pearl pendulum

Your work on pearl pendulum 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:

Hello Prof. Smith,

Here is my Pearl Pendulum assignment.

Tanya

Your description of the rhythm of the pendulum when tilted 'back'

After I tilted the bracket back and pulled the pearl, it struck the bracket with very rapid sounds. The sounds got closer together. The time intervals between the last several sounds were much shorter than between the first couple.

The rhythm got faster and faster by the end of the sounds.

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

After I tilted the bracket forward a bit and I pulled the pearl off, the pearl struck the bracket less and less frequently with each bounce. The sounds got further apart and the rhythm got slower.

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

I placed some paper under the bracket to make it tilt forward a bit. After the pearl hung straight down, so it just barely touched the bracket, I pulled it off. The pearl struck the bracket about 9-10 times.

Your description of what happened on the tilted surface, rotating the system 45 degrees at a time:

Step 1: Put 4 dominos under each corner of an upward turned closed book.

Step 2: Place the bracket on the middle of the book, so it is parallel to sides of the book.

Step 3: Pull the pearl off and listen to the sounds. The number of the sounds is approximately 10.

Step 4: Turn the bracket 45 degrees counterclockwise and repeat it again. The number decreased from 10 to approximately 7 strokes.

Step 5: Turn the bracket 45 degrees counterclockwise, so it is opposite from the first position and repeat it again. The number of sounds is 10.

Step 6: Turn the bracket again 45 degrees and repeat. The number of strokes is 12.

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

I will put the bracket parallel to the side of my table. I will do it this way because when the bracket was in positions in steps 3 and 5 the book was parallel the side of the table, it had an equal number of beats.

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

1 439.8438 439.844

2 440.0938 .25

3 440.3281 .234

4 440.5625 .234

5 440.7969 .234

6 441 .203

7 441.1719 .172

8 441.3594 .188

1 533.6406 533.641

2 533.8594 .219

3 534.0781 .219

4 534.2813 .203

5 534.4844 .203

6 534.6563 .172

7 534.8281 .172

8 535.0156 .188

1 2134.156 2134.156

2 2134.375 .219

3 2134.609 .234

4 2134.813 .203

5 2134.969 .156

6 2135.141 .172

7 2135.297 .156

8 2135.516 .219

1 2171.047 2171.047

2 2171.234 .188

3 2171.422 .188

4 2171.578 .156

5 2171.75 .172

6 2171.922 .172

7 2172.094 .172

8 2172.25 .156

1 2224.438 2224.438

2 2224.672 .234

3 2224.891 .219

4 2225.063 .172

5 2225.234 .172

6 2225.391 .156

7 2225.563 .172

8 2225.734 .172

1 2259.938 2259.938

2 2260.188 .25

3 2260.375 .189

4 2260.578 .203

5 2260.75 .172

6 2260.938 .188

7 2261.109 .172

8 2261.266 .156

1 2314.125 2314.125

2 2314.313 .188

3 2314.469 .156

4 2314.609 .141

5 2314.719 .109

6 2314.844 .125

7 2314.984 .141

8 2315.109 .125

1 2347.234 2347.234

2 2347.469 .234

3 2347.656 .188

4 2347.813 .156

5 2347.969 .156

6 2348.125 .156

7 2348.281 .156

8 2348.422 .141

1 2369.625 2369.625

2 2370.031 .406

3 2370.234 .203

4 2370.391 .156

5 2370.563 .172

6 2370.719 .156

7 2370.859 .141

8 2370.984 .125

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

2.203, 1.813, 1.766, 1.688, 1.531, 1.219, 0.844, 0.734, 0.344, 0.281

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

6.3 sm

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

0.39, 0.125, 0.469

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

This is the largest distance, therefore the motion is the longest.

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

The distance is shorter that is why the motion is much quicker

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 time interval is different. The motion between release and the second hit is very long. The motion between 2 and 4 is shorter because the distance is decreased.

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 motion between 2 and 4 is longer and between 4 and 6 is shorter.

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

If we would tilt the bracket a little bit forward.

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

We expect subsequent time intervals to decrease because the bracket was staying on the almost perfect level surface.

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

The evidence of this fact is that when we measured the time intervals between each stroke of the pearl, we've gotten different numbers. The first stroke had the largest time interval when the bracket was staying on a almost perfect surface.