Image Courtesy of Antarctic Cooperative Research Centreand Australian Antarctic Division

The Shackleton story is about the ingenuity and resiliency of people facing a dangerous situation in an extreme environment. Sea ice is a big part of that story. Sea ice blocked the way as the Endurance tried to sail south from South Georgia Island. Sea ice imprisoned and then crushed the ship. Sea ice became the platform on which the men pitched their tents, housed their dogs, caught their food, cooked their meals, and dragged their sleds and boats. Sea ice was a formidable foe as the men tried to reach land. The sea ice was dangerous because it was so unpredictable. It could be tilted, jagged, pitted, slushy, fragile, or unstable.

Sea ice forms when salt water freezes. It is different from icebergs and glaciers. Icebergs and glaciers form from fallen snow or from water that evaporates from the ocean. Icebergs and glaciers have no salt in them. Sea ice, because it is frozen ocean water, is salty.

Sea ice can be found in both the Arctic and the Antarctic. The amount of sea ice changes from season to season and also from year to year. In general, sea ice grows during the winter season, when temperatures decrease and more of the ocean freezes, then shrinks during the summer season, when temperatures rise and most of it melts.

Today, scientists study Antarctic sea ice very carefully. We now know that sea ice covers a huge area of ocean each winter. We also know that the freezing and melting of such a huge amount of ice each year influence local climate and weather. Information about how sea ice changes seasonally and from year to year can be fed into computer models to help us predict future climate conditions. You will learn more about scientists' climate studies later on.

Goals

1. You will use satellite images to look at the expanse of sea ice around Antarctica in both summer and winter. You will then calculate how much area the sea ice covers.
2. You will learn about the relationship between Earth's seasons, the height of the Sun, and the concentration of energy on Earth's surface.