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Cool as Ice


The world we live in is full to the brim with compelling tales and curious phenomenon. Everything from the workings of nature to the endeavors of man can capture our attention and these stories spark interest in kids everywhere. When we were but curious younglings we were exposed to many captivating ideas through stories and TV shows. But as kids, we were not ready for the full explanations to some questions: how do clouds form and stay afloat? How does electricity work? Why do we need to breathe to live? So we got simplified answers, just the basic facts. Then, when we meet these questions again at an older age, when we are ready for a more complex answer, we already have an interest in them. But sometimes, the stories and tales you hear as a kid don’t appear in your life again until you are very much older, and suddenly you realize that you never followed up on those questions.

That happened to me, just now. I was in my car, driving home and listening to the radio when I heard an ad for a company called ‘Igloo’. The word igloo always reminds me of the ‘Magic School Bus’ episode that I watched when I was a kid, in which they go to the Arctic and build and igloo. The idea of some kind of house made of snow and ice caught my attention then, and the interest I found in the subject when I was a kid was rising in me again. Suddenly I figured that everything I knew about these snow huts was what I learned about it as a kid. All I had were simplified answers - I knew an igloo was somehow keeping the warmth inside, but I had no idea how it worked, nor anything else about it. It felt wrong to me that I found an interest in this, but all I knew about it was very basic information. I decided to write down what I know about igloos once I got home, then read about them for as long as it interests me, and compare what I knew about them to what I found out.

So here’s the ‘before’ picture, the extent of my previous knowledge about igloos, mostly derived from cartoons and kids’ books: Igloos are a type of structure that is tied to Alaska and Eskimos, that functions as a house or shelter. The igloo itself keeps whatever heat that is inside of it, so if you start a fire in it you can keep somewhat warm. It’s built in the shape of an upside-down half-sphere, made of blocks of ice. It has a tunnel to get in and out of, and the inside of the igloo is a flat and round space that people can stay in. I’m not sure how the heat is kept inside the igloo. I’m not sure if the igloo is supposed to be a temporary shelter or if it is supposed to be a permanent home - if the latter, I don’t know if people still use it today or not.

And here’s the ‘after’ picture, everything I found out about igloos:

The igloo is a type of structure that is associated with people who are native to cold areas - Canada’s central Arctic and Greenland’s Thule areas - not Eskimos, per se. In the native languages of those areas, the word Igloo literally means ‘house’ or ‘structure’, and can refer to anything from a tent to a building. The word that refers specifically to a snow igloo is Igloovijag (plural - Igloovijait). The igloo functions as a house or shelter in the cold conditions of the Arctic, and different igloos can come in a variety of size that are directly connected to the function that the igloo serves (I’ll come back to it a little later).

But how warm can an igloo get? Surrounding yourself with ice seems a little counterproductive if what you’re trying to do is get warmer. Well, it seems that even though it goes against my intuition, an igloo can be very effective - while the temperature outside the igloo is -45°C (-49°F), a good igloo can keep a temperature of somewhere between -5°C (23°F) and 5°C (41°F), using only body heat. Now, it is obvious that 0°c isn’t exactly warm, but achieving even that when you are surrounded by snow and ice and using only body heat is pretty amazing. By lighting a small fire inside the igloo, or covering the walls of the igloo with hides or other insulators, you can get even warmer.

So you’re now wondering how does it work? I did too. The main property that allows an igloo to hold its warmth is the material it’s made of. An igloo is not made of blocks of ice, as I thought it to be, but blocks of snow. Not just any snow though, the snow has to be of a certain compression. Fresh snow is too fluffy and weak to build with. Snow that had time to set and is too compressed will not be able to keep the heat as well. Snow that is of the right compression, the one that is perfect for igloos, occurs in certain conditions. With experience, you can recognize the type of snow that is suited for the job and use it to carve blocks to build with. The fact that it’s somewhat compressed gives it the strength that is required to hold the weight of the igloo, while also keeping a lot of its many air pockets intact between the snowflakes.

Snow naturally has little air pockets in it, and the air acts as an insulator that keeps the warmth inside. What makes the air a good insulator is the fact that it is intrinsically a poor heat conductor - it is not good at transferring heat. In order for a certain substance to be an effective conductor it has to have a high heat capacity and density - air has both low heat capacity and density. Not being a good conductor, there’s only so much heat that the air in the igloo walls can absorb, and so most of the heat is reflected back into the igloo.

The fact that air is a good insulator is applied in many other ways. The clothes we wear and blankets we use work in a similar way -  they keep our body heat inside them by having air pockets act as an insulator in the fabrics. Another great example is those foam cups that are used for hot beverages. Think as a foam cup as the igloo wall - these foam cups have a surprisingly large percentage of air bubbles in them (somewhere over 90%, usually), just like the snow of an igloo. That allows you to put a liquid that is near boiling in them, and all the while you are still able to hold the cup from its outer side - the heat from the drink does not conduct well towards the outside of the cup.

