英国皇家科学院圣诞讲座2020行星地球（2020）

一万两千多年以来
For over 12,000 years,
生活在地球上的人类和其它无数的物种
we and millions of other species on the planet have benefited
均受益于能带来稳定气候
from an atmosphere which has given us a stable climate
及生命所需的大气层
and life-giving air.
但我们是否有停下来 对大气层
But how often do we stop to think
以及每日呼吸着的空气进行思考呢
about our atmosphere and the air that we breathe?
行星地球
用户指南
第三部分 大气
大家好 我是塔拉·希内博士 一名环境学家
Hi, I'm Dr Tara Shine and I'm an environmental scientist.
欢迎来到今年圣诞讲座的最后一课
Welcome to the last of this year's Christmas lectures.
我们先是与克里斯一起了解陆地
We started by looking at the Earth with Chris
接着与海伦一同探索海洋
and then we explored the oceans with Helen.
今天我们将去看看大气层
And today, we're going to look at
了解它是怎样运作的
our own atmosphere, how it works,
人类对它有什么影响 以及该如何保护它
the effect we're having on it, and what we can do to protect it.
这位是安迪 爱丽丝·希克森的潜水安全员
This is Andy. Andy is Alice Hickson's safety diver.
如大家所见 爱丽丝正屏住呼吸
And as you can see, Alice is submerged under the water
沉入水中
and she's holding her breath.
作为一名自♥由♥潜水员 爱丽丝常年这样训练
Alice has trained to do this for many years as a freediver,
请勿在家模仿
so please do not try this at home.
爱丽丝已经屏息待在水下
As you can see, Alice has already been underwater
超过一分半的时间了
for more than a minute and a half, holding her breath.
真希望我也能做到
I wish I could do what Alice is doing.
我热爱大海 我喜欢游泳
I love the sea, I love swimming, and I get really frustrated
当我不能长时间屏住呼吸
when I'm not able to hold my breath long enough
去与鱼蟹嬉戏
to chase that crab or that fish,
因为缺氧而被迫回到水面时 会变得无比沮丧
and I'm forced back to the surface by the need to breathe.
这也是我学水肺潜水的原因
That's why I learned to scuba dive.
当我潜水时 会用上这样一个罐子
When I scuba dive, I use a tank like this one.
许多人会以为这个罐子里装的是氧气
Now, lots of people think this tank is filled with oxygen.
甚至为其取名氧气罐
They might even call it an oxygen tank,
但纯氧在深海对人体是有害的
but pure oxygen at depth would be toxic to my body.
实际上 这个罐子里装的是压缩空气
Instead, this tank is filled with compressed air.
那么我们呼吸的空气中有些什么呢
But what is in the air that we breathe?
也许正是因为我们看不见它
Perhaps because we can't see it
我们才会把它视作当然
that's why we take it for granted.
如果我对空气进行冷却呢
But what if I cooled this air down?
我是说 如果我将空气大幅冷却
And by that I mean, what if I cooled it down "a lot"
到达零下两百摄氏度会怎样
to minus 200 degrees Celsius?
在那样的温度下
At that temperature,
我们将能看见被液化的气体
the gas becomes liquid and we can see it.
我现在把它倒进这个容器中
So what I'm going to do is pour this into this container.
大家能看见 这是一种透明液体 氮
As you can see, it's a clear liquid. This is nitrogen,
液氮 大气中百分之七十八的成分为氮气
liquid nitrogen, and nitrogen makes up 78% of our atmosphere.
这个容器差不多装满了
I'm filling that almost up to the top,
冒出来到处都是
it's bubbling all over the place.
大气中不仅有氮气
So there's not just nitrogen in the atmosphere.
这个红色烧瓶里的是什么呢
What might be in this red flask?
让我们倒出来看看 是很漂亮的蓝色
Let's pour that out. It's a beautiful blue colour.
氧 液氧 赋予人类生命的氧气
This is oxygen, liquid oxygen, that life-giving gas.
氧气占据大气成分的百分之二十一
21% of our atmosphere is made up of oxygen.
还有剩下的百分之一 是由微量气体组成
So that leaves 1%, and 1% is made up of trace gases
例如 氩气 甲烷
like argon, methane.
还有这个 占据大气0.04%的成分
And this here, 0.04% of our atmosphere
二氧化碳
is made up of carbon dioxide.
此刻爱丽丝体内正在累积的
And it is this same gas, carbon dioxide, that's building up
促使她想要呼吸的正是这种气体
in Alice's body right now and making her want to breathe.
让我们看看爱丽丝怎么样了
So let's go check on Alice.
专业技术 请勿模仿
爱丽丝待在水下的时间已经
Wow, look, Alice has already been underwater
长达三分五十秒了
for three minutes, 50 seconds.
之前说过 她是受过专项训练的
As I've told you, she is trained to do this.
爱丽丝是英国的世界女子自♥由♥潜水冠军
Alice is the UK World Champion Women Freediver.
