You must have the saying that it is hard to sell fire in hell or the man is as crooked as a corkscrew; he could sell ice to an Eskimo.
The saying may not be significant to you if you do not know what the hell was, or what happens in Eskimo place. I would talk a bit about the latter. Eskimos, not to be confused with Canadian Football Team of the same name, are an indigenous group of people who inhabit the cold areas of eastern Siberia, Greenland, Alaska, and northern Canada. Though, the name has come to be considered offensive by some section of people in Canada who instead prefer to be referred to as Inuit or Inuk. That is not the objective of this post. In all, Eskimos have snow; you would be one powerful super-convincing salesman to sell ice there :)
The people are mostly a hunter-gatherer society who makes their living via fishing and game hunting.
Not minding the distance separating the different group of people known as Eskimo today, they still share one thing in common: very low temperatures. Temperature could get as low as -31.2°C or -24.16°F and even colder (-58°C), coupled with strong winds.
It is cold, but they build structures known as igloos to keep them warm. What are igloos made of you may ask? Well, it is made of ice. How can ice keep you warm in an icy environment? There is an explanation for that and _that is the objective of this post.
Image from Pixabay: A Modern Day Igloo
The first igloo was built by an indigenous tribe of people who knowingly or inadvertently took advantage of some laws of physics. Or they could have just been a bored bunch of guys who said, "Hey Man, let's put the ice together and see what the inside would look like."
Of course, I imagine this as I have no idea how the plan to build an igloo came into play.
The Inuit has managed to live in this almost forbidden territory of the world for nearly 5000 years.
Survival of the frigid temperature environment could only happen if someone is in a shelter and since the only thing you could see for hundreds of miles are snow, and so they learnt to use snow to build those dome-shaped structures called igloo.
There has been this debate that there are 100 Eskimo words for snow due to many types of snow available. But in reality, there are only 50 Eskimo words for it.
The Science of Cold
For a human to feel cold what happens is that the body loses heat and you feel cold. This is just the basics of air cooling in air conditioners and refrigerators. The heat gets exchanged via radiation, conduction and convection.
These three methods of heat transfer come into play while inside the ice-hut known as the igloo. The body radiates heat which is circulated inside the room via convection and this heat escapes through the ice walls through the process of conduction.
Summary of the Heat Transfer Process in an Igloo
Radiation: Any hot object radiates heat. Our bodies are warm ( the adult body temperature is 36.5–37.5 °C or 97.7–99.5 °F).
Convection: The radiated heat rises with cooler air sinking downwards and setting up a convection current
Conduction: The heat escapes through the walls of the igloo with the snow acting as the barrier.
In nature, some animals come already "cold proof" via the makeup of their system. For instance, the blubber (fatty tissue) beneath the skin of Arctic polar bear does not only act as a reserve "tank" of for energy or food reserve but also as a thermal insulator. They do not allow heat to be lost through the body easily hence keeping them warm at temperatures of -37°C (-34°F) while maintaining a body temperature of 37°C (98.6 °F).
But not all animals have this much layer of fats, but they make do with hair capable of trapping air molecules which acts as an insulator. An example is the sea otter.This same insulating property of the sea otter's air-molecules-trapping insulating hair is what the powdery snow possesses too. Powdery snow can trap over 90% of air giving it that crunchy effect when you step on a fresh snowfall.
Building a traditional igloo requires cutting the igloo blocks straight out of the ground. This is done rather than looking for a block of ice due to the fact that the one from the ground have more air pockets and its less dense making it a better insulator.
The man may be a little late in this game as animals such as polar bears, birds, etc. already build ground burrows to keep them warm in the snow.
But igloos are built with a much more engineering knowledge in place. The shape of it is made in a catenary arch style or the form of an upside down hanging chain.
This shape enables for an even distribution of load of the building. That makes an igloo to be very stable without the risk of crashing down on the occupants.
Notice the raised platform on the inside of the platform. It was done to allow cold air to go down and hot air to rise to keep the inside warm. The more there are people inside, the more body heat is generated and the more heated the inside becomes. The interior has a tier (steps) or upper chamber where people sleep. The coldest air thereby runs on the lower chamber of the layer while the top part retains warm.
The centre is where the fire is kept with the ventilation at the top allowing smoke to escape.
The inside the temperature ranges from −7 °C (19 °F) to 16 °C (61 °F) with no outside heat source but only by body warmth. Want to keep more warmth in an igloo? Invite a friend over.
References
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