为什么早上所有东西上都有露水？

ABC 听播客。

ABC Listen.

你好。

Hello.

我叫尼兹。

My name is Nizh.

今天早上在《想象这》节目中，我醒得特别早。

And this morning on Imagine This, I'm awake really early.

外面还是黑的。

It's still dark outside.

我并不总是这么早起床，但今天我想看日出。

I don't always get up this early, but today, I wanted to see the sunrise.

很冷。

It's cold.

是的。

Yeah.

我能看见自己的呼气。

I can see my breath.

太阳升起来了。

The sun's coming up.

我听到鸟叫声了。

I can hear birds.

草都是湿的。

The grass is all wet.

有点滑。

It's a bit slippery.

为什么这么湿？

Why is it wet?

也许昨晚下雨了？

Maybe it rained last night?

没有。

No.

那是露水。

That's dew.

你知道吗？

Well, do you know what?

我们收到过一个关于露水的问题。

We've had a question about dew.

嗨。

Hi.

我叫爱德华，七岁。

My name's Edward and I'm seven years old.

我想知道为什么早上所有东西上都有露水？

And I would like to know why is the dew on everything in the morning?

你觉得露水是怎么来的？

How do you think the dew gets there?

是雨水带来的。

Gets there with rain.

雨水让它落下来。

The rain makes it drop down.

可能是水蒸发后形成的。

From water evaporating, maybe.

在非常寒冷的地方。

In cold, cold places.

从排水管里来的。

From the drains.

也许吧。

Maybe.

幸运的是，我知道该向谁请教你的问题。

Thankfully, I do know who to ask about you.

内特·伯恩。

Nate Byrne.

我认识他。

I know him.

他是个气象播报员。

He's a weatherman.

我认为他是天气预报员。

He's a weather forecaster, I think.

是的。

Yep.

内特是个气象学家。

Nate is a meteorologist.

那就是一位天气科学家。

That's a weather scientist.

而你的一切都和天气有关。

And you is all to do with weather.

我们去问问内特吧。

Let's ask Nate.

好主意。

Great idea.

等一下，我叫他接电话。

Hold on a sec and I'll get him on the blower.

你好。

Hello.

我是内特。

Nate speaking.

最好是有天气紧急情况。

This better be a weather emergency.

我正忙着呢。

I'm very busy.

内特？

Nate?

嘿。

Hey.

是我，尼奇。

It's Nidge.

Nidge，我最喜爱的物理学家朋友。

Nidge, my favorite physicist friend.

你有空过来回答一个关于露水的科学问题吗？

Any chance you're free to come and answer a science question about dew?

给我一秒钟。

Give me one second.

嘿，米奇。

Hey, Mitch.

嗨，大家好。

Hi, everyone.

真快啊。

That was fast.

Nate，你来得真快。

Nate, you got here so quickly.

你知道，我从不会错过谈论天气的机会。

You know I'd never pass up the opportunity to talk about weather.

是的。

Yeah.

我知道。

I know.

我们一直在想

We were wondering

为什么早上所有东西上都有露水？

Why is there dew on everything in the morning?

它们是从哪里来的？

Where did they come from?

露水其实一天中的任何时候都可能发生，但需要恰好合适的条件，而这通常发生在清晨。

Well, dew can happen at any time of day, but the conditions have to be just right, and that tends to be early in the morning.

露水是由什么组成的？

What's dew made from?

是这种水吗？

Is it this water?

是的。

Yep.

露水就是水，但一滴水是由数十亿个微小的水分子组成的。

Dew is just water, but a single drop of water is made of billions and billions of tiny little water molecules.

分子。

Molecules.

它们太小了，你根本看不到。

They are so small, you can't see them.

它们一直存在于我们周围的空气中。

They're in the air around us all the time.

空气中也有水？

There's water in the air?

但我没必要穿潜水服到处走。

But I don't need a scuba suit to get around.

幸好不用。

Thankfully not.

