Light When you throw a stone into a still pond, you create a wave on the
surface that spreads out, forming a disturbance in the form of a
growing ring.
Light has features that are like this. It is a wave, but what is waving is not
the surface of the pond, but something having to do with electricity.
Light is a radio wave, but the frequency is 500,000,000
Megahertz instead of the 100 Megahertz of an FM radio station
(Megahertz already means that something happens 1,000,000 times
per second, so the oscillations of light are really fast!).
Light can also described in terms of the length of the waves
-- about 1/40,000 of an inch for visible light -- which is so small
that we usually do not notice that it has any size at all.
The waves also travel very fast: 186,000 miles per second: "around the
world 7 times" as fast as you can say it!
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