The electrons within atoms are the sources
of all light
There are four steps that There are four steps that electrons go through to electrons go through to
produce light.produce light.
Light is formed when...Light is formed when...
3. Fall back down,
1. Electrons gain energy,2. Move up an energy level,4. And release that energy
The tiny packet or bundle of light energy that is released
is called a PhotonPhoton
•LIGHT is made up of a stream (like a wave) of photons
THIS IS WHY WE SAY THIS IS WHY WE SAY LIGHT CONTAINS BOTH LIGHT CONTAINS BOTH PROPERTIES OF WAVES PROPERTIES OF WAVES
ANDAND PARTICLES PARTICLES
1. IncandescentIncandescent: light produced by a thin wire filament; energy flows through and light is given off in the form of light and heat.
2. FluorescentFluorescent: bulb filled w/mercury gas at a low pressure.•Electricity flows through, the electrons collide w/ the gas giving off UV radiation.
•PhosphorsPhosphors coat the bulb absorb the UV radiation and giving off the light.
Fluorescent light without phosphors
3. NeonNeon: bulbs that glow and give off a variety of colors, depending on the type of gas it contains
A beam of coherent light
(a single wavelength)
Used in surgery
LLight ight AAmplification of mplification of SStimulated timulated EEmission of mission of
RRadiationadiation
Def. - When waves vibrate along a single plane (sunglasses)Can you see Can you see the turtle???the turtle???
Gives off it’s Gives off it’s ownown light lightEx. – The Ex. – The sun, light sun, light bulbs, and bulbs, and candles are candles are luminous luminous objectsobjects
Reflects light from another source
Moon
All light can pass through
Some of the light can pass through; Ex. – Wax
Paper
Includes materials that absorb or reflect ALL light so that no light is transmitted through
• White light is actually all colors of the visible spectrum
• Prism: an object (usually a piece of glass) that refractsrefracts white lightwhite light and separates the colors based on their different frequencies
•Additive Colors
•When all three are mixed, white light is produced.
Green
Blue
Red
blue and green are absorbed
Apple Apple appearappears reds red
White light White light = = mixture of mixture of colorscolors
Because….redred light is reflected!!
So what determines the So what determines the color of an object?color of an object?
•Subtractive (used in ink & paint)•When all three are mixed, black is produced.
Yellow
Magenta
Cyan
•Color printers use the same principle.•Look closely; there are only 3 colors of dots. •Magenta, Yellow, and Cyan