节目资讯
刊物:空中英語教室
日期:2012-04-11
难易度:Low
关键字:iceberg, more (to somebody/something) than meets the eye, melt, bubble
OK. I hope you had a great break.
Welcome back.
Did you know that not every piece of ice in the ocean counts as an iceberg?
Of course, there are also things called bergy bits, growlers and ice islands.
You can learn more about these in the Information Bar at the top of page 24.
Right now let's find out how icebergs are born on line 9.
Secrets of the Iceberg.
Icebergs begin forming when layers of snow fall year after year without melting.
The snow is pressed together into large blocks of ice called glaciers.
When chunks of ice break off of these glaciers, icebergs are born.
In Greenland alone, about 40,000 icebergs are formed each year.
Since they began as snow, icebergs are made of fresh water, not salty ocean
water.
Tiny bubbles of air inside the ice give them their white color.
(Music).
Well, icebergs they actually begin forming when layers of snow fall year after
year without melting.
And so snow falls year after year, and that builds up.
That's right.
Now if you live in a warm climate, if you've never been to a place with a lot of
snow, this might be hard to imagine.
But Brandon, where I live, we... the snow does melt.
But we do get a lot of snow; and in the high mountains, it doesn't always melt.
And if it's cold enough, this can happen.
That's right.
And it builds up over time.
And that's why the ice is so big.
It's massive pieces of ice because it does not melt.
Now when something "melts," it goes from a solid state to a soft state.
You can think of an ice cube, if you take it out of the freezer and put it in
the sink or on the counter, it will melt.
That's right, it melts. It goes from solid to a liquid.
Well... so we're talking about these as layers.
So if you think about a year, maybe one winter we have a whole lot of snow that
comes down and only some of it melts.
But all year long there's still snow on the ground.
Well, the next time it snows, the air is going to be a little bit different.
So the snow starts piling up, layer after layer, and never melting.
So let's see what happens next.
Well, the snow is actually pressed together into large blocks of ice called
glaciers.
So the snow is pressed together because it's falling and piling up.
It kind of just compacts and presses together.
That's right.
So no one's out there actually pushing the ice together, no one is pressing it.
But through nature, just through the wind and the different falling temperatures
and everything that is involved in weather, it pushes them together and forms
glaciers.
That's right.
And glaciers are just large areas of ice.
And so this is how these icebergs form, how they come about.
That's right. Well, we've talked about glaciers here before.
And we know that... glaciers are giant rivers of ice that are moving very, very
slowly towards the ocean.
Well, when it reaches the ocean, something happens.
That's right.
We see when chunks of ice break off of these glaciers, that's actually when the
icebergs are born.
And so a chunk of something is a big portion breaks off, and then that is an
iceberg.
That's right. Now if you want to use your... another example of chunking, maybe
you have a loaf of bread,
and you take your hand and grab a handful of the bread and tear it off, you have
a chunk of bread.
And that's what happens with the glaciers as well.
It's as if you take... your hand and pull off a giant piece.
And those have to be giant to make the icebergs the right size.
That's right.
And actually we see in Greenland alone, about 40,000 icebergs are formed each
year.
And this is a good statistic to know.
It gives us an idea about how many icebergs form there.
40,000 per year, Kaylah.
That's in Greenland.
And you can see a map of Greenland in your Studio Classroom magazine.
But that's only in Greenland.
That's not counting all the other countries that are in the northern hemisphere,
far enough north to be creating icebergs every year.
So Brandon, there's a lot of icebergs.
A lot.
And many other countries, as you said, there are icebergs.
And since they began as snow, icebergs, well, they are made of fresh water, not
salty ocean water.
And again, this is not something maybe that we would always think of.
But because it's falling from the snow, it is actually fresh water and not the
salty ocean water.
Yeah. I would have thought they were salty because they're in the ocean.
But you're right, because of the snow, snow does not fall salty, then it is, in
fact, fresh water now floating in salty ocean water.
So if you're thirsty and you have something to warm up the ice, it's fresh.
You can drink it.
That's pretty nice.
I probably wouldn't think it, though, Brandon.
That doesn't sound very healthy.
True. Well, tiny bubbles of air inside the ice give them their white color.
What's a bubble, Kaylah?
Well, a "bubble" is a small sphere of air with a light film on the outside.
Maybe you think of blowing bubbles as a kid.
You have soap, and you blow bubbles into the air.
It makes those cute, little floating dots and...
But these are not floating, and they're in a film.
Instead, it's water; it's... the air is trapped in the water.
That's true.
So we've learned a lot already about icebergs, and maybe you're feeling a little
cold.
I'm a little chilly, Kaylah, just talking about icebergs and how big they are,
and it makes me want to go put a warm coat on.
Oh. Well, I'm sorry about that, Brandon.
OK. I... I want to go back to this talking about their color because, you know,
it makes sense when we think about water, we think, well, water is clear.
So when we have ice in our cups, our ice cubes intend to be pretty clear.
But icebergs are, in fact, white on the outside, on the top surface.
So I never knew this and find it very interesting.
It is very interesting.
We're being very specific here about the icebergs, and even what color they are.
And we're going to learn more about their colors.
Remember we talked about we have to look beyond just the surface of the iceberg,
we have to go deep down?
And sometimes because of that, the colors can actually change.
That's right.
Well, Brandon, have you ever seen videos of icebergs being formed off of
glaciers?
I have. And that is amazing.
I think you can even hear the cracking sound.
It's cracking and the chunks just floating off.
And that is an amazing sight for sure.
That's right.
You can look that up on the Internet.
You can also see it on... the Lonely Planet tapes have some very incredible
footage of a glacier making these chunks that become icebergs.
It's loud, it's dangerous, but it's very interesting.
Well, we got more to talk about icebergs tomorrow.
But for now, let's watch today's skit.
Professor, this place is freezing!
What are you doing here?
I'm studying the secrets of icebergs.
The secrets of icebergs?
Shh. Yes, the secrets of icebergs.
Why do you want to study large blocks of ice?
In truth there's far more to icebergs than meets the eye.
More than meets the eye?
Yes. You can only see about 10 percent of an iceberg.
So only 10 percent meets the eye?
Where is the rest of it?
It lies hidden beneath the water.
Oh. Is that why ships crash into them?
Yes, indeed.
Oh... Where do icebergs come from, anyway?
Icebergs form when layers of snow fall years the year without melting.
Oh! They come from snow?
Yes. The snow is pressed together into large blocks called...
Giant ice cubes!
No, no, no... called glaciers.
When chunks of ice break off of the glaciers, icebergs are born.
Oh. So that's where icebergs come from.
Since they come from snow, they are made of fresh water, not salty ocean water.
Oh, is that's why icebergs are white, because they're made of snow?
Actually, tiny bubbles of air inside give them their white color.
Bubbles of air make icebergs white.
Yes. It's one of the secrets of icebergs. Shh.
Shh.
(Music).
Hi, everyone. I'm Michelle.
(Chinese).
And we have to say goodbye now.
Make sure you come back tomorrow. See you.
The English word "iceberg" came into use during the late 1700's.
Before that, people called these giant floating islands of ice "sea-hills."
Friends,
be sure to log on to Studio Classroom's website and take advantage of our
worksheets.
The activity for this lesson is a quick review of some useful grammer patterns.
Check it out and bring your English to a new level.
OK. Be sure to join us tomorrow as we look at more Secrets of the Iceberg.
Until then, have a great day.