那是因为水是一种非常特别的物质。

That's because water is very special stuff.

它有三种形态。

It can come in three forms.

它可以是固态

It can either be a solid

墙壁和结冰的水。

Walls and water as ice.

北极的冰。

Ice ice in the North Pole.

是的。

Uh-huh.

它也可以是液态

It can be a liquid

在我的淋浴间里。

In my shower.

河流、溪流、海洋，就像从水池里喝水一样。

River, stream, ocean from a pool, like when you drink water.

没错。

Exactly.

或者水可以是气态。

Or water can be a gas.

就像放屁一样。

Like farts.

不是。

No.

我不是。

I'm not.

放屁。

Fart.

像蒸汽吗？

Like steam?

不是

Not

完全不是。

quite.

蒸汽在技术上仍然是一种液体，因为它由足够多的水分子聚集在一起形成微小的水滴。

Steam is technically still a liquid because it's made up of enough water molecules clinging together to make tiny water droplets.

蒸汽来自火车。

Steam is come from trains.

当我的父母在炉子上做饭，锅里冒出蒸汽的时候。

When my parents are cooking on the stove and the steam comes out of the pots.

是的。

Yeah.

但当水是气态时，它是看不见的。

But when water is a gas, it's invisible.

我们称之为水蒸气，它一直弥漫在我们周围的空气中。

We call it water vapor, and that's what's floating around us in the air all the time.

这有点奇怪，但也很正常。

It's sort of weird, but also normal.

哇。

Wow.

露水是什么？

What's dew?

要理解为什么早晨 everything 都会沾上露水，我们可以化身成一个水分子，跟随它的旅程。

To see why dew gets on everything in the morning, we could hop into a water molecule and follow the journey.

你愿意吗？

You game?

是的。

Yeah.

等一下。

Hang on.

你想把我们所有人都塞进一个微小得不能再小的水分子里面吗？

You wanna fit all of us in just one teensy weensy miniscule water molecule?

我们必须发挥想象力。

We have to use our imagination.

当然。

Of course.

抱歉。

Sorry.

我忘了。

I forgot.

好吧。

Alrighty.

三、二、一。

Three, two, one.

我们开始了。

Here we go.

它们漂浮在空气中。

They're floating in the air.

往下看。

Look down.

哇哦。

Woah.

地面离我们有十亿英里远。

The ground is a billion miles away.

嘿。

Hey.

又一个水分子粘到了艾伦身上。

Another water molecule just stuck to Alan.

水分子彼此相爱。

Water molecules love each other.

当它们相遇时，会紧紧相依。

When they meet up, they hang on really tight.

哦，越过这个。

Oh, past this.

然后我就得一直待着，直到你被严重狙击。

And then I'm stuck till you're highly sniped.

哇哦。

Woah.

那是三个水分子。

That's three water molecules.

我们是不是要变成一滴水了？

Are we becoming a water drop?

抱歉，Nidge。

Sorry, Nidge.

三个分子可成不了水滴。

Three molecules does not a droplet make.

我觉得我们还差几十亿个呢。

We are at least a few billion short, I think.

哇哦。

Woah.

看看我们周围。

Look around us.

我能看到水分子漂浮在各处。

I can see water molecules floating everywhere.

嘿。

Hey.

嘿。

Hey.

它们是什么？

What are they?

空气分子。

Air molecules.

和水一样，空气也是由微小的粒子组成的。

Just like water, air is made up of tiny little bits.

看。

Look.

那边有一部分氮气和鸭子。

Over there, there's a bit of nitrogen and duck.

小心二氧化碳。

Mind the carbon dioxide.

哇哦。

Woah.

空气中有很多东西。

Air's got a lot of stuff in it.

没错。

That's right.

空气分子的运动和行为会随着温度变化而改变。

The way air molecules move and behave changes at different temperatures.

这对水分子有很大影响。

This has a big impact on water molecules.

让我给你展示一下。

Let me show you.

