Page 116 - DK Children's Encyclopedia

Friction SEE ALSO

▸ ▸ Forces p.108
▸ ▸ Water
Friction is a force that slows down moving things by pulling pp.120–121
against the direction of their movement. It is created ▸ ▸ Gravity p.125
between two surfaces as they move past each other. ▸ ▸ Materials p.157

Different surfaces produce different amounts of friction. ▸ ▸ Temperature
p.252

Grip or slip?
Rough surfaces grip better because Producing heat
they create more friction than smooth If we rub our hands
together there is friction
surfaces. Smooth surfaces slip past between them. They start
each other because they create less to get warm because
friction than rough surfaces. friction produces heat.

Rubber sole
Snow boots have rough
rubber soles that grip,
so that the climber’s
feet don’t slip.

Rubber grip on
snow boots

Icy surface
Lots of friction
The icy surface and the
sole of the boot have lots Smooth bottom
of friction between them. of the ski

Skis
Smooth skis slide over
an icy surface very
Icy surface easily. They are made
Not much friction of many different
materials, including
The snow and the ski have wood and plastic.
little friction between them
and the ski slides easily.

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