1. Baby don’t hurt me, no more.
What is Light?
Baby don’t hurt me, no more.

2. Learning goals
We are learning the different ways light is produced.

3. Sources of Light Incandescence Phosphorescence Chemiluminescence
Triboluminescence
“Lasers”
Electric Discharge
Fluorescence
Bioluminescence
Light Emitting Diodes

4. Incandescence
The production of light from an object that is at a very high temperature.
Hot coals, typical light bulb, sparks, sun, candle

5. Electric Discharge
Producing light by passing electric current through air or gas.
Lightning
Different gases produce different colours
Neon is red orange
Argon is violet to lavender blue
Nitrogen is more pink

6. Phosphorescence
light produced when a substance absorbs light then emits it slowly over time
Generally UV light which is absorbed
Glow in the dark stickers

7. Fluorescence
Light produced when a substance is exposed to electromagnetic radiation (UV radiation)
CFL light bulbs
Rocks/minerals
Bulbs are filled with a small amount of gas, which releases UV light when electricity is applied.
This UV light hits the phosphor coating and causes it to glow and produce light.

8. Chemiluminescence Light produced by a chemical reaction
no increase in temperature
Cool light
Glow sticks!

9. Bioluminescence Chemiluminescence in living organisms
Jellyfish and the firefly!!
Firefly’s glow due to chemical reaction of oxygen and the enzyme luciferase

10. Triboluminescence Light produced by friction specifically in crystals
through the breaking of chemical bonds in the material.
Lifesavers in the dark – does it make a spark!?
Peeling two pieces of duct tape apart

11. Light Emitting Diode (LED)
electroluminescence
a material emits light after passing an electric current through it.
Christmas lights – doesn’t emit heat, doesn’t require a filament, more energy efficient.

12. “Laser”
Laser Video
Light Amplified by Stimulated Emission of Radiation
Electromagnetic waves emitted exactly the same (direction and energy)
Pure in colour, very intense and concentrated into one narrow beam.

13. Learning goals
We are learning the different ways light is produced.