1. optics Light and Applications of Optics

2. Producing Light (p.278) Luminous objects, such as our Sun, produce their own light Non-luminous objects, such as the Moon, do not produce their own light Most objects are non-luminous There are many different ways light can be produced from luminous sources

3. 3min Incandescence 1min how it's made 5 min The production of light from high heat E.g. an incandescent bulb (tungsten filament) or a candle Only 5-10% efficient!!

4. Electric Discharge The production of light by passing an electric current through a gas Eg. a street lamp or neon sign 8min 4min

5. Phosphorescence "glow in the dark" The process of producing light by the absorption of UV radiation resulting in the emission of visible light over an extended period of time E.g. glow-in-the-dark toys 22 sec

6. Fluorescence The immediate emission of visible light as result of absorption of UV radiation Eg. Fluorescent bulbs (tube or compact) A fluorescent bulb uses both electric discharge and fluorescence

7. Fluorescence The bulb is filled with mercury vapour and coated with a fluorescent material (phosphor) The electricity causes the mercury atoms to emit UV radiation, which then strikes the fluorescent coating which emits visible light 1.5 min 8min

8. Chemiluminescence The production of light as a results of chemical reaction with little to no heat produced Eg. Glowstick or luminol 3min elephant toothpaste 1min

9. Bioluminescence The production of light in living organisms as a result of a chemical reaction with little or no heat produced Eg. Fireflies, some types of bacteria, fungi, marine invertebrates, and fish 2min 13 sec 3min

10. The production of light from friction as a result of scratching, crushing, or rubbing certain crystals Eg. Rubbing two sugar cubes together or biting Wint-O-Green lifesavers http://www.youtube.com/wa tch?v=6Q9s13HHGsI Triboluminescence

11. Light-emitting diodes (LED) are electronic devices in which light is produced as a result of an electric current flowing through a semiconductor Are extremely energy efficient Eg. Christmas lights LED’s

12. Read pg. 470-476 in your textbook Do Q# 2,4-6, 8-11 on pg. 476 Your Turn