Light, Mirrors, and Lenses

SECTION 1 Properties of Light 551 Light Travels Through SpaceThere is, however, one important difference between light waves and the water wave ripples on a pond. If the pond dried up and had no water, rip-ples could not form.Waves on a pond need a material—water— in which to travel. The material through which a wave travels is called a medium. ................
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