Igloo from Wikipedia

Presented for someone who call me as "Igloo"

An igloo translated sometimes as snowhouse, is the Inuit word for house or habitation, and is not restricted exclusively to snowhouses but includes traditional tents, sod houses, homes constructed of driftwood and modern buildings.


Igloo as a snowhouse
When used to refer to a snowhouse an igloo is a shelter constructed from blocks of snow, generally in the form of a dome. Although igloos are usually associated with all Inuit, they were predominantly constructed by people of Canada's Central Arctic and Greenlands Thule area. Other Inuit people tended to use snow to insulate their houses which consisted of whalebone and hides. Snow was used because its low density makes it an insulator. On the outside, temperatures may be as low as −45 °C (−49.0 °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.

Traditional Types
There were three traditional types of igloos, all of different sizes and all used for different purposes.

The smallest was constructed as a temporary shelter, usually only used for one or two nights. These were built and used during hunting trips, often on open sea ice.

Next in size was the semi-permanent, intermediate-sized 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 of the igloos was 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.

Construction
The snow used to build an igloo must have sufficient structural strength to be cut and stacked in the appropriate manner. The best snow to use for this purpose is snow which has been blown by wind, which can serve to compact and interlock the ice crystals. The hole left in the snow where the blocks are cut from is usually used as the lower half of the shelter. Sometimes, a short tunnel is constructed at the entrance to reduce wind and heat loss when the door is opened. Due to snow's excellent insulating properties, inhabited igloos are surprisingly comfortable and warm inside. In some cases a single block of ice is inserted to allow light into the igloo. Architecturally, the igloo is unique in that it is a dome that can be raised out of independent blocks leaning on each other and polished to fit without an additional supporting structure during construction. The igloo, if correctly built, will support the weight of a person standing on the roof. Also, in the traditional Inuit igloo the heat from the kulliq (stone lamp) causes the interior to melt slightly. This melting and refreezing builds up an ice sheet and contributes to the strength of the igloo. The sleeping platform is a raised area compared to where one enters the igloo. Because warmer air rises and cooler air settles, the entrance area will act as a cold trap whereas the sleeping area will hold whatever heat is generated by a stove, lamp or body heat.

source: http://en.wikipedia.org/wiki/Igloo