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, because snow is cool. You might even say it's ice-cold.
人類數千年來，而動植物更是早在那之前，就利用天降的凍水來維持溫暖，那有點不合邏輯，因為雪是冷的啊。你甚至可以說它很冷酷。
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.
沒人確切知道是誰蓋了第一座冰屋。不過方法對了再加上正確的物理學，雪其實比待在咚咚獸的肚子裡更能溫暖你。
"You'll be okay, Luke."
「路克，你會沒事的。」
So, how can something cold keep you cozy?
那麼，一個冷冰冰的東西要怎麼讓你保持溫暖舒適呢？
The vast frozen Arctic is one the most forbidding environments on our planet. Yet the Inuit have managed to live there for about 5,000 years. Out on the pack ice, winter temperatures reach 50 degrees below zero, and when it's that cold, surviving means finding shelter. It's not an area known for its forests, so nomadic hunters learn to build with the only thing available: snow.
遼闊又天寒地凍的北極是我們星球上最險惡的環境之一。然而因紐特人卻設法在那居住了近五千年。在浮冰之上，冬季低溫可達攝氏零下五十度，而當天氣那般寒冷，生存就意味著找到容身之處。北極可不是以森林聞名的地區，因此遊牧獵人們學會用唯一的資源建造房子：也就是雪。
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.
愛斯基摩語中確實存在各式各樣形容雪的字彙，因為雪有許多不同型態。而你選擇的雪的種類會決定你的冰屋是能讓你保暖還是把你變成一根人肉冰棒。
To understand this, we need to know a little something about being cold. When your body temperature starts to plummet, you're feeling heat leave you. Cold can't move into your body. In fact, there's no such thing as cold. Where have I heard that before? Oh, right!
要了解這，我們得稍微認識一下「冷」這件事。當你的體溫開始驟降，你會感到熱度離開身體。冷並不能進到體內。實際上，並沒有冷這回事。我在哪聽過那句話？喔，對啦!
Think of heat as an actual quantity of stuff: The more you give away, the colder you feel. And this trading of heat can happen in three different ways: by convection, conduction, and radiation. All three are at play in an igloo. A person inside will radiate body heat, which moves around the igloo by convection and is lost through the walls by conduction. This is exactly what happens in your house.
將熱想成有實質的量的物體：你給出越多就覺得越冷。而這種熱的交換會以三種不同方式進行：通過對流、傳導及輻射。這三種在冰屋內都有作用。裡面的人散發體溫，熱度透過對流在冰屋內移動，再經由傳導從牆面散失。這正是你屋子裡的情況。
Living insulation does the same thing. 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. Sea otter fur, for example, is about a thousand times denser than human hair. It's...snuggly stuff.
動物的隔熱也是相同做法。像是脂肪層那樣的脂肪組織幫助阻止鯨魚和海豹的體溫轉移，但那些沒那麼肥滋滋的動物，牠們會以空氣來包覆自己。好比說，海獺的毛皮大約比人類毛髮密集一千倍。那是很...舒服的玩意。
"This is the softest thing I've ever felt in my life. You are adorable."
「這是我這輩子摸過最柔軟的東西。你好可愛喔。」
But the secret to its insulation power is in its texture. Otter fur is spiky, so it traps insulating air molecules. And that is exactly what snowflakes do.
不過海獺毛禦寒能力的秘密在於它的質地。海獺毛刺刺的，因此會困住隔熱的空氣分子。那正是雪花的作用。
Powdery fresh snow can be up to 95 percent trapped air. 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. Solid ice, on the other hand, makes a good windbreaker, but it's too heavy to lift. Inuit hunters took the Goldilocks approach: The secret to good igloo snow is somewhere in the middle.
剛降下的粉狀雪可能含高達百分之九十五的空氣。這使它成為絕佳隔熱體。不過就像你得用手擠壓才能做雪球一樣，那種雪的密度不夠拿來蓋房子。另一方面，冰塊是很好的防風材料，不過它太重了很難搬。因紐特獵人採取金髮姑娘的辦法：適合建冰屋的雪介於粉狀雪和冰塊之間。
Traditional igloo blocks aren't molded; they're cut out of the ground. 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.
