That is a good physics question! Yes, gravity
does affect they way balls bounce. Gravity pulls
the ball toward the ground, slowing the ball down
so that each bounce is shorter and shorter, until
eventually the ball stops bouncing. The force of
the ball hitting the hard ground puts an equal
force back onto the ball, causing it to bounce up.
This happens because balls are made out of an
elastic material like rubber, which means they can
be dented or stretched and then return to their
normal shape (think of what happens when you
squeeze a balloon). If the ball was made of
something softer like silly putty, it would just
be squashed on the ground and wouldn't bounce. If
the ball was made of something harder like glass,
it would hit the ground and break.
Try bouncing balls with different stiffness
(like a fully-inflated soccer ball compared to a
half-inflated soccer ball, or a tennis ball
compared to a baseball) and see what happens.
Also, the type of surface you bounce the ball on
will affect how high the ball bounces - try
bouncing a ball on hard concrete and then on soft
grass. Can you guess what would happen?
Note from a reader:
In reference to Answer #1 above, "If the ball
was made of something softer like silly putty, it
would just be squashed on the ground and wouldn't
As every child knows, Silly Putty bounces!
It's one of the unique features of this material.
Probably better to go with clay or Play-dough
as an example.
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