Learn more physics!
How can you see light travel?
- Tony Tse (age 10)
E. R. Taylor, S.F., CA, United States
An important point in being able to see something is that light it has
to bounce off of something before going to our eye. Think of a regular
light bulb. It sends out a lot of light in all directions when it is
turned on. If you look right into the light (don't so this because it
hurts your eyes), it is bright because a lot of light is going straight
into our eyes. But when you look elsewhere, you don't see the stream of
light going everywhere. In order for us to see that light, it has to
bounce off something first, that's how it get's a specific color. If
you look at your hand, you are seeing the light that is bouncing off
your hand and going into your eyes.
All this is possible because light moves all over the place and
bounces around. If it didn't move, we wouldn't be able to see anything.
In case you're curious, light moves pretty fast. It moves at about
1 billion kilometers per hour or about 670 million miles an hour. To
make it easier to picture this, in less than 5 seconds, light can
travel from the Earth to the moon and back again!
(republished on 07/29/06)
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