How Things Work

328 Pages·1991·35.818 MB·English

by  World Book, Inc

Childcraft
THE HOW AND WHY LIBRARY
VOLUME 12
How
Things
World Book. Inc.
aScottFetzercompany
Chicago London Sydney Toronto
)
1992 Editi—on
Childcraft The How and WhyLibrary
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Acknowledgments
Thepublishersol Childcraft—The Howand WhyLibrary
gratefullyacknowledgethecourtesyofthefollowing
publishers, agencies, and corporationsforpermissionto
usecopyrighted stories, poems, andothermatenal inthisvolume
Full Illustrationacknowledgments appearonpages313-314.
CricketIvlagazine: Thewindskippertoyadaptedfrom Cricket
Magazine
Houghton Mifflin Company: I Met aMan I Could NotSee."from/
Meta Man byJohn Ciardi. published by Houghton fvliftim Company.
Copynght6 1961 byJohnCiardi. Repnnted bypermission
Western Publishing Company, Inc "Hump, the Escalator by
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—
Volume 12
How Things Work
Contents
5 Let's Get Moving
It takes a push or pull to get things moving
or to make them stop.
23 Full of Energy
Sunlight, wind, and burning coal are just a few
of the forms of energy that make things work.
57 Machines Make Easy
It
Not all machines are complicated. Some very
simple machines help people get things done.
99 What's the Matter?
You and ever\1;hing around you are made of tiny
bits of matter called atoms and molecules.
121 Hot and Cold
When heat energj- spreads, things get warmer
or cooler.
161 Seeing the Light
Because light bounces and bends, you can see the
shape, size, and color of things around you.
21 1 Currents and Sparks
Electricity traveling through a wire makes things
hght up, heat up, or move.
239 Hear All About It
Every sound you hear is a vibration made by
something that is moving.
287 More Things That Work
—
From microwave ovens to motion pictures here
is how some familiar things work.
306 Books to Read
308 New Words
312 Illustration Acknowledgments
314 Index
/
^
^
Pushes and
pulls
Back and forth, up and down. Swinging in a
swing is almost like flying. What makes the
swing go up in the air?
Most of the time you do. You "pump" with
your legs and body. Sometimes you can get a
friend to push you. And sometimes you see
the empty swing moving when the wind
—
pushes it. But something you, your friend,
—
or the wind has to give it a push. The swing
can't move by itself.
Anytime a thing moves, something makes
move. Something pushes the way you,
it it,
your friend, or the wind pushes the swing. Or
something pulls it, the way you pull a wagon
or a sled. The push or the pull that makes a
thing move is called a force.