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' **
As more time progressed after the pearl was released, the bounces were getting closer together.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sounds still seem to get closer together.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I placed the edge of a pair of thin fingernail clippers beneath the edge of the metal piece. The rhythm remained steady until the sound completely died, and it seemed to do so simply as a result of the pendulum loosing momentum.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
I started off with the magnet side of the pendulum facing toward the end of the book (the loose pearl was facing away) under which the dominoes were placed. I lifted the pearl and released it, observing that the sounds stayed constant. I then turned the pendulum to where, when looking straight on at the front of the book, cover upright, the magnet side of the pendulum was facing toward the left (the loose pearl side toward the right). When the pendulum was like this, the sounds were closer together as timeprogressed after releasing the pendulum. I then turned the pendulum where the magnet side was facing away from the top portion of the book (the loose pearl was then facing toward the top of the book). Then, the sounds were closer together too. Finally, I rotated the pendulum to the point where the magnet side was facing right(again, book cover up, upright, in such a way that the loose pearl was hanging to the left). When I released the pearl from this side, the sounds were, again, closer together.
The usual report is that when the stationary pearl hangs 'away from' the pendulum, the sounds get further apart when the pendulum is pulled back and released. When the pendulum is tilted in the opposite direction, so that when stationary the pearl is actually pressing a bit into the bracket, the sounds get closer together. When the pearl hangs so that it is just barely touching the pendulum, when released the rhythm should be constant.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
In order to obtain the most regular beat, one should make the pendulum face in such a way that the magnet side of the pendulum faces the top of the book but in such a way that the loose pearl hangs toward the bottom of the book (i.e., the loose pearl should hang down hill).
** Your report of 8 time intervals between release and the second 'hit': **
.359
.266
.359
.328
.359
.359
.344
.344
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.594, .609
.359, .438
.422, .469
.360, .360
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
3.4 cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.434, .469
** Your description of the pendulum's motion from release to the 2d hit: **
It goes so fast that I can barely register that it has hit and is getting ready to come back for another strike.
Here is a partial description of the motion of a free pendulum. Some details have been left out, but this should provide an example of the sort of description requested:For a free pendulum the pendulum starts at one extreme point, swings back through the equilibrium point (the point at which the pendulum would hang freely) and beyond this point to the opposite extreme point. It then swings back in the opposite direction, passing again through the equilibrium point to the original extreme point. An ideal pendulum will reach the original extreme point; a real pendulum will lose a little energy and won't make it quite back to the original point.This constitutes one complete oscillation of the pendulum.The motion of the pearl pendulum differs in some respects from the above description, and also shares some of the characteristics of this description.How then would you describe the motion of the pearl pendulum from release to the second 'hit'?
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).
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The motion seems to remain constant.
** 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 motion remains constant, seemingly, initially; but, it seems to begin slowing toward the end.
How would you describe the motion from the 2d to the 4th 'hit' and how does it differ from the motion between release and the 2d 'hit'?
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).
** 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: **
None of my releases ever triggered a sixth hit; BUT my guess is that it continues to slow and that the length of the bounce will lessen.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
The pearl has the most momentum at that time point since it has just been released.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
I would suspect that they would incrase (as my data suggests).
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
Even though the pendulum actually drops the longest distance when it is initially released, the interval during this time is shorter, indicating that the pendulum is, in fact, independent of the actual distance of the swing. It seems to depend on the momentum rather than the distance of the swing.
** **
30 minutes
** **
You gave some good answers. However I've asked you to revise your descriptions of the motion of the pendulum, and I've given as an example some of the description of the motion of a free pendulum. Please respond as indicated, and if you then wish to revise some of your subsequent responses, you may do so.
05-26-2007 19:45:20
Coded lines searched and replaced
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' **
As more time progressed after the pearl was released, the bounces were getting closer together.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sounds still seem to get closer together.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I placed the edge of a pair of thin fingernail clippers beneath the edge of the metal piece. The rhythm remained steady until the sound completely died, and it seemed to do so simply as a result of the pendulum loosing momentum.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
I started off with the magnet side of the pendulum facing toward the end of the book (the loose pearl was facing away) under which the dominoes were placed. I lifted the pearl and released it, observing that the sounds stayed constant. I then turned the pendulum to where, when looking straight on at the front of the book, cover upright, the magnet side of the pendulum was facing toward the left (the loose pearl side toward the right). When the pendulum was like this, the sounds were closer together as timeprogressed after releasing the pendulum. I then turned the pendulum where the magnet side was facing away from the top portion of the book (the loose pearl was then facing toward the top of the book). Then, the sounds were closer together too. Finally, I rotated the pendulum to the point where the magnet side was facing right(again, book cover up, upright, in such a way that the loose pearl was hanging to the left). When I released the pearl from this side, the sounds were, again, closer together.
The usual report is that when the stationary pearl hangs 'away from' the pendulum, the sounds get further apart when the pendulum is pulled back and released. When the pendulum is tilted in the opposite direction, so that when stationary the pearl is actually pressing a bit into the bracket, the sounds get closer together. When the pearl hangs so that it is just barely touching the pendulum, when released the rhythm should be constant.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
In order to obtain the most regular beat, one should make the pendulum face in such a way that the magnet side of the pendulum faces the top of the book but in such a way that the loose pearl hangs toward the bottom of the book (i.e., the loose pearl should hang down hill).
** Your report of 8 time intervals between release and the second 'hit': **
.359
.266
.359
.328
.359
.359
.344
.344
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.594, .609
.359, .438
.422, .469
.360, .360
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
3.4 cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.434, .469
** Your description of the pendulum's motion from release to the 2d hit: **
It goes so fast that I can barely register that it has hit and is getting ready to come back for another strike.
Here is a partial description of the motion of a free pendulum. Some details have been left out, but this should provide an example of the sort of description requested:
For a free pendulum the pendulum starts at one extreme point, swings back through the equilibrium point (the point at which the pendulum would hang freely) and beyond this point to the opposite extreme point. It then swings back in the opposite direction, passing again through the equilibrium point to the original extreme point. An ideal pendulum will reach the original extreme point; a real pendulum will lose a little energy and won't make it quite back to the original point.
This constitutes one complete oscillation of the pendulum.
The motion of the pearl pendulum differs in some respects from the above description, and also shares some of the characteristics of this description.
How then would you describe the motion of the pearl pendulum from release to the second 'hit'?
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).
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The motion seems to remain constant.
** 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 motion remains constant, seemingly, initially; but, it seems to begin slowing toward the end.
How would you describe the motion from the 2d to the 4th 'hit' and how does it differ from the motion between release and the 2d 'hit'?
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).
** 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: **
None of my releases ever triggered a sixth hit; BUT my guess is that it continues to slow and that the length of the bounce will lessen.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
The pearl has the most momentum at that time point since it has just been released.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
I would suspect that they would incrase (as my data suggests).
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
Even though the pendulum actually drops the longest distance when it is initially released, the interval during this time is shorter, indicating that the pendulum is, in fact, independent of the actual distance of the swing. It seems to depend on the momentum rather than the distance of the swing.
** **
30 minutes
** **
You gave some good answers. However I've asked you to revise your descriptions of the motion of the pendulum, and I've given as an example some of the description of the motion of a free pendulum. Please respond as indicated, and if you then wish to revise some of your subsequent responses, you may do so.