Geo Mysteries with Rex the Dino Detective The Mystery of the Floating Rock

Here's a sight you don't see everyday—a rock that floats! How can that be?

The key to this mystery is inside the rock.

The mystery rock under a magnifying glass

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 a way?

Sediments deposited on lakebed
Cemented together from pebbles
Magma chamber
Heated deep in the earth
Volcanic eruption
Tossed from a volcano

© The Children's Museum of Indianapolis, 2000

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