An iceberg is a piece of glacier that has broken off, at the edge, which touches the sea. These huge pieces of ice lie submerged under the surface of the water.
Icebergs vary greatly in size. Smaller ones measuring from 5 to 10 metres across are called growlers. But the most common ones are those which measure over 100 metres. There are some giant icebergs also, which measure as much as 1,000 metres.
An iceberg is only eight-ninths as heavy as sea water, so that one-ninth of it sticks out above sea level and the eight-ninths are below. Some of them can weight as much as 180,000,000 tonnes. Due to the above two facts, they do not drift with the winds. Rather, they follow the ocean currents. When they reach the warmer latitudes, they melt. Those that have not, pose danger to ships.
Below Iceberg info from Wikipedia (Read More):-
An iceberg is a large piece of freshwater ice that has broken off from a snow-formed glacier or ice shelf and is floating in open water.[1] It may subsequently become frozen into pack ice. Alternatively, it may come to rest on the seabed in shallower water, causing ice scour (also known as ice gouging) or becoming an ice island.
http://en.wikipedia.org/wiki/Iceberg
