WHAT A WORLD! force: a push or pull
applied to an object that changes an object’s motion.
ON THE MOVE As the ice piled up, it got heavier. Push your hand down on a bare leg. Push hard! What do you feel? It doesn’t take long before the force on your skin makes it feel a little warm. This warmth is created by the pressure.
pressure: the force made when something pushes against something else.
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Even though ice is cold, the pressure of a stack of ice 2 miles thick made the ice on the bottom just a bit warmer than the ice on top. What happens when ice warms up? It melts! That created a thin layer of water that the glacier could float on.
The glaciers that first started forming near the North and South Poles and at the tops of tall mountains didn’t stay where they started. As the ice piled up, the glaciers pushed out farther and farther at the base. Often, the ice only moved about 3 feet a day, but sometimes it might go as far as 90 feet in one day!
RELEASE THE HOUNDS! Today, as the earth warms up, glaciers are melting. Things that have been frozen inside glaciers for thousands of years are now becoming visible. Rocks, frozen animals, and even human-made tools have been released by melting glaciers. You can see a cave lion that was released from ice here.
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raphic cave lion National Geog
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