The New Childrens Encyclopedia

SPECTRUM

SCIENCE

COLOR VISION

Color vision Objects appear

colored to our eyes because their

surfaces reflect some wavelengths of

light but not others. Plants have

chemicals called pigments that color

their fruits and flowers, making

them attractive to the animals that

disperse their pollen and seeds. Most

fruit-eating animals see in color.

Blackberries absorb

all colors of light,

reflecting very little.

Adding color

Televisions produce

hundreds of colors by

mixing red, green, and

blue light in different

quantities. Blending

these three primary

wavelengths to create

new colors is known

as color addition.

Subtracting color

Paints create colors by absorbing

light rather then emitting it.

Mixing the primary paint

colors of magenta, yellow,

and cyan creates new colors

by reducing the range of

wavelengths that are

reflected. This is called

color subraction.

Unstoppable waves

Electromagnetic radiation is everywhere.

Visible light is bouncing off this page,

allowing you to see the words and pictures

printed in different colors. But other kinds

of electromagnetic wave are passing straight

through the pages and through your body

without you even noticing.

 COLOR PRINTING

The microscopic dots used in

color printing come in four

colors, but blend to create the

illusion of thousands more

( p.168–169).

INFRARED (IR) MICROWAVE RADIO WAVES

You see green light

because the ink used here

absorbs all other color

wavelengths.

Warm objects

emit IR radiation.

IR cameras see

heat as white or

red. Cool objects

appear blue.

Microwaves

make certain

molecules move

very fast and

give out lots of

heat energy.

Data, sound,

and pictures can

be transmitted

as radio waves.

Devices such

as telephones,

radio, and TV

sets convert the

waves back into

images and sound

for us to see

and hear.

A tomato absorbs

green and blue light

and reflects red.

Lemons reflect red and

green light, which we

see as yellow.

Green peppers reflect

green light and

absorb red and blue.

Magenta

243

Yellow Cyan

(c) 2012 Dorling Kindersley. All Rights Reserved.(c) 2012 Dorling Kindersley. All Rights Reserved.