An igloo is a shelter made from blocks of snow and ice. It is constructed by Inuit tribes when out on hunting trips in winter and is not intended as a permanent residence. It is common among tribes in Canada's Central Arctic and in Greenland. In summer, when snow is less thick, building an igloo is not possible.
Building an Igloo
Blocks of hard-packed snow are cut and placed in the shape of a circle. The first layer is shaped so that a spiral can be made which curves inward towards the top. The last block to be fitted at the top is carefully shaped so that it locks the whole structure together. Any gaps in the walls are packed with loose snow. An entrance tunnel is constructed which further protects the inside from the winds.
Temperature Inside an Igloo
Snow is a good insulator, and the igloo shelters the inhabitants from the wind which can reduce the outside temperature considerably. The igloo traps the body heat, and it has been estimated that a single oil lamp combined with body heat can raise the temperature inside an igloo by 4.44 degrees C above that of the outside air. The heat inside melts a layer of the snow which refreezes overnight and seals any gaps in the walls.
Living in an Igloo
The snow blocks to make the igloo are cut from inside its shape. Half is left untouched though, and this raised part is the sleeping area. This is the warmest part of the igloo because warm air rises. The other half of the igloo is used for cooking and eating. An oil lamp gives light and heat for cooking and warmth. A window to let light in can be cut from one of the snow blocks and a block of ice inserted.
Cooking in an Igloo
Cooking is done over a seal oil-lamp. A soapstone pot is hung over the lamp, continuously providing a soup or cooked meat whenever it is needed. The hunters catch seal, caribou and fish which the women prepare and cook. Sometimes meat is left to freeze and thin slices cut and eaten raw.
Sleeping Inside an Igloo
A mattress of willow twigs is placed on the raised sleeping platform and bedding made from caribou fur or sealskin is laid out. Sleeping bags made from fur are sometimes used. At night, boots and outer clothing are left to dry out in the heat. Often it is warm enough under the bedding for the Inuit to sleep naked. Temperatures of up to 15.6 degrees Celsius have been recorded inside an igloo.