1. 4.1b Types of Light

2. Groups Neala, Harrison, Adriana Destiny, Abbey, Noah Nico, Emma, Zak
Amber, Claire, Cristian
Connor, Josh, Brianna
Blake, Brett, Aidan, Jazmine

3. Group Work
Group member 1: manager - keep everyone on task making sure everyone stays on topic
Group member 2: recorder – make sure every group member has recorded all of the information
Group member 3: time tracker - keep an eye on the time

4. Luminous vs non-luminous
Luminous objects create their own light
Non-Luminous do NOT create their own light
Think of some more in your group

5. Luminous Sources of Light
Natural Sources
Produced without human intervention
Ex. Sun, fireflies
Artificial Sources
Produced and controlled by humans
Ex. Neon signs, flashlight, TV screen

6. Incandescence vs Luminescence

7. Incandescence Light is emitted when a material has been heated
Incandescent light bulbs heat a thin wire filament with electricity
Ex. burning candle, light bulb, burning fuel

8. Luminescence Light given off by an object that has not been heated
Eg. Glow sticks, fluorescent lights

9. T-Chart Comparing the Two Forms of Light
In your group, think of as many examples of incandescence and luminescence that you can

10. Electric Discharge
Light produced when an electric current passes through a gas (which causes the gas to glow) Eg Neon lights
Static electricity is built up between the sky and the ground and then large amounts of electricity travel through the air (gas) and hit the ground. Lighting up the skies

11. Fluorescence
An object absorbs UV light and releases visible light immediately
Fluorescent lights:
Tube is filled with low pressure mercury vapour and is coated with a fluorescent material
mercury atoms emit UV light and transfers it to the fluorescent surface to produce light
Use less energy and produce less heat

12. Chemiluminescence Light produced by a chemical reaction
Gives off no heat
Ex. glow stick

13. Bioluminescence When chemiluminescence occurs in living organisms
Used by many organisms to protect themselves from predators, to lure prey or attract mates
Ex. firefly

14. Triboluminescence
Light produced by friction (scratching, crushing or rubbing) between certain crystals
Ex. rubbing two quartz crystals together, wintergreen mints

15. LED Lights (Light-Emitting Diode)
Light produced as a result of an electric current flowing in semiconductors
Semiconductor: a material that allows an electric current to flow in only one direction
LED’s do not need a filament
Does not produce much heat (wasted energy)
More energy efficient
Used in Christmas lights and traffic lights

16. Pros and Cons
Pick a Form of Light and Brainstorm some pros and cons of using that form of light. Be prepared to present your information
Group member 1: manager - keep everyone on task making sure everyone stays on topic
Group member 2: recorder - record groups ideas
Group member 3: time tracker - keep an eye on the time