傳統建冰屋的冰磚不是模鑄的；它們是從地面切割出來。地面那種厚實的雪的密度足以支撐，但由於它相較冰塊還是多出許多氣孔，它的重量輕盈，仍是不錯的隔熱體。
As usual, animals figured this one out long before humans. Polar bears, groundhogs, even birds like grouse all make snow burrows to stay warm. Even before that, plants were tucking into snow to avoid death by freezing. During the warm months, heat energy from the sun builds up in soil, and just like the roof above your head, a deep covering of snow prevents that heat from escaping onward and upward. And this snowy blanket above stops ice crystals from forming inside plant roots and shoots and seeds.
老樣子，動物們老早就比人類先想出這種方法了。北極熊、土撥鼠，就連松雞那種鳥都會在雪中挖洞取暖。甚至更早以前，植物就會藏在雪中來避免凍死。溫暖的月份間，太陽的熱能在土壤中累積，就像你頭上的屋頂，一層厚厚的積雪能預防熱能向上逃散。而上方這種雪毯讓冰晶不會在植物根部、苗和種子中形成。
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. Their engineering maximizes warmth and stability.
不被凍死是促使任何動物變聰明的絕佳動力，不過我們靈長類的大腦袋瓜更上一層樓，蓋出冰屋。其中的工學讓暖度和穩固度都有極致表現。
Cartoon igloos look like flat-bottomed half spheres, but in reality, they're neither of those things. If you were to slice a real igloo in half, you'd see a shape called a catenary. This gradually sloping shape is the same one that would form if you held a chain from both ends and let it droop. A catenary arch distributes weight more evenly than a half circle, without bulging or buckling. In fact, it's one of the most stable arches in nature, so sound that we still use it today.
卡通裡的冰屋看起來像底部平平的半圓，但現實中，冰屋都不是那些樣子。如果你把一座真正的冰屋切一半，你會看到一種叫作「懸鏈線」的形狀。這種漸斜的形狀和你拿著鏈子兩端讓它垂墜的形狀一樣。懸鏈線狀的拱型比半圓更能平均分散重量，不會鼓起來或變形。事實上，它是大自然中最穩固的拱型之一，十分牢固，因此我們至今仍在使用。
Inside, snow houses are carved in different levels. The hot air rises, and the cold air sinks down into the lower part, away from where you would eat, sleep, and chill. 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. When you live in an igloo, you act as a living furnace. Over time, the temperature in your icy abode can hover some 40 to 60 degrees above the surrounding air. But bring a friend to your igloo party, and you'll get warmer faster.
冰屋內部被鑿成不同高度。熱空氣上升，冷空氣則下降到較低處，遠離人吃飯睡覺和休憩的地方。此外，體溫融化牆壁最內層，強化你和輕盈的雪磚隔熱層及嚴寒的外界之間的屏障。當你住在冰屋內，你就是個活動暖爐。隨著時間過去，你冰冷住所內的溫度可能來到高於周遭溫度約攝氏四十到六十度之間。不過帶一個朋友到你的冰屋開趴，你會更快覺得暖呼呼。
Stay cozy and stay curious.
保持溫暖舒適，保持一顆好奇的心。
- 「肯定、無疑」- For Sure
No one knows for sure who built the first igloo.
沒人確切知道是誰蓋了第一座冰屋。 - 「有影響」- At Play
All three are at play in an igloo.
這三種在冰屋內都有作用。 - 「在另一方面」- On The Other Hand
Solid ice, on the other hand, makes a good windbreaker, but it's too heavy to lift.
另一方面，冰塊是很好的防風材料，不過它太重了很難搬。 - 「除此之外、而且」- To Boot
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.
此外，體溫融化牆壁最內層，強化你和輕盈的雪磚隔熱層及嚴寒的外界之間的屏障。
