Icebergs and Glaciers

There are icebergs and glaciers in both the North and South Poles.

An iceberg is like a mountain of ice in the sea. It looks very, very big, but you can only see a small part of it above the water. Most of it is under the water. Sometimes the water becomes warmer, and the bottom of the iceberg melts. When the top of the iceberg is heavier than the bottom, the iceberg turns upside down and it makes a terrible noise.

Rivers of ice are called glaciers. Glaciers start at the top of a high mountain. They move like rivers but very, very slowly down the mountains. Some glaciers move faster than others. A glacier usually moves between one centimetre and one metre a day.