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Igloo 101
Answer Key


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1. (a) on sea ice

Inuit usually built their winter villages on sea ice in order to be as close as possible to their food sources—fish, seals, and whales. They looked for areas on the ice that provided some buffer against the freezing winds of the Arctic, such as snow ridges or cliffs.


2. (c) a layer of snow formed in a single drift

Almost any snow will work for an experienced igloo builder in a pinch, but the best kind is a deep layer of packed snow from the same drift. Snow formed from several drifts is likely to have hollow spaces that can compromise the integrity of an igloo. Also, snow that has lots of ice in it crumbles easily. To test the snow, native peoples used a snow probe made of antler or bone. If it penetrated the snow smoothly and deeply the snow was likely to be good building material.


3. (b) a catenary

You might not notice it unless you carefully study photographs of igloos, but they are not perfect hemispheres. Their so-called catenary shape means that their arc is higher at its highest point than it would be if it were forming a true semicircle—but not nearly high enough to be called a cone. As an igloo settles in the snow, it compresses slightly and loses some of its height. A hemispherical structure might not survive the settling process intact: the sides could buckle and the roof collapse.


4. (c) just a knife

It may be a little daunting to picture yourself in the snow tasked with igloo construction using only a single knife, but the experts insist that's all you really need. Early native snow knives were like saws made of caribou antler or ivory, with indentations in the handle for easy gripping. (After contact with Europeans and Americans, they sometimes used iron blades.) A snow knife was generally eight to 12 inches long and one or two inches wide. It was used for marking the snow as well as cutting, removing, and shaping the blocks.


5. (b) inside it only

You can't tell from this famous image from the 1922 documentary "Nanook of the North", but an igloo builder does all his work from inside the footprint of the structure. The builder might have a helper on the outside, but the primary builder would always stand inside the circumference of the igloo, cutting blocks and building the structure from within right down to the final block. Each layer of blocks was made to lean in a little more than the previous one until the proper shape was formed.


6. (a) add both

Igloos usually have chimneys and windows. Native peoples used freshwater ice three or four inches thick or a piece of animal gut to create one or more rectangular or trapezoidal windows in their igloos. Windows allowed light to enter and made it possible to see who was coming. Igloos would also have a small chimney, which was simply a hole cut off center at the top of the structure to provide air circulation. If the chimney were in the very center of the roof, the igloo could cave in. Without a chimney, the igloo could melt.


7. (c) 65 degrees

It seems amazing, but these ingenious snow shelters are very comfortable inside, averaging about 65 degrees warmer than the outside air with windchill, especially when a lamp is burning. Snow has excellent insulating properties, and an igloo works like an inverted container to trap rising warm air. Often native peoples would line the inside of their shelters with animal skin, which increased the amount of heat trapped and prevented structural melting. If the house became too cold, they could plug the chimney with moss or leather; if it became too warm, they could widen the chimney.


8. (c) it maintains itself, then you move

Igloos are low-maintenance and durable. Whole families could stand on their roofs, and children sometimes played on them and slid down their sides. The inside of an inhabited igloo was constantly melting a little bit and freezing up again, glazing it with a thin shell of ice. This film would seal any tiny openings and bind the structure tightly together. When spring arrived and temperatures rose, igloos would begin to melt quickly. But it was time to move then anyway to follow game and live in tents for the summer.


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