4. WHERE DOES LIGHT COME
FROM?
Most light comes from things that give off
heat. Natural light comes from the Sun, other
stars, and certain animals that glow in the
dark. Artificial light comes from things that
people make. The flame of a candle gives off
artificial light. Electric light bulbs give off
artificial light.
5. HOW LIGHT TRAVELS
Light travels at very high speed. It travels
through space faster than anything we know
of. You can tell that light travels faster than
sound when you see lightning. You’ll notice
that you usually have to wait a few seconds
after the lightning bolt to hear thunder.
Thunder is the sound that lightning makes.
6. HOW LIGHT TRAVELS
The speed of light through empty space is
about 186,000 miles per second (about
300,000 kilometers per second).
Astronomers talk about vast distances in
space as light-years. A light-year is how far a
beam of light can travel in one year, or about
5.8 trillion miles (about 9.5 trillion kilometers).