document at
http://vhcc2.vhcc.edu/dsmith/forms/feedback/ph1_pearl_pendulum_4782.htm ;
however no additional response or revision is necessary.