Here's a sight you don't see everydaya rock that floats! How can that be?
The key to this mystery is inside the rock.
See how rough the surface is? The insides are just as rough and filled with
many tiny air bubbles. These air bubbles work like balloons, trapping air inside
the rock so it floats on water. But how could this rock have formed in such
© The Children's Museum of Indianapolis, 2000