If you ever find yourself stranded in the Arctic tundra, you might want to look for an igloo to shelter in. Igloos are snow houses that have been used by the Inuit people for centuries to survive the harsh winters. But how can a house made of snow keep you warm? Here’s the science behind these ingenious structures.
An igloo is not made of solid ice, but of compressed snow. Snow is actually a good insulator of heat because it contains air pockets that trap heat and prevent it from escaping. “Snow is basically semi-frozen water or frozen crystalline water. Contrary to intuition, snow has actually got very good insulating properties. Solid ice on the other hand, is not a good insulator compared to compressed snow,” explains an article on Physics Stack Exchange.
The inside of an igloo is also designed to maximize the heat retention. The igloo is divided into levels, where the upper level is for sleeping, the middle one is for fire and cooking, and the lower one is for cold air to sink. The entrance to the igloo is at the bottom part, which blocks the cold air from blowing directly into the interior. A small hole is built into the top of the igloo to allow smoke to escape.
The main source of heat inside an igloo is your own body heat and the fire. “An igloo keeps you warm by trapping your body heat,” says an article on Science ABC. “The air molecules trapped between the tiny ice crystals create air pockets, which act as excellent insulators that prevent heat loss due to convection. Some engineering also goes into the design of the inside of an igloo.”
The temperature inside an igloo can be much warmer than the outside, ranging from -7 to 16 °C (19 to 61 °F), depending on the body heat and the fire. “A small igloo can be built by a couple of hunters in 30 minutes to an hour under most circumstances. In areas where temperatures can drop to -50 degrees, you may find the inside temperature of an igloo to be 20 to 70 degrees warmer than the outside temperatures,” says an article on Buyers Ask.
The Inuit people are experts at building and living in igloos. They are one of the most widespread and toughest aboriginal groups in the world, having survived one of the most unpleasant climates for millennia. “This is how igloos stay warm: the hard snow walls of the igloo are good insulators that keep in body heat and the heat generated by oil lamps (known as qulliq.) This is why traditional igloos are made out of snow rather than ice. Solid ice does not retain heat as well as blocks of compressed snow,” says an article on The Canadian Encyclopedia.
So, next time you see an igloo, don’t think of it as a cold and icy structure. Think of it as a cozy and warm home that showcases the amazing properties of snow and the ingenuity of the Inuit people.
– Why is the air inside an igloo warmer than its outside?, Physics Stack Exchange, Jan 14, 2021
– How Does An Igloo Keep You Warm?, Science ABC, Feb 14, 2022
– How Igloos Work, HowStuffWorks, no date
– Igloo, The Canadian Encyclopedia, Dec 19, 2006