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 sounds are pretty constant.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sound sounds a bit further apart.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I added index cards underneath thebracket in order to level out the pendulum. It took about 3 index cards to achieve a steady sound.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
1st 45= slower
2nd 45= steady
3rd 45= steady
4th 45= steady
5th 45= steady
6th 45= slower
7th 45= steady
8th 45= steady
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
I would orient the bracket to be parallel to the spine of the book.
** Your report of 8 time intervals between release and the second 'hit': **
T1- .375,.3125,.328125,.328125,.3125,.359375,.34375,.328125
T2- .390625,.328125,.3125,.34375,.34375,.328125,.3125,.3125,.390625
T3- .328125,.359375,.3125,.328125,.375,.328125,.4375,.53125,.4375
T4- .34375,.3125,.328125,.375,.328125,.296875,.53125,.5
T5- .375,.296875,.390625,.265625,.46875,.46875,.3125,.3125
T6- .26,.265625,.21875,.21875,.328125,.34375,.484375,.328125
T7- .375,.328125,.296875,.359375,.375,.296875,.328125,.328125
T8- .21875,.234375,.28125,.328125,.265625,.4375,.203125,.34375
The intervals show that the pendulum is steady.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
T1- .625,.734375,.734375,.1.125
T2- .75,.796875,.996875,.1.125
T3- .734375,.703125,.734375,.765625
T4- .71875,.6875,.765625,.65625
T5- .828125,.9375,.9375,.71875
T6- .640625,.90625,.78125,.953125
T7- .75,.609375,.8125,1.0
T8- .421875,.328125,.8125,.59375
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
8.5cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.63,.75,.73,.71,.82,.64,.75,.42
.10,.04,.+.03,+.03,.11,.27,+.15,.+.09
** Your description of the pendulum's motion from release to the 2d hit: **
The pendulum would be moving at the same velocity throughout if it did not hit. By hitting the bracket, the pendulum slows down.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The pendulum is on an upswing.
&#A full cycle of a free pendulum is from extreme point to equilibrium to opposite extreme point then back to equilibrium and finally back to (almost) the original extreme point.
The pearl pendulum is released from an 'extreme point' and strikes the bracket at its equilibrium point, so it doesn't get to the opposite extreme point.
Thus the period of the pendulum can be divided into four parts. From the steadiness of the rhythm we have good evidence that the motion between 'hits' takes the same time independent of the amplitude of the motion (the rhythm remains constant while the amplitude of the motion decreases). Theoretically each of the four parts of the cycle, as described above, takes the same time. Assuming this to be true, we can speak of the quarter-cycle from an extreme point to equilibrium or from equilibrium to an extreme point.
Through how many quarter-cycles does the pendulum move between release and the second 'hit'?
Through how many quarter-cycles does it move between the second and the fourth 'hit'?
What therefore should be the ratio of the time interval from 2d to 4th 'hit', to the interval from release to the 2d 'hit'?
How does this ratio compare with the results you just reported?
Does this constitute evidence for or against the theoretical hypothesis that the quarter-cycles all require the same time?
Suggested response title: description of motion of pearl pendulum &#
&#Please respond with a copy of this question, a copy of any other part of this document you wish to include, and your response to the question. Indicate your response using the symbols *&##. As your title use the 'response title' suggested above (just copy and paste that title into the Title box of the Submit Work form); if no suggested title was given use your own title.
&#
** 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: **
With each hit the pendulum slows 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 second and fouth hit are faster then the fourth and sixth hit.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
Because the first time interval is before the hit of the bracket.
** 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? **
The longer the pendulum swing, the shorter the lenth away from the center. Yes, the length does have an impact on how far it actually swings.
** **
1 hr.
** **
Your data seem to be OK, but there are a couple of important questions that need additional answers. Please see my notes and respond as indicated.