For thousands of years, humans, and plants and animals long before that, have been using frozen "sky water" to keep warm. which sort of doesn't make sense.
几千年来，人类，动植物都使用雪来取暖，这毫无道理。
Because snow is cool.
因为雪是凉的。
You might even say it's… ice cold.
甚至是说冰凉的。
No one knows for sure who built the first igloo, but with the right fit and the right physics, snow can actually warm you better than the inside of a tauntaun.
没人确切知道谁建造了第一个冰屋，但通过合理的构造以及合理的物理，雪保暖的能力要比呆在汤汤的体内还好。 （注：汤汤是星球大战里的虚拟生物，雪地蜥蜴）
"You'll be ok, Luke"!
"没事儿的，卢克！"
So, how can something cold keep you cozy?
但那些冷的东西如何为你保暖呢？
The vast, frozen Arctic is one of the most forbidding environments on our planet, yet, the Inuit have managed to live there for about 5,000 years.
广阔的北极是地球上环境最严酷的地方，但因纽特人却设法在那里生活了大约5000年。
Out on the pack ice, winter temperatures reach 50 degrees below zero , and when it's that cold, surviving means finding shelter.
冬天，冰面上的温度达到了零下50华氏度，在严寒的天气下，找到栖身地才能够存活下去。
It's not an area known for its forests, so nomadic hunters learned to build with the only thing available: snow.
北极并没有森林，因此游牧民学会了用仅有的雪来建造房屋。
Eskimo languages really do have dozens and dozens of different words for snow, because there are a lot of different types, and the type of snow you choose can dictate whether your igloo keeps you warm, or turns you into a Homo sapiensicle.
在爱斯基摩语中，有很多不同的词语都表示"雪"，这些雪被分为不同的种类，根据雪的种类，可以推断出冰屋会为你保暖还是会将你变成"冰冻人"。
To understand this, we need to know a little something about being cold.
为了更好地理解，我们需要了解一些关于"冷"的知识。
When your body temperature starts to plummet – you're feeling heat leave you.
当体温开始下降时，你会感觉慢慢失去了所有热量。
Cold can't move into your body – in fact, there is no such thing as cold.
寒冷并不会进入你的身体，事实上，并没有某样东西是"冷"。
Where have I heard that before?
我是在哪里听到这个观点的？
Oh, right!
哦，对。
Think of heat as an actual quantity of stuff.
如果把热量当作一个有重量的物体。
The more you give away, the colder you feel.
散失的热量越多，你就会感觉越冷。
This trading of heat can happen three different ways: by convection, conduction, and radiation.
热量的传递通过三种方式进行：对流、传导和辐射。
All three are at play in an igloo.
冰屋里面，热量传递的这三种方式都实现了。
A person inside will radiate body heat, which moves around the igloo by convection, and is lost through the walls by conduction.
冰屋里面的人会辐射热量，通过对流作用，热量不断地在屋内流动，但这些热量，由于传导作用，会散发出去。
This is exactly what happens in your house.
这就是屋内所进行的物理过程。
Living insulation does the same thing.
保温材料就是运用的这个原理进行保温。
Fatty tissues like blubber help stop heat transfer in whales and seals, but for animals who don't have as much junk in the trunk, they cover themselves in air.
富有油脂的东西，如鲸脂，阻止了鲸鱼和海豹之间的热量传递，但那些没有很多油脂的动物则用毛来保温。
Sea otter fur, for example, is about a thousand times denser than human hair.
例如，海獭皮，海獭皮比人类的毛发要浓密大约一千倍。
It's snuggly stuff.
它的毛非常舒适。
"This is the softest thing I've ever felt in my life. You are adorable"!
"这是我人生当中摸过的最柔软的东西。你太可爱了！"
But the secret to its insulation power is in its texture.
海獭毛保温的秘密在于毛的纹理。
Otter fur is spiky, so it traps insulating air molecules.
海獭毛尖锐，能够困住保温空气分子。
And that is exactly what snowflakes do.
和雪花是一样的。
Powdery, fresh snow can be up to 95% trapped air.
