What is Ice?

It’s in our homes, our food, and we wouldn’t have ice skating or certain winter sports without it. Whether you’re someone who enjoys a good game of ice hockey, or a lazy holiday maker who likes nothing better than a freezing cold Popsicle on the beach, ice forms part of our everyday lives.

All the frozen water across the surface of the Earth makes up what is known as the cryosphere, which comprises glaciers, lake ice, river ice, sea ice, ice caps and permanently frozen ground (permafrost).

Read on to discover more facts about ice.


How is Ice Formed?

Essentially water frozen into a solid state, ice can be found in our garden ponds, outdoor lakes, rivers and other masses of water – it forms much more easily in fresh water than in salt water.

Freshwater Ice

When the temperature drops below zero, the surface of rivers and streams gradually solidifies into a thin layer of ice which gradually becomes thicker, depending on just how cold it is and how the water is flowing. As water freezes into ice, it becomes less dense and rises to the top – this is how it gains the ability to float. Ice is a good insulator of heat, so water beneath the surface is prevented from further freezing as its cooling is slowed from the top downwards. This is why large bodies of fresh water outside do not become completely solid.

Sea Ice

The Antarctic and Arctic Oceans form the majority of the Earth’s sea ice, which freezes when the temperature drops below zero. It is slower to form than fresh water ice, because sea water has a lower freezing point and its density rises with its decrease in temperature.

Sea ice protects our planet’s climate by keeping the Polar Regions cool. Ice caps prevent the overall temperature of the Earth from overheating by reflecting a large amount of sunlight back into space. Ice from the ocean also provides a habitat for animals such as polar bears, seals and walruses. As such, the study of sea ice is vital to scientists nowadays in order to understand the phenomena behind climate change and global warming.

Did You Know?

Ice formed from the ocean does not raise the sea level when it melts

The provision of fresh water for people around the world comes from glaciers, which store approximately 75% of drinking water consumed globally

Modern day refrigeration has evolved from humans using ice as a preservative for millennia. A 2002 economic census showed that a figure of $600 million was generated by 400 ice production companies in the United States. Its commercial and industrial uses are bigger and more widespread than we could ever imagine.

Icebergs and glaciers come in different colours, because they absorb and reflect shorter and longer wavelengths of light. This is why some appear blue or green; algae living on the top of glaciers can also cause them to appear pink.

There are 16 different types of ice, all classified by their level of density.