Mr. Kostecki "Pendulums and Spring Waves Lab"

Pendulums and Spring Waves
Experimenters: Molly Lorenz, Eric Tuvell, Leo Geggis
Purpose: To discover the influencing factors of a pendulum’s time period, and experiment with the natural motion of pendulums and waves.
Materials Used:
• 5 metal washers
• 1.00 m cord
• A long, loosely coiled spring
• Masking tape
• Meterstick
• Paper clip
• Protractor
• Stopwatch
• Support stand
Set Up Drawing:




Experimental Procedure: After the pendulum had been set up with a paperclip on one end of the 1 m cord, with .5 m hanging below the base, and a washer on the end of the paperclip, the washer was lifted to a 20º angle from its resting position. At the same time that the washer was released, the stopwatch was started, and was not stopped until the pendulum had completed ten full swings. This was done three times in order to be able to find the average time for one full swing. Next, the washer was lifted to a 15º angle from its resting position and released as the stopwatch was started. Again, the stopwatch was stopped after ten full swings; this was also done three times. Then the cord was shortened to .75 m, and the washer was again released from a 20º angle as the stopwatch started. The stopwatch was stopped after ten full swings a total of three times. Next, the cord was shortened to .15 m, as the washer was released from a 20º angle and the stopwatch was started. The stopwatch was stopped after ten full swings, this being done three times. In the next part of the experiment, a long, loosely coiled spring was held on the floor at both ends by two people, one at each end. One end of the spring was lifted to 30 cm and put back down on the floor very quickly. After this, in one fluid motion, one end of the spring was moved about 15 cm to the right and then 30 cm to the left. Finally, one end of the spring was quickly pushed forward before being pulled back to its original position.
Analysis:
A. How much time did it take for the pendulum to complete one full swing when it was raised to a 20º angle?
- When raised to a 20º angle, the time it took for the pendulum to compete one full swing on average was 1.43 s.
B. How much time did it take for the pendulum to complete one full swing when it was raised to a 15º angle?
- The time it took for the pendulum to swing on full swing on average when raised to a 15º angle was 1.41 s.
C. Compare the number of seconds of each swing at each position. Which initial angle required the longest time interval to complete one full swing?
- When the pendulum was raised to a 20º angle, it took longer for it to complete one full swing then when it was raised to a 15º angle.
D. How long did it take for each pendulum to complete one full swing?
-The .75 m pendulum’s full swing took 1.72 s. The .15 m pendulum’s full swing took .79 s.
E. Compare your observations for these pendulums with your observations for the .50 m pendulum.
- At .50 m and 20º, the average time for one full swing was 1.43 s. At .50 m and 15º, the average time for one full swing was 1.41 s. At .75 m and 20º, the average time for one full swing was 1.72 s. At .15 m and 20º, the average time for one full swing was .79 s. As you can see, the longest time was at .75 m and 20º, whereas the shortest time was at .15 m and 20º.
(F-H’s necessary trials were not done.)
I. What did you observe when you quickly lifted the spring and set it back down again?
- The amplitude of the wave travelled down the distance of the wave and then returned.
J. What did you observe when you quickly moved one end of the spring about 15 cm to the right and then 30 cm to the left?
- The wave on the right travelled to the other end before returning with the wave reflected on the left side.
K. What did you observe when you quickly pushed the spring forward and brought it back to its original place?
-The compression travelled down to the end of the spring before returning back to the original end.
Conclusion:
The experiments happened in accordance with our studies, behaving as expected. The pendulum with the shortest length had the smallest period time, whereas the opposite is true as well and the waves also followed our notes and preconceived notions.