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Wow, Squeaks, that’s incredible!
哇，吱吱，太不可思议了!
Squeaks and I are learning about Antarctica, and this says that the biggest glacier in the world is there.
我和吱吱正在学习关于南极洲的知识，这上面说世界上最大的冰川就在那里。
We’ve talked about glaciers here at SciShow Kids before, so you might remember a bit about them.
我们之前在儿童科学秀上讨论过冰川，所以你可能还记得一点。
Exactly!
一点也没错!
Glaciers are kind of like giant ice cubes on Earth.
冰川有点像地球上的巨大冰块。
You can find them in places where it’s so cold, the snow doesn’t fully melt away in the spring.
你可以在很冷的地方找到它们，在春天雪没有完全融化的时候找到它们。
They form when a lot of snow falls in the same place every year, and gets packed down over a long time — sometimes, more than 100 years.
冰川是每年在同一个地方大量降雪形成的，而且经过很长时间的堆积——有时超过100年。
Eventually, the packed snow freezes into ice, getting thicker and thicker, until you have a giant piece of it.
最终，堆积的雪冻结成冰，冰块越来越厚，直到堆积成巨大的冰块。
And the ice gets so heavy that it starts to move, slowly sliding across the ground.
冰变得很沉重，以至于它开始移动，慢慢地在地面上滑动。
We call this giant, moving ice a glacier.
我们称这个巨大的移动的冰为冰川。
Nowadays, you can only find glaciers in a few places — usually high up in mountains or in super cold places like Antarctica.
如今，你只能在少数几个地方找到冰川——通常是在高山上或像南极洲这样的超级寒冷的地方。
But long ago, a lot of Earth used to be covered in glaciers.
但是很久以前，地球上的很多地方都被冰川覆盖着。
That’s a really good question.
这是一个非常好的问题。
Squeaks asked how we know the Earth used to be covered in glaciers, when most of them aren’t here anymore.
吱吱问我们如何知道地球曾经被冰川覆盖，而现在大部分冰川都已经消失了。
Well, those glaciers left clues behind, and we can still see those clues today!
嗯，这些冰川留下了线索，我们今天仍然可以看到这些线索!
When glaciers move, they change the land that they move over.
当冰川移动时，它们会改变所经过的土地。
Glaciers can pick up dirt, sand, and even big rocks, and push and scrape them against the Earth.
冰川可以携带灰尘、沙子，甚至是大岩石，并推动和摩擦地球。
And when the glacier is gone, those signs are still there.
即使冰川消失了，这些迹象仍然存在。
Here, I have a good way to show this.
在这里，我有一个很好的方式来展示这个。
Let’s make a model!
让我们做一个模型吧!
You can use models to make the world easier to understand — especially if the thing you want to learn about is too big, far away, or rare to study in person.
你可以用模型让这个世界更容易理解——特别是当你想要了解的东西太大、太远或亲自研究的人太少的时候。
In this case, glaciers move so slowly, it’s hard to see them in action.
在这种情况下，冰川移动非常缓慢，很难看到它们的行动。
But we can make a model of a glacier with this ice cube tray!
但我们可以用这个冰块托盘做一个冰川的模型!
If you want to build your own glacier model, you’ll need an ice cube tray; some small rocks, sand, or dirt; water; some modeling clay; a freezer; and a grown-up helper.
如果你想建立自己的冰川模型，你需要一个冰块托盘; 一些小石头、沙子或泥土; 水; 一些粘土; 一个冰箱; 还有一个大人作为帮手。
Alright Squeaks, I’m going to pretend that our glaciers moved over some sandy areas, and some rocky areas, and even a big hill made of dirt.
好的，吱吱，我要假装我们的冰川经过一些充满沙土的地区，一些充满岩石地区，甚至一个由泥土组成的大山。
As it moved, it picked up bits of sand, rock, and dirt.
当冰川移动时，它携带了沙子、岩石和泥土。
We call this stuff glacial till.
我们称之为冰碛。
I’ll put a bit of glacial till in the bottom of our ice cube tray, and then fill the tray up the rest of the way with water.
我要在冰块托盘的底部放一点冰碛，然后在托盘的上方用水填满。
I’ll put this tray in the freezer, and wait for our mini-glaciers to freeze up!
我要把这个托盘放在冰箱里，等我们的小冰川结冰!
Well, while we wait, let’s make the land for the mini-glaciers to move over.
好吧，在我们等待的时候，让我们把陆地造出来，让小冰川移动过去。
We’ll make a big flat surface by rolling out some modelling clay.
我们将通过滚出一些建模粘土来做一个大的平面。
Let’s roll out a really big, flat rectangle.
让我们展开一个巨大扁平的矩形。
Alright!
好吧!
Let’s go check the icecube tray!
我们去看看冰块托盘吧!
Okay, our rectangle is ready, and our mini-glaciers are frozen!