但首先，我需要把时钟快进到一天中最热的时候。

But first, I'm going to need to fast forward our clocks to the warmest time of the day.

等等，大家。

Hold on, everyone.

我们要出发了。

We're going for a ride.

哇哦。

Woah.

哇哦。

Woah.

哇哦。

Woah.

太阳移动得真远。

The sun is moving really far.

看起来那只蜗牛超速了。

It looks like that snail is breaking the speed limit.

我们正在穿越时间。

We're zooming through time.

现在阳光明媚。

It's sunny now.

希望你戴着帽子。

Hope you're wearing your hat.

现在是正午时分。

It's the middle of the day.

外面发生什么事了？

What's happening out there?

空气分子正在狂乱运动。

The air molecules are going wild.

当空气变暖时，微小的空气分子会变得兴奋。

When the air warms up, the tiny air molecules get excited.

它们真的开始撞来撞去，因为根本无法抑制自己的能量。

They literally start bouncing off the walls because they can't contain their energy.

妈妈说我不时就会这样。

Mom says I do that sometimes.

当你兴奋的时候，很难静坐不动。

It is hard to sit still when you're excited.

嘿。

Hey.

空气分子刚刚撞到我们了。

The air molecule just hit us.

它把粘在我们身上的朋友们撞开了。

It knocked off our friends that it stuck to us.

我们又变回了单个分子。

We're back to being just a single molecule.

是的。

Yes.

空气分子在高温下快速穿梭，撞击水分子并将其分解。

The air molecules zip around in the heat and they bump into the water molecules and break them up.

尽管水分子彼此想紧紧依偎，但空气不断介入，这种不断的碰撞和推挤正是让水分子保持在空中的原因。

Even though the water wants to keep holding on to each other, the air keeps getting in the way, and all of that jostling and bumping is what keeps water molecules up in the air.

看。

Look.

现在有更多分子了。

There's more molecules now.

它们是从哪里来的？

Where did they come from?

暖空气可以携带更多的分子。

Warm air can carry more of them.

这有点像杂耍。

It's a bit like juggling.

你的手动得越快，就能让更多的球保持在空中。

The faster your hands move, the more balls you can keep up in the air.

温度越高的空气，分子运动就越快。

Warmer air equals faster molecules.

哦，这就像嬉皮士飞起来一样。

Oh, it's like hippie uppie.

嘿。

Hey.

出去吧，氧气。

Get out of it, oxygen.

这些水都是从哪儿来的？

Where's all this water coming from?

嗯，到处都是。

Well, all over.

地上的水洼、河流、湖泊、游泳池、晾着的湿衣服，甚至你皮肤上的汗水。

Puddles on the ground, rivers, lakes, swimming pools, wet washing on the line, and and even the sweat on your skin.

这叫做蒸发。

It's called evaporation.

我开始觉得又热又黏了。

I'm starting to feel all hot and sticky.

真潮湿。

So humid.

是的。

Yeah.

空气感觉黏腻，是因为空气中充满了被空气分子不断搅动的水分子。

The air feels sticky because it's full of water being juggled around by the air molecules.

太热了。

Too hot.

太热了。

Too hot.

我不再想要一堆东西围着我了。

I don't want a batch around anymore.

没问题。

No problem.

我可以帮上忙。

I can help with that.

让我们把时钟拨到一天中更冷的时段。

Let's wind our clocks forward to a much colder part of the day.

就在日出之前，我想。

Just before sunrise, I reckon.

我们将看到这些忙碌的分子会发生什么。

We'll see what happens to all these busy molecules.

哇。

Woah.

太阳正在落山。

The sun's going down.

我见过最快的日落。

Fastest sunset I've ever seen.

街灯亮起来了。

The street lights are coming on.

我想我们刚刚过了我的睡觉时间。

I think we've just gone past my bedtime.

现在确实挺冷的。

Well, it is pretty chilly now.

我快冻僵了。

I'm freezing.

而且还在往下掉。

And falling.

