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The Slinky or "Snake" Spring


To show the motion of waves and differentiate between transverse and longitudinal waves.


Slinky or a long metal coiled spring.

Procedure and Notes:

Attach one end of the device to a wall and stretch the device out along the classroom floor.

1. Give the device a sharp snap at one end perpendicular to the medium and parallel to the floor to create a transverse wave.

2. Give a series of pulses in succession to create a train of waves.

3. Vary the frequency of the pulses and note the wavelength changes.

4. Give a sharp push in the direction of the medium to create a longitudinal wave.

Summing Up:

1. Note that the individual coils move perpendicular to the device while the pulse, and hence the energy, moves in the direction of the device.

2. Look for repetition in the pulses to observe one wavelength.

3. As the frequency is greater, the wavelength is shorter.

4. In the longitudinal pulse the particles move back and forth in the same direction as the motion of the wave.