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Light, Polarization & Color. The nature of an object’s color. What are examples of color? How can we tell one shade of a color from another? Do objects seem to sometimes change color under different light conditions?. White Light.
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The nature of an object’s color • What are examples of color? • How can we tell one shade of a color from another? • Do objects seem to sometimes change color under different light conditions?
White Light Def: light given off from a source that emits all colors of light at once. Light from a light bulb isn’t just one color, it’s three!
Primary Colors • There are only three primary colors: • Red, Green, and Blue • ALL other colors can be made by mixing these together.
Complimentary Colors • Mixing two primary color together makes one of the complimentary colors: • Red + Green = Yellow • Green + Blue = Cyan • Blue + Red = Magenta
The Color White • If you mix all three primary colors together, they will appear to be the color white. • There are an infinite number of color combinations of Red, Green, and Blue to create different “recipes” of color.
Creating the rainbow… • Smoothing out the colors would make the diagram look something like this.
What’s different about colors? • Each color of light has it’s own specific wavelength.
So…. • If every color has a different wavelength, maybe they behave differently when different colors of light hit the same object. • This is what gives an object it’s color. • (At least, what we think it’s color is)
Everything’s a Mirror • Almost all objects reflect some kinds of light and absorb other kinds. • White objects reflect all colors of light. • Black objects absorb all colors of light. • Absorbing light transfers energy to an object, so black objects heat up more rapidly than white objects.
Everything’s a Mirror • Objects in between only reflect certain kinds of light. • Example:Green leaves reflect green light, but absorb all other colors of the rainbow.
When’s a White shirt not white? • A white tee shirt reflects all colors of light, making it appear white. • If you look at a white shirt under red light, it looks red, because it’s reflecting all the light that’s there (only red), so that’s what you see.
Light Waves • Since light travels in waves, they would look like this from the side: • But this from the front
Light in the real world • Looking at a beam of light from the front, individual waves might look like this:
Polarizing Lens • A polarizing lens only allows light waves lined up in a certain direction to pass through. • A lens looks like the boards on a deck:
Polarizing Lens • Only light that will “fit between the cracks” will pass through the lens. All the other light waves bounce off. • Only these three ray will pass through
Uses of Polarized Light • Polarizing Lenses can be used in the lab in experiments, but practical applications are: • Sunglasses • Window Tint • Video Cameras • Binoculars/ Telescopes • Using Polarizing lenses helps reduce glare and increase visibility in optics applications.
Practice • To practice with these concepts, complete the Section Review on Pg. 474 #1-4.