More Fun with Waves Lab

Same principles as my previous Waves Lab.

Part 3: Interference of Transverse Waves

1) If the two wave pulses are on the same side of the spring, what happens when the two waves meet in the middle of the spring?  Describe in words and drawings.

The two waves hit each other in the center of the spring, and then seem to pass through each other and continue without much of a delay.  However, the waves appear to bounce off each other slightly at contact, but then continue on their path.

2) If the two wave pulses are on opposite sides of the spring, describe in words and drawings what happens when they meet in the middle of the spring.

Not much of a change from step 1.  The waves hit in the middle and have a very slight pause and the wave amplitude shifts for a bit, but then returns back to the prior state and continues to the end of the spring.

Part 4: Periodic Transverse Waves

3) Vary the rate at which you vibrate your hand; in other words, try shaking your hand back and forth slowly and then more quickly. How does the length of the waves that you produce depend on how fast you are vibrating your hand?  Describe.

The rate of the vibration does in fact affect the length of the waves.  Josh and I did three different speeds of vibrations to see how it affected the wave lengths.

- When we shook the spring slowly, only one-two long waves appeared before hitting the end of the spring.

- When we shook the spring at average or "medium" speed, four-five waves showed total before hitting the end of the spring.

- When we shook the spring quickly and rapidly, as much as eight small waves appeared along the spring before reaching the end. 

So the speed that we vibrate our hand definitely has an effect on the length of waves.  The faster the vibration, the shorter the waves.

4) Does the speed at which the wave travels down the spring depend on how fast you are vibrating your hand?

The speed that you vibrate your hand should not affect the speed of the wave.  We could test this by seeing how long it would take for a wave to travel a complete period (to there and back).  So we did a slow vibration and recorded some times, then did the same for quick vibrations.

Slow vibration - 

1st Trial - 1.83 sec

2nd Trial - 1.89 sec

3rd Trial - 1.86 sec

Average - 1.86 sec

Quick vibration -

1st Trial -1.78 sec

2nd Trial - 1.92 sec

3rd Trial - 1.85 sec

Average - 1.85 sec

As you can see, the average times for the completion of a period were almost equivalent.  Therefore, the speed of the vibration doesn't affect the speed of the wave.

Part 5: Standing Waves

1) Record the time it takes to complete ten cycles.  Calculate the frequency, period, wavelength, and speed of the wave.

One large wave -

1st Trial - 13.78 sec

2nd Trial - 13.63 sec

3rd Trial - 17.36 sec

Average - 14.95 sec

Average speed - 

(12x10)/14.95 = 8.03 m/s

Period - 

14.95/10 = 1.495 seconds

Frequency - 

1/1.495 = .6689 Hz

Wave Length

Six meters (one large wave)

2) Change the rate of your vibrations until you can see two "humps" in the wave.

Record the time it takes for the wave to complete ten cycles.  Calculate the frequency, period, wavelength, and speed of the wave.

Two waves (humps): 

1st Trial - 9.08 sec

2nd Trial - 9.60 sec

3rd Trial - 9.44 sec

Average - 9.37 sec

Period:

9.37/10 = .937 sec

Frequency:

1/.937 = 1.067 Hz

Wave Length:

About three meters

3) Three humps

Record the time it takes for the wave to complete ten cycles. Calculate the frequency, period, wavelength, and speed of the wave.

Three waves (humps):

1st Trial: 5.35 sec

2nd Trial: 6.47 sec

3rd Trial: 5.76 sec

Average: 5.89 sec

Period:

5.89/10 = .589 sec

Frequency:

1/ .589 = 1.7 Hz

Wave length:

Around two meters