How can something that is frozen keep you warm?

But countless animals burrow into the snow to keep warm.

And Inuits have been making igloos for centuries.

The question is, how can frozen water actually keep you warm?

OK, full disclosure, I've never actually built a igloo before, and from everything that I'm reading online, they actually seem pretty difficult to build.

So what I'm building right now is actually a quinzee, which is slightly different.

A true igloo is made by stacking snow blocks that are cut from the existing snow pack.

The blocks are stacked in an upward spiral, forming the walls of an igloo.

The key to the whole structure.

A quinzee is more like a snow cave, but instead of digging into the existing snow pack, snow is piled up and packed down before digging it out.

And both keep you warm using the same thermodynamic principles.

But to understand that, we first need to understand that cold doesn't really exist.

Everything, regardless of how solid it feels, is actually comprised of billions of tiny particles that can move around and jiggle with energy.

That jiggling is what we feel as heat.

The faster particles jiggle, the hotter it feels.

And the slower particles jiggle, the colder it feels, all the way down until particles stop moving altogether, which is called absolute zero.

Your body produces heat by turning calories into energy.

And when you feel cold, it's because heat is leaving your body faster than your body can produce it.

Heat is transferred in three different ways.

Radiation, convection and conduction, all of which are happening inside an igloo.

Heat radiates off your body, moves around inside the igloo through convection and eventually is lost to the walls with conduction.

To prevent heat from leaving, you need a way to stop or slow down the transmission of heat.

And typically we do this with some type of insulation, either down or synthetic, that works by trapping millions of tiny little air pockets.

But how do air pockets keep heat from leaving?

Well, it all comes back to that jiggling.

In solid objects, when one or two particles are heated and start to jiggle, they bump into the others, transferring their energy and moving heat through an object.

This is called conduction.

But air is different.

Air particles are spaced farther apart.

And so when those particles jiggle, they don't influence the particles around them as easily.

Instead, heat moves through air by convection.

Warm air molecules are less dense.

And so they float upward until they cool off, causing them to sink.

So if you want to prevent heat from moving through air, all you have to do is stop air from moving.

And that's why even though its particles aren't moving very fast, snow is still a really good insulator because snow is comprised of almost 95% air, air that is trapped so it can't go anywhere.

And it's physically separating the snow particles so it can't conduct very well.

If you've ever tried to melt snow for drinking water, you've probably encountered this.

If you just throw a chunk of snow in a hot pot, it's not going to melt.

Or at least it's going to take a really long time and use a ton of fuel.

That's because only the snow that is in direct contact with the heat is going to melt.

The rest is insulated from the heat by itself.

But if we add just a little bit of water to see the melting process, you'll notice it goes a whole lot faster.

And this huge chunk of snow only makes a small amount of water.

That's because this huge chunk of snow is mostly air.

Now, an igloo is never going to be as warm as a well insulated house, but temperatures inside an igloo can be as much as 40 to 60 degrees warmer than the outside air.

OK, it is about 37 inside, which may not seem all that warm until you see my Bluetooth thermometer outside, which is reading about 12 degrees.

That is a difference of about 25 degrees.

That could mean the difference between freezing to death and surviving.

If the temperature outside was even colder, like it is in the Arctic Circle, where Inuits first invented the igloo, the temperature difference would be even greater.

But that's just one thermodynamic principle.

Remember how we said that hot air rises?

The way igloos are designed take advantage of this, too.

Traditional igloos have a raised platform for sleeping to take advantage of the warm rising air, while the door is set lower to trap any cold air that might make its way inside.

All of this is designed to trap heat and prevent it from escaping.

But where does the heat come from?

Well, as I mentioned earlier, your body is constantly radiating heat, which after a while will raise the temperature inside the igloo.

The more people you bring in an igloo, the warmer it will be.

Or you can even bring something as small as this lantern, which is enough to help bring up the temperature inside the igloo.

It may never feel hot, but compared to the temperatures outside, it's much, much warmer.

I hope you enjoyed this video.

Please like, subscribe and do all those other things.

And as always, thanks for watching.

To understand that, I just post hold.