2.2 Visible Light and Color7.6.e Students know that white light is a mixture of many wavelengths (colors) and that the retinal cells react differently to different wavelengths7.6.f Students know light can be reflected, refracted, transmitted, and absorbed by matter.

Visible Light• Light can be either

▫A primary source of light-emits its own light OR

▫A secondary source of light- reflects light from a primary source

• Key concept: “When light strikes an object, the light can be reflected, transmitted, or absorbed.”

When Light Strikes an Object

•When light strikes an object, the light can be reflected, transmitted, or absorbed.

Transparent

•It transmits most of the light that strikes it•When light hits it the particles absorb but then reemit until the light finally passes through to the other side•If there are any imperfections, in the material, they can scatter the light- similar to how translucent material reacts

Transparent Squid

Translucent

•Scatters light as it passes through•You can usually see something behind it but the details are blurred•Examples: wax paper and frosted glass

Translucent Reed Frog

Opaque•Reflects or absorbs all of the light•Cannot see through it because light cannot pass through it

Opaque Idocrase

The Color of Objects•Key Concept: The color of an opaque

object is the color of the light it reflects.

Combining Colors

Primary Colors3 colors that can combine to

make any other color

Secondary ColorsProduced when 2 primary colors

combine in equal amounts

Red and Yellow combine

Blue and Yellow combine

Red and Blue combine

Combining Colors- LightKey Concept: When combined in equal amounts, the

three primary colors of light produce white light.

Primary colors of light: red, green, and blue

Secondary colors of light: when 2 colors combine in equal amounts

Complementary colors- any 2 colors that combined and create white light

If you combine a primary color and secondary color of light you get white

Combining Colors- Pigments•The primary colors of pigments

combine in equal amounts to form black.Primary colors of

pigment are magenta, cyan, and yellow

Pigments- colored substance that are used to color other materials

Pigments absorb some light and reflect others Key concept-

As pigments are added together, fewer colors of light are reflected and more and more are absorbed.

If you combine any 2 primary pigments you get a secondary color- red, green, and blue