现在让我们把她叫起来谈谈她做的事情
But let's get her up now to talk to her about what she's doing
以及她是怎么做到的 安迪 你能拍一下她吗
and how she does it. Andy, can you give her a tap for me?
她已经屏息四分十秒了
So she's at four minutes and ten seconds.
太厉害了
Amazing.
爱丽丝 四分十秒 你是怎么做到的
Alice! Four minutes and ten seconds. I don't know how you do it.
真希望我也能做到
I wish I could do it!
太不可思议了 你现在感觉怎么样
That's incredible. How do you feel?
-挺好的 -没错 你好像不费吹灰之力
- I'm all right. - You're all right. You're just, no bother.
跟我说说 你是怎么做的
Tell me, how do you do it?
你是如何抑制住呼吸的冲动的呢
How do you, how do you resist the urge to breathe?
硬撑
Stubbornness?
-硬撑 -还有大量的练习
- Stubbornness. - And lots of practice,
训练自己身体
and training your body to get used
对二氧化碳和乳酸累积的
to the tolerance of the build-up of carbon, carbon dioxide
耐受能力 对 就是练
and lactic acid and, yeah, just lots of practice.
需要放松自己吗
Do you also need to be very relaxed?
是的 既需要生理上的放松
Yeah, it's as much a psychological thing
也需要心理上的放松
as it is a physical thing.
你保持的纪录是什么
What kind of records do you hold?
英国所有的静态闭气纪录 以及
All the British pool records and then the depth records,
无蹼下潜的深度纪录 也就是不戴脚蹼
so, for no fins, which is swimming
尽可能游到深处 有点像蛙泳
as deep as you can without fins, a bit like breaststroke,
我能在没有脚蹼的情况下潜至水下六十米
so I can swim 60 metres deep under the water
并返回
and back without fins,
我静态闭气的正式纪录是六分五十八秒
and then I can hold my breath for 6.58 is the official record.
在你潜水前并没有
And you didn't do a whole lot of like, kind of
像我这样
stuff before you went down.
过度呼吸并不是一件好事 这样会更危险
Hyperventilating makes it dangerous. That's not a good thing.
-你更需要的是放松 -谢谢你 爱丽丝
- It's more about being relaxed. - Thank you, Alice.
太棒了
That was just amazing.
真不敢相信你在水下待了四分钟之久
I can't believe you stayed under for four minutes.
-谢谢你 -谢谢
- Thank you. - Thank you.
二氧化碳是人体制♥造♥能量和进行呼吸时
Carbon dioxide is a waste product from the production of energy
产生的废物
in our bodies and from respiration.
我们吸入氧气 让它与来自食物的葡萄糖
So, we breathe in oxygen and we use that along with glucose
相互作用 产生能量
from our food to produce energy.
而这一过程中产生的废物
And the waste products from that process
就是水和二氧化碳
are water and carbon dioxide.
欢迎各位在线观众
Hello and welcome to our virtual audience.
很高兴能见到大家
Lovely to see you.
如果我用这台特殊的摄像机
So, if I use a camera like this special camera here,
就能亲眼看到马尔科姆呼出的二氧化碳
I can actually see the CO2 being breathed out by Malcolm.
看看这里的屏幕
So, if you have a look here on the monitor,
你会看见二氧化碳被呼了出来
you can see the CO2 being breathed out.
幸运的是 对我们来说是废气的气体
And, luckily, what is a waste gas to us
却是植物进行光合作用的燃料
is fuel for plants in photosynthesis,
植物利用二氧化碳以制♥造♥氧气
where they use this carbon dioxide to create oxygen.
谢谢你 马尔科姆
So, thank you, Malcolm.
但像二氧化碳这种人类呼出的自然产物
But how could something as natural as carbon dioxide,
怎么会对人类有害并造成环境污染的呢
something we breathe out, be bad for us and cause pollution?
当我们燃烧化石燃料中来自古代的碳时
Well, when we burn ancient carbon stored as fossil fuels,
会有二氧化碳排出
we emit carbon dioxide.
化石燃料形成于数百万年前
Now, fossil fuels were formed millions of years ago.
是由泥沙及岩石下的分解层
They were formed when plants and other organisms were laid down
埋藏的植物以及其他生物所形成
in decomposing layers under sediment and rock.
当我们燃烧这些化石燃料时
And when we burn that fossil carbon,
所释放的二氧化碳
it emits much greater amounts
要比马尔科姆呼出的多得多
of carbon dioxide than Malcolm did when he was just breathing.
我们现在要做一个
So, what we're going to do here
非常刺♥激♥的小实验
is a little experiment, very exciting.
我和弗兰打算一起
So, I am going to... We are going to, together, Fran and I,
点燃一些煤粉 一些化石燃料
we're going to set some coal dust, some fossil fuel alight,
我们想看看我们能从中获得多大能量
and we're going to see what kind of energy we can get from that
以及该过程中会产生多少二氧化碳
and how much CO2 can we produce from that.
观众们 我们要倒计时了
So, audience, we're going to need a countdown for this.
跟我一起数 五
With me, five...
四 三 二 一
...four, three, two, one.
看看这个
Look at that.