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Sources of Light
Transcript of Sources of Light
There are two types of light:
-Artificial - Light bulbs, Street Lights
-Natural - Sun, Stars, Fire, Candles
Anything that emits light is luminous
Objects that do not emit light are non-luminous
There are different kinds of light sources:
-Bioluminescent Incandescent Sources Fluorescent Sources Phosphorescent Sources A source that emits light made from a chemical reaction. Chemiluminescent Sources Bioluminescent Sources A source which emits visible light after it has been heated to a high temperature. A source that produces light when exposed to light of a specific wave length. A source that uses absorbed energy particles to emit light even after removed from the light source. An animal that emits light because of a chemical reaction inside its body. HOW IT WORKS 1. Phosphorescent source absorbs light energy.
2. Stored energy then later gets released as visible light.
Light Energy can be high energy ultraviolet light or visible light Difference Between... Phosphorescent Sources Fluorescent Sources Particles take longer to emit Particles release light right away Why do Some Animals use Bioluminescence? Lots of animals that live at the bottom of the ocean use bioluminescence because there is no sunlight. Some use it to attract prey.
Examples: Jellyfish and Anglerfish
Fireflies use bioluminescence to attract mates.
Certain types of fungi are also bioluminescent. Incandescent Lights Also Known As...
Incandescent Globes and Incandescent Lamps How it Works Electrical energy goes from the base/socket to the coil/filament. The filament heats up so much that it causes visible light. Energy Transformation Electrical Energy Thermal Energy Visible Light Energy Incandescent Lights in Canada Incandescent lights are going to become illegal in Canada because...
they use to much energy
are more likely to catch on fire Filament/Coil Socket/Base Fluorescent Lights Energy Transformation Ultraviolet Light Energy Energy Absorbed by Particles Visible Light Energy Fluorescent Tubes How it Works 1. Lead-in wires and electrodes give off an electric current which causes the mercury vapour to produce ultraviolet radiation.
2. The ultraviolet radiation is absorbed by the phosphor coating.
3. The coating then starts to glow producing visible light. Electrical Energy Energy Absorbed by Mercury Particles Ultraviolet Light Energy Energy Absorbed by Phosphor Particles Visible Light Energy Disadvantages and Advantages of Fluorescent Lights Expensive to make
Hard to dispose of
Phosphor coating and Mercury vapour are toxic Disadvantages Advantages Fluorescent lights do not use high amounts of thermal energy. Meaning they don't use as much energy. How it Works A chemical reaction gets particles moving which give off a visible light. Chemical Energy Visible Light Energy Glow Sticks Glow sticks have two liquids separated by a barrier.
This barrier breaks when it is bent.
When the barrier is broken the liquids mix causing a chemical reaction that produces visible light. LED Lights These lights don't use a lot of electricity but they can shine very brightly.
LED light fixtures may cost more than fluorescent light fixtures, but they pay themselves off in a year.