There are ways to help conserve the heat inside an igloo, by building an igloo smartly. The first thing you can do is build the igloo in a spot that will help conserve heat. To do that, an igloo is usually built in the spot where the snow has been carved from. When you harvest the snow, it leaves a hole in the ground. By building in the hole, you surround yourself with a generous layer of extra insulation, at least at the lower parts of the igloo. The next thing you can do is use the fact that warm air rises and cool air sinks. I always thought that an igloo is just one flat level, but I learned that sometimes an igloo is built with 3 different levels. The top level, where all the warm air will rise to, is where people usually sleep. The middle level is where you light a fire and have some workspace, to cook in, for example. And the lower level, the ground level, acts as a cold sump, to collect all the cold air. The warm air in the igloo will float above the cold sump and spread in the levels where people stay. The lower level is where the tunnel to enter and exit the igloo is located. This tunnel also has a smart design to it, to keep the cold out. This tunnel is built with a downwards slope, if you’re looking at it from the outside, and that helps with keeping the cold wind from blowing inside the igloo.

Wikimedia - Anuskafm

So how do they build the igloos? I’ve read about igloos that used wood or even animal bones as scaffolding, but that’s not what interests me - I’m all about the classic igloos. As I said before, the first step is choosing the right type of snow, and carving it into bricks. Then, you lay the bricks, one by one,  in a circular way, that keeps rising as you add bricks. The shape of the igloo is very important, though, and it turns out that it isn't just a simple half-sphere, like I thought it was. The ideal shape of an igloo is more paraboloid and known as a Catenary. The catenary, which is more U-like in its shape, is the ideal geometrical shape for a self-supporting arch of uniform density and thickness. It is the strongest shape to support such a construct. When you finish stacking the bricks for the igloo, you can use more snow to cover the outside and insulate the igloo better, and then give it a few hours to set. Once it’s all done, a well-built igloo can support the weight of a grown man standing on its tip, mostly due to it being of a catenary shape. The heat inside the igloo can add to its strength - the innermost layer of snow of the walls may melt a little, and then refreeze because of cold from other layers, turning it to a layer of strong solid ice. It’s important to remember to leave a small hole on the top of the igloo, to let smoke from the fire or cooking escape the igloo. Another interesting building method is using a block of clear ice in the top or one of the sides of the igloo, to let light sip into the igloo.

Now, I thought that igloo was supposed to be a permanent housing solution, but the more I think about it, the less it makes sense. Even if an igloo is a bubble of nice warm air compared to the rest of the Arctic, it still is too cold to spend your whole life in one. Also, I’m pretty sure that no one would find the experience of having your house melt every summer an enjoyable one. So what were they used for? Well, the most common type is the small type of igloos, which is easier to build and it served for short periods of time. Consider having to leave the village for a few days to go on a hunting trip in the Arctic - the igloo serves as a tent that is specialized for this specific environment. The medium type, the family-size igloos, served for longer periods of time. These were used as shelter during the winter, perhaps when the village is still new and permanent constructs were not built yet. And the larger type, that served as gathering halls for the winter - I’m guessing that it was easier to build large constructs from snow, as it was the most abundant resource in the area. None of the igloos really were for permanent stay.

And that gives an answer to the most burning question everyone has: do people still use igloos today? Well, yes. People who live in these cold areas that still rely on hunting for their food. Many others build igloos in a more recreational way. People who go on hunting or fishing trips in the Arctic will find a lot of use in building an igloo. Mountain climbing enthusiasts may find themselves building a snow hut, as well. Survival experts instruct people who go on trips to extremely cold places on how to build an igloo - it can save lives. Furthermore, igloos are used in a more commercial way, also. You can find igloo villages around Europe, in which you can rent a cozy little igloo for a few days, like a snowy hotel room. In Kakslauttanen Igloo Village, Finland, you can rent your own snow igloo, eat at an igloo restaurant and get married in an ice-chapel. Some of these places, in the northernmost parts of europe, offer igloos made of clear ice, those provide the opportunity to witness the northern lights at room temperature.

It’s easy to see the differences between my ‘before’ and ‘after’ pictures - what I knew about igloos as a kid was not even the tip of the iceberg (sorry). I’m glad to have learned more about these snow huts and how they are used - this information is already proving handy, when I find myself in awkward social situations and in a dire need for an ice-breaker (that is not even a good pun). Despite the fact that I haven't really given any thoughts to igloos in years, and I could have gone on living my entire life without thinking of them still, I now am hoping that one day I’ll have a chance to go have some fun with igloos. But, you see, it may be harder than I initially thought - it seems that climate change is having its bothersome effect evident here, as well. With the temperatures rising around the world, the conditions that lead to the formation of the right type of snow for igloos are changing. In many places people are reporting that it is getting harder and harder to find fitting snow to build an igloo. Snow in many areas where igloos are most used is either too soft or too hard to work with. Hunters have also mentioned that the change in climate has turned the weather unpredictable. When they go hunting, it is either too warm for an igloo or the snow is not right, so they use tents instead, but more often than not, the weather turns for the worse and they find themselves in dangerous situations. It’s all kind of gloomy, and I hate to finish on such sad note, but I found it too interesting to not at least mention, and it kind of… snowballed from there.

Additional notes and sources can be found here.

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Thank you for reading,