How is light produced?

•Luminous: objects that emit their own light i.e. the sun, a flashlight turned on

•Nonluminous: objects that do not emit light i.e a flashlight switched off

Luminous Sources of Light

•Light from Incandescence: the process of emitting light because of a high temperature i.e. light bulb, fire

•electrical charges move through the filament in the bulb to make it heat up and glow

As an object gets hotter and hotter it will eventually produce light (can be different colours depending on temp.)

Red Orange Yellow White Bluish white

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Light from Incandescence

•Light from Electrical Discharge: the process of emitting light because of electricity passing through a gas i.e. lightning, neon signs

•Light from Phosphorescence: an object that can emit light for a period of time after light has been shined on it.

•i.e. the hands and numbers of a watch, some glow in the dark toys

•Light from Fluorescence: the process of emitting light while receiving energy from a different source i.e. fluorescent light bulbs

•Light from Chemiluminescence: the process of changing chemical energy into light energy with little change in temperature i.e. glow sticks

•Light from Bioluminescence: a chemical reaction that takes place inside a living organism that makes them emit light i.e. bacteria, fungi, fireflies etc

•Almost 70% of deep-sea fish are bioluminescent!