1. Introduction to Light

2. Sources of light What sources of light can you think of?
Can you distinguish between “luminous” and “non-luminous” objects? Which is the Sun? The Moon?

3. INCANDESCENCE Light caused by heating up a material lightbulbs
burning fuel

4. LUMINESCENCE Light from unheated objects
There are many different types …

5. fluorescence
Light is emitted by substances when exposed to electromagnetic radiation
More complicated: gas particles emit UV light, which make a phosphor emit light
fluorescent lightbulbs

6. phosphorescence
The ability to store energy from a source of light and then emit it slowly over a long period
Like florescence, but slower
glow-in-the-dark items

7. electric discharge
Light is produced by passing electricity through the air or another gas
lightning
neon signs

8. chemiluminescence
Light produced from a chemical reaction without a rise in temperature
glow sticks
luminol
Bioluminescence is a natural form

9. nuclear fusion
Light is released when hydrogen atoms are pressed together to form helium
the sun!