How is light produced? (How can I explain it to my 4th
First, how light is really produced:
Electrons, and other charged particles, get too much energy. You can almost
say they vibrate too much. To release this extra energy, they release waves
of light. In some ways, it is like vibrating the end of a string or spring.
The extra energy from your hand travels through the string or spring as a
wave. Because it happens at the level of individual particles, you need
quantum physics to get precise. When you heat something, the molecules
vibrate. Now, the vibrating charges in the atoms release waves of energy.
The object glows. A light bulb works the same, but the electricity causes
the heat. Fluorescent bulbs do not even heat up. The energy goes straight
to the electrons.
Now, how to explain it to your brother:
If he knows about electrons and atoms, this should work. If not just do not
mention the atoms. The material gets extra energy and emits waves.
Demonstrate waves on a long narrow spring or a long heavy string. In either
case, let him watch a wave pulse travel along from one end to the other.
Dr. Ken Mellendorf
Illinois Central College
There are many ways to produce light.
Chemically (a fire).
Electrically (a spark).
By heating an object up (an electric stove or a toaster).
Mechanically (strike a flint and steel to produce a spark).
All of these methods involve converting one form of energy (chemical,
electrical, thermal) into another (light).
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Update: June 2012