气温在下降，我们也在往下掉。

The air temperature's dropping, and so are we.

内特，为什么那个水分子在往下落？

Nate, why is that water molecule falling down?

这是雨吗？

Is this rain?

不是。

No.

我们还太小，算不上雨，但这正是形成露水的关键。

We're still too small to be rain, but this is the key to making dew.

抓紧了。

Hang on tight.

一切都慢下来了。

Everything's slowed down.

嘿。

Hey.

其他所有水分子都挤到我们周围了。

All the other water molecules are crowding in around us.

我感觉被挤扁了。

I'm feeling squished.

让一让，拜托。

Move over, please.

它们都围在我们周围。

They're all around around us.

我们。

Us.

在冷空气中，分子的运动变得不那么剧烈了。

In cold air, molecules stop moving around as much.

空气分子没有足够的能量来分解水滴了。

The air molecules don't have enough energy to break up the water droplets anymore.

它们无法再托住水滴。

They can't hold them up.

就像水分子在寒冷中紧紧依偎在一起。

It's like the water molecules are huddling together in the cold.

是的。

Yeah.

水分子喜欢聚在一起。

Water molecules love getting together.

哦，我们挤得可真紧。

Oh, we're pretty tightly packed.

来吧。

Come on.

你能腾点空间吗？

Can you make some room, please?

爸爸，求你了？

Dad, please?

他们正和我们一起过来。

They're joining us with us.

发生什么事了？

What happened?

我们在哪儿？

Where are we?

足够的水分子聚集在一起了。

Enough water molecules joined up.

它们让水蒸气（气体）重新变回了液态。

They've made them turn from water vapor, a gas, back into a liquid.

在一片草叶上。

On a plate of grass.

你去哪儿了？

Where did you?

嗯。

Mhmm.

水需要附着在某种物体上才能形成露水，所以你通常会在草地或过夜留在户外的物品上看到它。

The water needs something to grab onto to become dew, so you'll usually spot it on grass or stuff that's been left outside overnight.

我的自行车上有水滴。

I got drops on my bike.

我看到我邻居的房子上也有，那里是公交站。

I saw one on my neighbor's house to sit at the bus stop.

蹦床上总是有。

A trampoline always has it.

就是这样。

That's it.

我们把这种过程叫做凝结。

We call this process condensation.

这正好是蒸发的反过程，它发生在这里是因为地面是夜晚最先变冷的地方，而且周围有东西能让水分子附着。

It's just the opposite of evaporation, and it happens down here because the ground is the first place to get cold at night, and there's stuff around for the water to grab onto.

干杯。

Cheers.

大量的水分子在互相依偎。

Lot of water molecules cuddling.

是的。

Yeah.

再次爱你。

Love you again.

这感觉真好。

This feels great.

我们是分子伙伴，不是放屁帮。

We're Molecule Mates, not the gassy gang.

我们现在进入液态领域了，但露水不会持续太久。

We're in the liquid leagues now, but dew doesn't last for long.

发生什么事了？

What's going on?

水分子为什么在抖动？

Why are the water molecules jiggling?

哦，它们在变热。

Oh, they're heating up.

它们在获得能量。

They're getting energy.

是的。

Yep.

V射线。

The v ray.

水分子又飞起来了。

The water molecules are flying again.

它们在蒸发。

They're evaporating.

记得吗？

Remember?

这是凝结的反过程。

It's the opposite of condensing.

所以太阳的热量正在注入能量，空气再次加速，开始将那些水分子撞离，使它们从液态变回气态。

So the heat from the sun is adding its energy, the air is speeding up again, starting to knock off those water molecules, turning them back from a liquid into a gas.

这对我们意味着什么？

What does that mean for us?

我们又飞起来了。

We're flying again.

等等。

Hang on.

我们不会停下。

We're not stopping.

哎呀。

Uh-oh.

尼格，我们已经升得挺高了。

Nige, we're getting pretty high up.

内特，我们现在飞过树顶了。

Nate, pass the treetops now.

