PRODUCING LIGHT

Incandescent Lights Heating a piece of metal until it glows Thin wire called a filament More than 80 percent of the energy in

this light is produced as heat

Fluorescent Lights Filled with a gas at low pressure Inside of bulb is coated with

photophosphors that emit visible light when the absorb ultraviolet radiation.

Contains electrodes at each end Very efficient

Neon Lights Vivid glowing colors Glass tube filled with different gases to

make different colors Molecules collide to make the light

Sodium Vapor Lights Tube that contains neon gas and argon

gas and a small amount of sodium metal Use in street lights Emits a yellow glow

Tungsten-Halogen lights Tungsten filament inside quartz bulb or

tube and a gas Filament becomes hotter than the

incandescent light because of the gas

Lasers Number of light waves are emitted at the

same time. Each atom must give the same energy Light waves are sent from the atoms Helium laser--red light

Laser light is coherent all traveling the same wavelength

Using Lasers CD players Surgincal tools Surveyors for buildings Measure the moons orbit Communications

In Medicine Used to remove cataracts, reshape the

cornea and repair the retina Laser seals off blood vessels as it cuts

and reduces bleeding and scars

CD Player Lasers are used to burn the holes into the

CD so that it can play. Laser is used to read the CD and play

what is on it.