Slinky Lab

Purpose: To provide a concrete model of wave motion

Note** DO NOT RELEASE THE SPRING WHEN IT IS STRETCHED OR IT WILL TANGLE!!!

Procedure: Part I1. With one person at each end, stretch the spring to about three meters on the floor. Record your measurement in the data table.2. While one person holds one end very still, the person at the other end can send a wave along the spring by gathering about 5 coils in your free hand and suddenly releasing them. Be sure to hold the end of the spring after releasing the coils.3. Record the time it takes for the wave to travel the distance.4. Repeat two more times using 10 coils and 15 coils. Calculate the speed of the waves.

a) Name the type of wave you have created ________________

b) Draw this wave labeling its parts.

c) Is the speed of the waves constant?

d) How does the speed of a small wave (a few coils) compare to the speed of

a large wave (many coils)?

# of coils Spring length Wave time Wave SpeedWave 1Wave 2Wave 3

Part II1. With one person on each end, stretch the spring to about three meters on the floor. Record your measurement in the table. 2. While one person holds one end very still, the person at the other end can send a wave along the spring by moving the end sharply to one side and back. 3. Record the time it takes for the wave to travel the distance.

4. Repeat two more times and calculate the speed of the waves.a) Name the type of wave you have created ________________

b) Draw this wave labeling its parts.

c) Is the speed of the waves constant?

Spring length Wave time Wave speed(d / t)

Wave 1Wave 2Wave 3

Average Speed:

Part III1. With the slinky still at three meters, create a wave with several wavelengths. You make one wavelength when your hand moves left, right, and left again. Count the number of wavelengths that you generate in 10 s. Record this measurement in the table.2. Repeat step 1 two more times. Each time, create a wave with a different wavelength by shaking the spring faster or slower.3. Calculate the frequency of the waves by using the following formula:

f = # waves / time4. Calculate the wavelength of each wave by using the following formula:

λ = wave speed / frequency (For wave speed, use the average speed of the

three waves in part II)

Wave Count Time Frequency WavelengthWave 1Wave 2Wave 3

Part IV1. With one person on each end, stretch the spring to about three meters. 2. One person holds the spring completely still. The other begins moving the spring slowly from side to side.3. Gradually increase the frequency of the motion until you observe one standing wave pattern. Count how many waves you have during 10 s.4. Continue increasing the frequency until you observe 2 standing waves. Count how many waves you have during 10 s.5. Continue increasing the frequency until you observe 4 standing waves. Count how many waves you have during 10 s.

# of Waves Time Frequency1 standing wave2 standing waves4 standing waves

Questions: 1. What is the difference between transverse and longitudinal waves?

2. What variables affect the speed of a wave along a spring?

3. Does the student holding the opposite end of the spring feel the effect of a transverse and/or longitudinal wave?

4. Does this demonstrate that these waves have energy?

5. What is the net effect of the waves on the spring? (In other words, after the wave has traveled across the spring, is the spring in a new position or the same position as it started at?)

6. How did the wavelength of the waves you created depend on the frequency of the waves?

7. In creating different numbers of standing waves, is there a relationship between the frequency and the number of standing waves? If yes, what is the relationship? If no, why not?