那是只鸟吗？

Is that a bird?

是飞机吗？

Is it a plane?

记住，空气中到处都有水，但随着我们升高，空气会变冷。

Remember, there's water all through the air, but as we go higher, the air gets colder.

所以这意味着水分子会聚集在一起，再次变成露水吗？

So that means the water molecules will stick together and will become become dew again?

然后落在草地上？

And land on grass?

这里没有草，但这粒灰尘看起来挺合适的。

No grass up here, but this speck of dust looks pretty good.

灰尘？

Dust?

是的。

Yeah.

天空中漂浮着大量的微小灰尘。

There's lots of microscopic dust floating around in the sky.

我们可以凝结在上面。

We could condense on that.

嘿。

Hey.

更多的水分子又粘到我们身上了。

More water molecules are sticking to us again.

欢迎回来。

Welcome back.

我们又在重新凝结了吗？

Are we redoifying?

那是个词吗？

Is that even a word?

记住，水喜欢聚在一起。

Remember, water loves getting together.

当无形的水蒸气附着在高空的尘埃上，越来越多的分子聚集粘连在一起，它们会变得越来越大，最终变成你能看到的东西。

When the invisible water vapor attaches on to dust high in the sky and more and more of the molecules come and cling together, they grow bigger and bigger and turn into something you can see.

那就是云。

It's clouds.

云。

Clouds.

云。

Clouds.

我们正在变成一朵云。

We're turning into a cloud.

它们就像棉花糖和蓬松的碎片。

They're like a marshmallow and fluffy bits.

所以云就像是天上的露水吗？

So clouds are sort of like, sky dew?

我从来没这么想过，但没错，我想是这样的。

I've never thought of it that way, but, yeah, I suppose so.

露水和云都是凝结现象。

Dew and clouds are both condensation.

可见的水蒸气分子聚集在一起，转变成我们能看到的液体。

The molecules in visible water vapor joining together and changing into a liquid we can see.

云是液体吗？

Clouds are liquid?

是的。

Yep.

你知道当它们变得太重时会发生什么吗？

And you know what happens when they get too heavy.

雨滴。

Raindrops.

它们会下雨。

They rain.

你说对了。

You got it.

我们这些天气爱好者称之为降水。

Us weather lovers call it precipitation.

哦，不。

Oh, no.

这片云看起来快要爆裂了。

This cloud is looking like it's about to burst.

哦，这声音让我想起来。

Oh, that sound reminds me.

我得赶紧去工作室告诉大家即将有雨，让他们别忘了带伞。

I've got to get to the studio and tell everyone that there's wet weather on the way so they don't forget their umbrellas.

再见，大家。

Bye, everybody.

我待会儿见，内特。

I'll see you, Nate.

谢谢。

Thank you.

再见。

Bye.

至于我们其他人，让我们带着新的水分子朋友回到地球吧。

As for the rest of us, let's come back to Earth with our new water molecule friends.

让我们下场雨吧。

Let's make it rain.

你准备好了吗？

Are you ready?

我们开始吧。

Here we go.

所以，爱德华，露水是当空气中的水汽在地面凝结时形成的。

So, Edward, dew forms when water in the air collects on the ground.

空气中充满了各种不同的分子

The air is full of lots of different molecules

氮气、氧气、二氧化碳。

Nitrogen, oxygen, carbon dioxide.

还有水分子作为看不见的气体在我们周围飘荡。

And water molecules swirling all around us as an invisible gas.

你看不到它。

You can't see it.

当温度较高时，空气分子因具有大量能量而不断碰撞，使水分子彼此分离。

When it's warm, the air molecules bounce around with lots of energy and keep the water molecules apart.

它们开心地玩耍。

They play to be happy.

当温度下降时，它们的运动变慢，空气分子再也无法将水分子分开了。

When things cool down, they slow down, and the air molecules can't keep the water molecules apart anymore.

我喜欢拿着蜡烛。

I like holding candles.