What is an iceberg?
The iceberg is a famous natural phenomenon- made ‘famous by such films as Titanic
An iceberg is a large piece of freshwater ice is floating freely in open (salt) water. To be an iceberg, the height of the ice must be greater than 5 m (16 ft) above sea level and the thickness must be greater than 30 m (100 ft) and the ice must cover an area of at least 500 square m (5400 sq ft).
Floating pieces of ice smaller than this are termed “bergy-bits”, or smaller again, “growlers”.
How do icebergs form?
Ice on land flows towards the ocean as glaciers and ice sheets. If the ice reaches the sea it often continues to extend as a floating ice shelves or ice tongues. Pieces of ice naturally break off and float away – these are icebergs. When icebergs break off, the process is known as calving.
Do icebergs float?
All icebergs float initially. However, they may become grounded when they enter waters that are too shallow, and they become stuck on the sea floor. They could remain grounded for months to years until they melt enough to float again and continue drifting.
Why do icebergs appear blue, green and stripey?
Icebergs appear blue because ice absorbs more longer wavelength light (yellow/red colour) than shorter wavelength blue light, therefore reflected light is blue.
However, certain parts may otherwise appear green or brown, which is the result of other particles in the ice which changes how the light is reflected. Particles such as algae, rock dust and patches of saltwater can all make the icebergs appear multicoloured.
Where are icebergs found?
Most icebergs are generated from the glaciers and ice shelves of the Antarctic continent and land-masses adjacent to the Arctic Ocean
*** source and more information at British Antarctic Survey
