云概念的简单理解（whatisa）

云概念的简单理解（whatisa）Where do clouds come from?云回收Each droplet is made of many water molecules stuck together around a tiny speck of dust or salt.How small are cloud droplets?If you filled a shoe box with could.you would have more than 100 billion cloud drops.每个液滴都是由许多水分子组成的 这些分子粘在一起 围绕着一小片灰尘或盐。云滴有多小？如果你把鞋盒装满了云， 你就会有超过1000亿的云滴Clouds Recycle

Clouds are floating water

云是漂浮的水

Clouds are made for water.But they aren't vapor individual molecules of water flying around as a gas.Clouds are made of itsy-bitsy water droplets.

云是为水而造的。但它们不是蒸汽 个别的水分子作为气体飞来飞去。云是由被小的水滴组成的。

Each droplet is made of many water molecules stuck together around a tiny speck of dust or salt.How small are cloud droplets?If you filled a shoe box with could.you would have more than 100 billion cloud drops.

每个液滴都是由许多水分子组成的 这些分子粘在一起 围绕着一小片灰尘或盐。云滴有多小？如果你把鞋盒装满了云， 你就会有超过1000亿的云滴

Clouds Recycle

云回收

Where do clouds come from?

云是从哪里来的？

As the sound warms the Earth water evaporates from lakes rivers oceans and the leaves of plants-and from you when you get sweaty.when water evaporates it makes vapor individual molecules floating around.

当声音温暖地球时 水从湖泊、河流、海洋和植物的叶子中蒸发 当你出汗的时候 当你出汗的时候 水就会产生蒸汽 单个分子漂浮在周围。

Air carries the water vapor around.As warm air rises it takes water vapor from the surface with it.

空气把水蒸气带来。随着暖空气的上升 它带走了表面的水汽。

Air cools as it rises.And when cooling water molecules meet a speck of salt or dust they condense or stick together.A droplet forms.When this happens over and over millions and billions of times-a cloud is born.

空气上升时冷却。而当冷却水分子遇到一点盐或灰尘时 它们会凝结 或者粘在一起。液滴形成。当这种情况反复发生时 数百万和数十亿次的云就诞生了。

Eventually the cloud droplets clump together and fall as rain or snow refilling rivers and oceans and nourishing plants.And the cycle starts all over again.

最终 云滴聚集在一起 像雨雪一样落下 给河流和海洋加满 滋养植物。而这个循环又重新开始了。

Clouds constantly recycle Earth's water.In fact the water that falls on you from a cloud is the same water that dinosaurs once drank.

云不断回收地球的水。事实上 从云中落在你身上的水和恐龙曾经喝过的水是一样的。

Clouds Are heavy云很重

Clouds look light and fluffy but they hold a lot of water And water is heavy the water in an average cotton-ball cloud weighs as mush as a whole herd of elephants.A big storm cloud might hold two billion pounds of water!So how can they float?

云看起来又轻又蓬松 但它们容纳了大量的水 水很重 普通棉球云中的水的重量和整群大象一样大。一个大的风暴云可能会容纳20亿英镑的水!那么它们怎么会漂浮呢？

First all that water is spread out over a pretty big area.Even if the whole cloud weighs a lot each little bit of it is pretty light.

首先 所有的水都分散在一个相当大的区域。即使整个云的重量很大 它的每一点都是相当轻的。

Next the water droplets inside the cloud are so tiny that they float easily.Each drop is so light that it has a hard time pushing aside the air under it-so the air holds it up.

接下来 云中的水滴非常小 很容易漂浮。每一滴都是如此的轻 以至于它很难把下面的空气推开 所以空气把它支撑起来。

Most clouds form in places where warm damp air rises up into colder air.

大多数云形成于温暖潮湿的空气上升到较冷的空气中的地方。

Warm air rises and that warm rising air pushes the cloud up too.暖空气上升 暖升的空气也把云推了起来。

And there's one last surprising way clouds stay afloat:

还有最后一个令人惊讶的方式云保持漂浮

they heat themselves from within.When water molecules clump together to make a droplet they transfer some of their motion energy to the air around them.This warms the air inside the cloud-so it keeps rising.

他们从内部加热自己。当水分子聚集在一起形成一小滴时，它们就会将部分运动能量传递给周围的空气。这使得云中的空气变热，所以它不断上升。

Of course most clouds do eventually fall-that's what we call rain.当然，大部分的云最终还是会落下，这就是我们所说的雨。

They're never still他们从来没停过

All that water can't stay up forever.As the cloud rise into cooler air droplets form bigger and bigger clumps.When the drops get heavy enough they fall as rain or snow or hail .Most rain actually starts out as ice high up in a cloud it melts when it hits the warmer air closer to the ground.

那些水不可能永远待在上面。当云层上升到较冷的空气中时，水滴形成越来越大的团块。当雨滴变得足够沉重时，它们就会变成雨、雪或冰雹。事实上，大多数雨都是以冰的形式出现的，在云上，当雨落在靠近地面的暖空气中时就会融化。

All the time warmer air is trying to rise inside the cloud while cold.

一直以来，在寒冷的天气里，温暖的空气试图在云中升起。

itsy-bitsy 小小的