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Doing The Wave

Demonstrate the movement of a beam of light by making the following types of waves:

Vertical transverse wave

Tie a thin cord or rope to a doorknob or stretch it between two people. Move the rope in a steady up and down pattern. Observe the waves.

Horizontal transverse wave

Now move the rope in a left-to-right motion.

Diagonal transverse wave

This time, move the rope diagonally, reaching your hand approximately from the height of your right shoulder to the height of your left hip.

With each type of wave, observe the following:

Wavelength — the distance from the top of one wave to the top of the next.

Amplitude — the height of each wave crest (the top of the wave) or the depth of each wave trough (the bottom of the wave).

Frequency — the number of wave crests passing a point in one second.

What can you do to change the wavelength, amplitude, or frequency of your waves?

Light travels in a combination of horizontal, vertical, and diagonal waves, each vibrating in a different plane. By separating out one set of waves, you can polarize the light. To simulate polarized light, pass a thin cord or rope through a slit on the back of a slatted chair. Observe what happens when you try to produce a horizontal wave!


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