新鲜的粉末状雪花有时能锁住95%的空气。
This makes it an excellent insulator, but the same way you have to pack it in your hands to make a snowball, it isn't dense enough to build with.
因此，雪花是非常好的保温材料，但如果你想抓一把雪花做一个雪球的话，你会发现做不了，因为密度不够。
Solid ice, on the other hand, makes a good windbreaker, but it's too heavy to lift.
另一方面，坚实的冰防风效果很好，但太沉，拿不动。
Inuit hunters took the Goldilocks approach: the secret to good igloo snow is somewhere in the middle.
因纽特人采用了金凤花的办法：冰屋保暖的秘密在于冰屋的中间部分。
Traditional igloo blocks aren't molded, they're cut out of the ground.
传统的冰屋并没有屋子的形象，人们是直接把地挖一个口子。
That tightly-packed ground snow is dense enough to hold up, but because it still has far more air pockets than a block of ice, it's light, and still a pretty good insulator.
地上的雪非常紧密，可以被拿起来，但其中的空气还是比冰内含有的空气更多，比较轻便，仍然是个好的保温材料。
As usual, animals figured this one out long before humans.
和往常一样，动物比人类更早发现这个秘密。
Polar bears, groundhogs, even birds like grouse all make snow burrows to stay warm.
北极熊，土拨鼠，甚至是鸟类，例如松鸡，都打雪洞来保暖。
And even before that, plants were tucking into snow to avoid death by freezing.
甚至在这之前，植物会把自己卷起来，埋入雪中，以防自己被冻死。
During the warm months, heat energy from the sun builds up in soil, and just like the the roof above your head, a deep covering of snow prevents that heat from escaping onward and upward.
天暖和了以后，土壤吸收太阳的热量，雪就像头顶的屋顶一样，防止热量挥发。
This snowy blanket above stops ice crystals from forming inside plant roots, and shoots, and seeds.
雪就像一席毯子，防止冰花冻伤植物的根部，嫩芽和种子。
Not freezing to death is a pretty good motivator for any animal to get crafty, but our big primate brains took it one step further with igloos.
不被冻死是所有动物变灵巧的动力之一， 每日英语 但是人类的大脑更前进了一步，想出了冰屋。
Their engineering maximizes warmth and stability.
人类最大化雪花的保暖功能和稳定性。
Cartoon igloos look like flat-bottomed half-spheres, but in reality, they're neither of those things!
动画里面的冰屋看起来像平面的半圆，但实际上不是。
If you were to slice a real igloo in half, you'd see a shape called a catenary.
如果把真正的冰屋分成两部分，你可以看见悬链线的形状。
This gradually sloping shape is the same one that would form if you held a chain from both ends and let it droop.
如果你拿着一根链条的两端，让它自由地下落，得到的形状就是悬链线。
A catenary arch distributes weight more evenly than a half circle, without bulging or buckling.
链状比半圆更能承受住重量，并且不会被压弯。
In fact it's one of the most stable arches in nature, so sound that we still use it today.
事实上，这是自然界中最稳固的弓形之一，如今我们仍然常常用到。
Inside, snow houses are carved in different levels.
冰屋里面有分层。
The hot air rises, and the cold air sinks down into the lower part, and away from where you would eat, sleep, and chill.
热空气上升，冷空气下降至低处，远离你吃饭、睡觉以及感到寒冷的地方。
To boot, body heat melts the innermost layer of the walls, strengthening the barrier between you, your airy snow-block insulation, and the frigid great beyond.
人的体热熔化了墙最深处的部分，增强了人、保温层和外边寒冷之间的障碍。
When you live in an igloo, you act as a living furnace.
生活在冰屋内，人类就是活火炉。
Over time, the temperature in your icy abode can hover some 40-60 degrees above the surrounding air, but bring a friend to your igloo party, and you'll get warmer, faster.
冰屋的温度在40-60华氏度之间徘徊，如果你带朋友去你的冰屋里面聚会，那你就会变得更暖和。
Stay cozy, and stay curious!
注意保暖，保持求知心！
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深宸海
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