好了，我们的矩形准备好了，微型冰川也冻住了!
Next, we’ll put the side of the mini-glacier with the dirt and rocks on the bottom, so they’re up against our modelling clay “Earth”.
接下来，我们将把迷你冰川的一边放上底部的泥土和岩石，所以这些构成了模型粘土“地球”。
Glaciers are really heavy, so when they move, there’s a lot of pressure, or force, on the Earth — in other words, they push down on the Earth pretty hard.
冰川非常重，所以当它们移动时，会给地球带来很大的压力，换句话说，它们给地球施加了很大的压力。
We can do the same thing here by pushing down on the mini-glacier really hard as we slowly scrape it across the clay.
我们也可以在这里做同样的事情，用非常大的力向下推迷你冰川，让它慢慢地摩擦黏土。
We’ll do this a few times…...and we’re ready.
我们将这样做几次...... 我们准备好了。
Let’s take a look and see what happened!
让我们看看发生了什么!
Whoa, the heavy pressure from our mini-glacier pressed the glacial till against our land, and left huge scratches.
来自小型冰川的巨大压力挤压冰川碛物，抵在地上，并留下了巨大的划痕。
Yeah, this looks just like what happens in real life!
是的，这看起来就像在现实生活中发生的事情!
When glaciers leave scratch marks on big rocks or in the ground, scientists call the marks glacial striations.
当冰川在大岩石或地面上留下划痕时，科学家称这种痕迹为冰川条纹。
But that’s not all glaciers can do: Sometimes, instead of scratches, glaciers can carve out a big chunk of land, leaving a big hole behind.
但这并不是冰川能做的全部:有时，冰川会凿出一大块陆地，留下一个大洞。
Rain can fill up the hole with water over time, and some of the glacier may even melt there.
随着时间的推移，雨水会填满这个洞，一些冰川甚至会在那里融化。
What do you think places where that happened might look like today, Squeaks?
吱吱，你认为那些曾经是冰川的地方今天看起来会是什么样子?
That’s right!
对!
Some of these big holes that glaciers make in the Earth become lakes!
有些冰川在地球上形成的大洞变成了湖泊!
They can be really big lakes, too, like the Great Lakes here in North America.
它们也可以是很大的湖泊，比如北美的五大湖。
Those giant lakes were carved out of the Earth by giant glaciers more than 10,000 years ago.
这些巨大的湖泊是一万多年前由巨大的冰川在地球上雕刻而成的。
Oh, what happened to the dirt that was dug up?
被挖出来的土呢?
Well, a few things can happen.
好吧，可能会发生一些事情。
For one thing, not all of the bits of sand, rock, and dirt carved out of the Earth by glaciers get stuck to the glacier forever.
首先，不是所有由冰川切割出来的沙子、岩石和泥土都永远粘在冰川上。
Sometimes, if the glacier sits in the same spot for a while, pieces of it will melt, and that sand and dirt we call glacial till will fall to the ground.
有时，如果冰川在同一地点停留一段时间，冰川碎片就会融化，我们称之为冰川碛的沙子和泥土就会落到地面上。
When this happens, it can leave big piles of sand and dirt!
当这种情况发生时，会留下成堆的沙子和泥土!
These big piles are called moraines, and eventually, they become a permanent part of the land.
这些巨大的堆积物被称为冰碛，最终，它们成为陆地上永久的一部分。
Trees and plants even grow on them!
树木和植物甚至在上面生长!
There are moraines all over, and they show us exactly where glaciers sat.
到处都是冰碛，这些冰碛可以告诉我们冰川的确切位置。
A big part of the Cape Cod area in Massachusetts is actually part of a big glacial moraine, where people now live on old glacial till!
马萨诸塞州科德角地区的很大一部分实际上是一个巨大的冰碛物的一部分，那里的人们现在生活在古老的冰碛物上!
In our model, we changed the land very quickly, but in real life, the changes happen very slowly, over hundreds or even thousands of years.
在我们的模型中，我们改变土地的速度非常快，但在现实生活中，这种改变发生得非常缓慢，要经过数百年甚至数千年。
Glaciers long ago left so many clues all over the world.
冰川很久以前就在世界各地留下了很多线索。
Look around, and maybe you’ll find some clues where you live!
四处看看，也许你会在你住的地方找到一些线索!
Maybe you can even find a lake made by a glacier.
也许你还能发现冰川形成的湖泊。
Explore your neighborhood, or even try your own mini-glacier experiment at home!
探索你的社区，甚至可以在家里尝试做迷你冰川实验!
And if you’d like to keep discovering new things with Squeaks, me, and all of our friends, make sure to hit subscribe.
如果你想和吱吱、我以及我们所有的朋友一起继续发现新事物，一定要点击订阅。
We’ll see you next time, here at The Fort.
我们下期见，沃斯堡等你。
