An igloo, also known as snow house, is a form of shelter built entirely of snow. The primary material used in constructing an igloo is compressed snow since solid ice is known to be a poor insulator. The compressed snow gets shaped into blocks. These blocks are then arranged to form a dome. On the inside, the snow house is terraced so people sleep at the uppermost level, leaving the bottom middle area for working and setting the fire. The coldest air inside the igloo runs towards the bottom allowing the upper portions to stay warm. Remember physics states that as hot air rises, cold air sinks!
The entrance is usually at the bottom to prevent high winds from blowing straight into the igloo and freezing its residents. This door positioning also prevents the fire from blowing out as well. A hole at the top of the snow house prevents smoke from accumulating inside much like houses have chimneys. All these factors make the temperature inside rise to about 20 degrees or so while the outside can record up to negative 50 degrees fahrenheit during the day. 20 degrees may not be comfortable, but it is better than freezing!
The insulating properties of snow keep the inside of an igloo relatively warm. In some cases, animal skins are placed at the door to keep cold air from coming in. And for light, a single block of clear ice is added at the top of the igloo. Much like houses, there are three traditional types of snow houses with different sizes and for various purposes. The small ones were built and used for hunting trips. Middle-sized ones are for family dwellings usually with one single room. Giant igloos are made in groups of two. So that one can be used for special occasions while the other is used for living in. The giant igloos have been known to house up to 20 people!
These snow houses were associated to the Inuit (ˈin(y)o͞oit/) who used the constructions to keep their people warm. It is hard to believe that you can survive at the North Pole in these cold harsh conditions but thanks to the Inuit, scientists today can now use Igloos to stay there and study.
And that’s how Igloos keep you warm. That took some thinking!