Ask A Scientist© General Science Archive

name        Ilisa G.
status       student
age          13

Question -   How do the properties of ice keep an igloo warm?

Hello Ilisa :

          I have never been in an igloo, but I suspect that their main warming
effect is keeping out the wind. You probably have been in a greenhouse, and
have noticed that they are quite warm inside. This has mostly to do with
the fact that walls of the greenhouse prevents air from circulating, and
carrying the heat away. This is a heat transport mechanism called convection.

          Having said that, let us say that it is -30 degrees outside, but
the wind is not blowing. Does it still make sense to build an igloo ? Yes.
The inside of the igloo can be warmed to the melting point of water by your
body heat, or a campfire, and the ability of ice to conduct heat is not all
that good, so that the inside of the igloo can be maintained at this higher
inside temperature.

Jim Rubin
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Ilisa,

There is nothing about the properties of ice that keeps the interior of
an igloo warm. From its melting point of 32 F (0 C) on down to lower
temperatures, ice can be as cold as its environment. An igloo can serve
as a shelter because the walls are made rather thick -- and therefore
they are resistant to heat flow through them. And too, the interior is
heated by oil lamps and the body heat of its occupants.

Use the Internet and various web encyclopedias to search the keyword,
"igloo.," It's likely you will discover more information that bears on
the answer to your question.

Regards,
ProfHoff
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  First, the ice and snow used to make an igloo serves as a wind break, and
wind is a major factor in the wind chill index.

Second, ice and snow have a low coefficient of thermal conductivity [0.005
and
0.00026 (cal/sec)/(cm^2x C./cm) ] which means ice and snow do not leak a lot
of heat by conduction.

Vince Calder
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