Waves on a Slinky

5/21/18 Name: ______Waves on a Slinky

Purpose To investigate properties of mechanical waves

Materials  Slinky® (This slinky is to be treated with care and returned in the same condition in which you received it. For our purposes, this slinky is a delicate piece of scientific equipment, not a toy to be used and abused! Replacing one costs about $12)  long coil  one ounce of common sense

Procedure 1. Stretch the slinky out to a length of approximately 3-4 m (or 10-12 feet). Note that the floor tiles are roughly 1 ft by 1 ft in size. Have one lab partner holding each end. 2. What happens if you quickly move one end rapidly to the left and back again? This effect is called a “disturbance.” What happens to the disturbance? Keep the opposite end still.

3. Repeat until you clearly get the disturbance to reach your lab partner on the other end of the slinky. What moves : does any “matter” move from your to your partner? If not, what does move? Avoid using the term “disturbance” to describe what moves.

4. Observe carefully what happens to the disturbance when it reaches the far end. Record what you see.

5. Disturb the end of slinky toward the other side (to the right) and observe what happens as it moves along the length of the slinky and reaches the far end.

6. Tighten the slinky by pulling in some coils on both sides of the slinky. Disturb one side as in step 2 above. Does the disturbance behave any differently? Record your observations.

7. Are there any other ways that you can disturb one end of the slinky so that the disturbance also travels along the length of the slinky and reaches the far end. Test your idea and record your observations. 5/21/18

The different types of disturbances have been given names: transverse and longitudinal. Determine which name goes with the different disturbances you created.

8. Create two disturbances – one at each end of the slinky – and observe what happens as they move along the length of the slinky, especially noting what happens as they meet. Try different combinations of two disturbances on the same side, opposite sides, transverse/longitudinal.

9. So far the disturbances have been non-repeating – or they have been pulses. Now create a continuous disturbance at one end of the slinky and observe what happens. The disturbance should made at a steady/constant rate. What happens as you increase this rate? How does this affect the motion of the disturbance along the length of the slinky? Repeat this for both longitudinal and transverse disturbances. For the transverse waves, it is best to the long coil. Hold this coil in the air and stretch it between two lab partners. Use the slinky along the floor for the longitudinal waves. Record your observations.

What do you need to specify in order to uniquely describe a disturbance on the slinky? What do you need to specify about the medium (i.e., the slinky or the coil)? What do you need to specify about how the disturbance was created (or what you did)?