pearl pendulum

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 rhythm remains constant.

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

The rhythm remains constant.

If the pendulum is tilted 'back' the time between strikes will increase; the rhythm will slow.

If the pendulum is tilted 'forward' the time between strikes will decrease; the rhythm will get faster.

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

I placed the pendulum on a level table. The rhythm was steady and hit the bracket about 11 times.

** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **

For the initial position, the pendulum was placed in the 12 o'clock position; the base was parallel to the sides of the book and the bob and bracket were facing the top of the book with the dominoes, that is upward. After each trial, the pendulum was rotated 45 degrees counterclockwise. The results for the eight trials are listed below.

1.The sounds remained constant, neither further apart nor closer together.

2.The sounds remained constant, neither further apart nor closer together.

3.The sounds remained constant, neither further apart nor closer together.

4.The sounds remained constant, neither further apart nor closer together.

5.The sounds remained constant, neither further apart nor closer together.

6.The sounds remained constant, neither further apart nor closer together.

7.The sounds remained constant, neither further apart nor closer together.

8.The sounds remained constant, neither further apart nor closer together.

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

Any of the orientations should provide a regular beat. I placed the pendulum in the three o'clock position (90 degrees from the initial position).

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

1 .469

2 .453

3 .406

4 .469

5 .422

6 .453

7 .391

8 .453

Every second time the bob struck the bracket, I recorded the time. The numbers indicate reasonable consistency in my ability repeat each successive trial in the same manner as the previous.

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

1 .328, .547, .563, .578

2 .344, .609, .547, .578

3 .406, .578, .563, .578

4 .375, .625, .531, .547

I timed every second hit of the bob against the bracket until the pendulum stopped swinging. The numbers indicate a constant rhythm, a steady beat. The time from release to the second hit is not a full period, so these times are shorter.

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

80mm

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

.36, .59, .55

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

The motion of the pendulum between release and the first 'hit' is the equivalent of one fourth of the period of the pendulum.

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

The motion of the pendulum between the first 'hit' and the second 'hit' is the equivalent of one half of the period of the pendulum.

** 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 of the pendulum between release and the second 'hit' is the equivalent of three quarters of a period and differs from the motion between the second 'hit' and the fourth 'hit' in that they represent a full period.

** 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: **

There is no differece because they both represent a full cycle of the pendulum.

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

The first time interval should be shorter than the subsequent time intervals because it is not a complete cycle.

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

Stay the same.

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

Each time the bob strikes the bracket the amplitude changes but the rhythm remains constant. This indicates that the period is determined by the length of the pendulum.

** **

2.5 hours

** **

&#

Good work. See my notes and let me know if you have questions. &#