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Posted by on Mar 24, 2016 in Tell Me Why |

What Keeps an Igloo Warm Inside?

What Keeps an Igloo Warm Inside?

If you were an Eskimo living in the far north of Canada, you might build your winter house from blocks of snow and sleep on a bed of snow covered with furs. Even though it is made of snow, an igloo is quite warm inside because snow is a good insulator.

The snow walls keep the heat in while shutting the cold out. Oil lamps light the igloo and provide heat to keep the Eskimo family warm. The cold outside keeps the snow house from melting. The family crawls into their snow house through a low tunnel that faces away from the wind, to keep out the cold air.

Cooking is easy and safe in an igloo as long as the structure is ventilated with a hole at the top. The principle behind an igloo is hidden in the material it’s constructed out of. Igloos are normally built from compressed snow, which is sawn into blocks, and then these blocks are stacked around a hole, which is dug out after the blocks have been set.

Solid ice is a poor insulator, when compared to compressed snow. The snow has many more air pockets per cubic foot, and is also lighter. Also, igloos do not have flat bottoms.

The inside of the igloo is tiered, or terraced, the uppermost level being where the people sleep, the middle is where the fire is and the work takes place, and the bottom level actually is a “cold sump”. The principle is that all the coldest air from inside the igloo runs downward off the terraces and collects in the bottom, thus allowing the upper portions to stay warmer.

The entrance for the igloo is usually at the bottom, and includes at least one right angle, which keeps the high winds from blowing straight into the igloo and chilling the residents or blowing out the fire. They also all have a small hole on the top that keeps the smoke from building up inside the igloo.

All of these factors take advantage of underlying physics, and the temperature inside an igloo is likely to be 20 degrees or so, while the outside temperature in northern regions can drop down to -50 degree Fahrenheit during the daytime. 20 degrees may not be what some consider to be comfortable, but a 70 degree difference is certainly welcome somewhere so cold.

An igloo, also known as a snow house or snow hut, is a type of shelter built of snow, typically built when the snow can be easily compacted. Although igloos are stereotypically associated with all Inuit, they were traditionally associated with people of Canada’s Central Arctic and Greenland’s Thule area. Other Inuit people tended to use snow to insulate their houses, which were constructed from whalebone and hides.

Snow is used because the air pockets trapped in it make it an insulator. On the outside, temperatures may be as low as −45 °C (−49 °F), but on the inside the temperature may range from −7 °C (19 °F) to 16 °C (61 °F) when warmed by body heat alone.

There are three traditional types of igloos, all of different sizes and used for different purposes. The smallest were constructed as temporary shelters, usually only used for one or two nights. These were built and used during hunting trips, often on open sea ice.

Intermediate-sized igloos were for semi-permanent, family dwelling. This was usually a single room dwelling that housed one or two families. Often there were several of these in a small area, which formed an Inuit village.

The largest igloos were normally built in groups of two. One of the buildings was a temporary structure built for special occasions, the other built nearby for living. These might have had up to five rooms and housed up to 20 people. A large igloo might have been constructed from several smaller igloos attached by their tunnels, giving common access to the outside. These were used to hold community feasts and traditional dances.

Content for this question contributed by Bruce Nolan, resident of Alton, Madison County, Illinois, USA