18.4 Color

This student is looking at many colors on his computer screen. What he is actually seeing, however, are combinations of only three colors of light.

18.4 Color

How does a prism separate white light?

Key Concepts

What determines the color of an object?

What are the primary colors of light?

What are the primary colors of pigments?

18.4 Color

Key Concepts

As white light passes through a prism, shorter wavelengths refract __________ than longer wavelengths, and the colors separate.

After passing the prism, which color of visible light bends the most?

more

violet

18.4 Color

Key Concepts

And which color bends the least?

red

18.4 Color

Sunlight is made up of ______ the colors of the visible spectrum.

The process in which white light separates into colors is called _________________.

A rainbow forms when droplets of __________ in the air act like prisms.

Separating White Light Into Colors all

dispersion

water

18.4 Color

• When light __________ a raindrop, it slows down and refracts.

• Then it reflects off the far inner ______________ of the raindrop.

• It refracts again as it __________ the raindrop, speeds up, and travels back toward the source of the light.

Separating White Light Into Colors enters

surface

leaves

18.4 Color

The Colors of Objects

The color of any object depends on…• what the object is ____________ of• on the color of __________ that strikes the

object.

made

light

and how yourown eyeswork!

18.4 Color

An object’s color is the color of light that reaches your _________ when you look at the object.

• Sunlight contains all the colors of the visible spectrum.

• A red car in sunlight ____________

mostly ________ light.

• Most of the rest of the light is ________________ at the surface of the paint.

The Colors of Objects

eyes

reflectsred

absorbed

18.4 Color

What happens if you change the color of the light shining on an object?

Only the colors that are ________________ can be reflected.

The Colors of Objects

in the light

18.4 Color

What are the primary colors of light?

Primary colors are three specific colors that can be _________________ in varying amounts to create all possible colors.

Mixing Colors of Light

The primary colors of light are _________, ___________, and ___________.

combined

red

green blue

18.4 Color

When any two primary colors combine, a ____________ color is formed.

What secondary color do green and red light produce?

When red, green, and blue light combine, what color results?

Mixing Colors of Light

secondary

yellow

white

18.4 Color

Each secondary color of light is a combination of two primary colors.

The secondary colors of light are ____________, ______________, and _________________.

The Colors of Objects

cyan

yellow

magenta

18.4 Color

If you add a ________________ color to the proper ________________ color, you will get white light.

Two colors of light that combine

to form white light are

___________________ colors

of light.

The Colors of Objects

primary

secondary

complementary

18.4 Color

Mixing Pigments

The primary colors of ______________ are cyan, yellow, and magenta.

A pigment is a material that ______________ some colors of light and ___________ other colors.

Paints, inks, photographs, and dyes get their colors from pigments.

pigment

reflectsabsorb

18.4 Color

Mixing Pigments

When all of the pigments mix together, what color do they produce?

And when magenta and cyan mix?

Cyan and yellow?

Yellow and magenta?

black

blue

green

red

18.4 Color

Assessment Questions

1. A prism separates white light into the visible spectrum because a. longer wavelengths are absorbed more than shorter

wavelengths.

b. shorter wavelengths refract more than longer wavelengths.

c. shorter wavelengths reflect more than longer wavelengths.

d. longer wavelengths experience more interference.

18.4 Color

Assessment Questions

2. The color of an object depends on what the object is made of and on a. the intensity of light that strikes the object.b. the color of light that strikes the object.c. the direction of the light that strikes the object.d. the speed of the light that strikes the object.

18.4 Color

Assessment Questions

3. Which of these colors is one of the primary colors of light? a. green

b. magenta

c. yellow

d. white