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 gets faster and faster.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The sounds get further and further apart.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I adjusted it with a dime underneath it, but it the sounds got further and further apart, so I used a doubly folded index card under the rear of the bracket.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
0 degrees the sounds are closer and closer together.
45 degrees the sounds are closer and closer together
90 degrees, the sound seems to be at a steady rhythm.
135 degrees, the sound seems to get further and further apart.
180 degrees, the sound seems to get further and further apart.
225 degrees, the sound seems to get further and further apart.
270 degrees, the sound seems to be at a steady rhythm.
315 degrees, the sound seems to be further and further apart.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
I would orient the book perpidicular to either long side.
** Your report of 8 time intervals between release and the second 'hit': **
.484
.500
.469
.453
.438
.469
.453
.469
hese numbers were obtained from the timer program. I clicked the click to time event button as I released the pendulum and clicked it again when the pendulum struck the bracket the second time. The numbers were rounded to the nearest .001
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.563,.625,.609,.656,.703,.672,.797
.531,.656,.640,.625,.797,.766
.563,.656,.718,.703,.703
.563,.609,.609,.609,.609,703,.766
The results were obtained from the timer program. They are the result of clicking the timer button evey 2nd hit.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
9.1cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.555,.637,.644
** Your description of the pendulum's motion from release to the 2d hit: **
The pendulum reaches the half-way point, called equilibrium, of it's cycle when it strikes the bracket.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The motion between the first hit and the second hit is as follows: The pendulum moves from the start point to the bracket, returns to near where the pendulum started and returns to the bracket. This is reperestative of a full cycle of a pendulum. This is different from the starting point to the first hit because it is represents a half-cycle 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 difference between the motion between release and second hit and the motion between second hit and fourth hit is in the smaller distance that the pendulum swings back out from the bracket.
** 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 difference between the motion between the second and fourth hit and the motion between the fourth and sixth hit is the smaller distance that the pendulum swings back out from the bracket.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
We expect that the pendulum will slow down with each hit against the bracket.
If the rhythm remains constant, as appears to be the case (per the setup and your subsequent answers), then the frequency remains the same.
The speed of the pendulum varies during its motion, but its average speed does decrease in proportion to its amplitude, consistent with the constant rhythm.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
We would expect that each subsequent time interval would decrease.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
I would suggest that because the length of the pendulum did not change during the course of the experiment and the fact that no care was taken in how far back the pendulum was pulled, that the data suggests that the length of the pendulum's swing depends only on the length of the pendulum.
** **
About an hour.
** **
Excellent work.
According to your very good description of the motion, considering the constant rhythm, what would you expect to be the ratio of the time interval from release to second 'hit', to the interval between second and fourth 'hit'?
How close is this to the ratio, as you observed it?