How It Works

WHITE, BLUE AND BLACK ICE

-

What colour is an iceberg? You might be tempted to say white, but icebergs can come in several different hues. What determines an iceberg’s colour is how its structure and compositio­n interact with light. Most often, an iceberg is blue in colour because pure ice, with few contaminan­ts, absorbs red and yellow light wavelength­s. Shorter wavelength­s, such as blue, are more likely to be reflected off the ice. The surface of many icebergs is what provides them with their striking-white glow. But this is simply a disguising coat. The main body of an iceberg is often covered with tightly packed snow. Because snowflakes reflect all light wavelength­s, the exposed surface of the iceberg is white.

Contrastin­gly, dense marine ice can create black icebergs. Without any cracks, the ice can’t scatter the light that hits it, giving it a dark hue. Although the purest form of iceberg is blue, there are multiple colour variations. When cells from marine life or the iron from rocks is incorporat­ed into the ice, icebergs develop green and yellow hues. And the cloudier the iceberg, the more air space there is within its structure.

 ?? ?? The blue colour of glacial ice is visible where erosion has taken place
The blue colour of glacial ice is visible where erosion has taken place

Newspapers in English

Newspapers from United Kingdom