(单词翻译:单击)
SciShow is supported by Brilliant.org, a problem-solving website that teaches you how to think like a scientist.
科学秀由Brilliant.org赞助播出。Brilliant.org 一个解决问题，让你像科学家一样思考的网站。
Mmmm, a refreshing glass of cold water. If you think I’m talking about H-2-O, then you’re right.
嗯啊，这是一杯新鲜的凉水。如果你认为我说的是H2O，那么你猜对了。
But I could be sipping on heavy water, or deuterium oxide, aka D-2-O, just as easily.
但是我可能喝的是重水或者说是氧化氘，也称D2O更方便。
Well, not just as easily… it’s super expensive, and you have to, like, buy it from lab supply stores, but you get my point.
好吧，也不是那么容易...超贵的好么，得去实验室用品店才能买到，你懂的。
Deuterium is a form of hydrogen, or isotope,
氘是氢或同位素的一种形式，
with a bonus neutron, which makes it twice as heavy as the regular hydrogen we all know and love.
还有一个额外的中子，这使得重水比我们所知所爱的普通氢重两倍。
That's why when there's deuterium in water molecules, it's about 10% heavier, and we call it 'heavy water.'
这也是为什么当水分子中有氘时会比没有重10%左右，我们将之称为‘重水。’
And one of our patrons on Patreon, who goes by the name, Kutsop,
Patreon上的一位名叫Kutsop的观众
wanted to know what would happen if you just drank a glass of heavy water.
想知道如果喝下一杯重水会怎么样。
Well, in small amounts -- even a glass or two -- heavy water is fine.
少量的——甚至是一杯或两杯——重水是没问题的。
In fact, in combination with an oxygen isotope,
事实上，与一个氧同位素结合，
it's used in lots of nutrition experiments in humans because it's a useful way to track how much energy you're spending.
这经常用于人体营养试验，因为这是一种追踪人体消耗多少能量的有效方法。
But don't go filling up all your bottles with pure deuterium oxide, because too much will almost definitely kill you.
但是将你的所有瓶子都注满纯氧化氘，因为过量的氧化氘几乎绝对致命。
Mice and rats die when about a third of the water in their bodies has deuterium in it.
当老鼠和大鼠体内三分之一的水中含有氘时，就会致命。
Plants also aren't big fans, and will stop growing.
植物们也不喜欢氘，这会使它们停止生长。
The toxicity is related to what's called the kinetic isotope effect.
其毒性和动力学同位素效应有关。
Basically, the extra mass of the isotope slows chemical reactions down --
基本上，同位素的额外量会减缓化学反应——
including all the super important reactions that keep you not dead.
包括所有让你活着的超重要反应。
In the case of heavy water, the bonds between deuterium and oxygen are stronger than the bonds between hydrogen and oxygen in normal water.
重水中，氘和氧之间的纽带比普通水中氢和氧之间的纽带更加强壮。
That means it takes more energy to break those bonds, which slows everything down.
这意味着需要花更多的时间打破这些起减缓作用的纽带。
It's not totally clear how much heavy water would do a person in,
还不完全清楚干掉一个人需要多少种水，
but experts estimate that anything more than 10% of your total water intake could start causing problems.
但专家估计任何超过你的总含水量10%的摄入都可能引起各种问题。
So a sip is okay, but don't push it.
所以一小口是ok的，不要太猛。
Also it's not going to help you at all, and it's going to cost extra money.
这完全无助于你，还费钱。
I don't really know why you would do this.
我也不知道你为什么要这样做。
Still, there is a form of heavy water you should avoid: tritium oxide, or super-heavy water.
反正，还有一些其他重水形式你需要避开：氚氧化物，或超重水。
Instead of hydrogen or deuterium, it contains tritium, an isotope of hydrogen that has two neutrons.
超重水中没有氢或氘，其中却含有超重氢，氢的之中同位素，其中含有两个中子。
And is radioactive. Now, as far as radioactive things go, tritiated water is pretty weak.
而且还是放射性的。就放射性物质而言，氚化水还是相当弱的。
It emits low-energy, which are a type of electron that can't penetrate skin.
它能放射出低能耗，这是一种无法渗透至皮肤的电子。
But drinking them is another story.
但喝下去就是另外一回事了。
There's some evidence that once inside the body,
有很多证据表明，一旦超重水进入体内，
beta particles might even be better at causing cancer than the higher-energy gamma rays that come from things like radium.
β粒子可能甚至比来自放射物中的更高能耗的伽马射线更容易导致癌症。
Scientists don't actually have a great sense of how dangerous tritiated water is,
事实上，科学家们也不清楚氚化水到底有多危险，
they're not just putting it in cups and having people try it, but they assume exposure isn't good.
他们不可能就将氚化水倒入杯中让人尝试，只是这样不好。
We all come into contact with a tiny amount of it naturally, which isn't a big deal.
我们都自然地接触过微量的氚化水，并没什么大不了的。
But because tritiated water is used in nuclear reactors,
但因为氚化水被用于核反应堆中，
the real concern is when those reactors leak, or if there's an accident.
真正该担心的是当这些反应堆泄露时或如果出现事故。
So, I'm not recommending you do this,
所以我不建议这么做，
but if you really want to test out some heavy water, make sure we are talkig about deuterium oxide, not tritiated water.
但是如果你真的想试试重水，一定确保是氧化氘而不是氚化水。
You do not want to be a dead person.
你也不想死的对吧。
Me however, I'll just stick with the stuff that comes out of the water cooler at work,
而我，我还是继续喝公司水冷却器中的水吧，
because it's nice and cool and made up of normal things that I understand.
因为那是由一些我所知道的正常物质组成安全的水。
If you liked learning about the weird chemistry of heavy water, you probably like getting smart and staying smart.
如果你愿意了解关于重水的怪异化学过程，你可能会变得聪明。
Brilliant.org is a problem-solving website that teaches you how to think like a scientist.
Brilliant.org 是一个解决问题，让你像科学家一样思考的网站。
Brilliant presents short, conceptual quizzes that supplement what you have seen on SciShow.
Brilliant提供关于科学秀视频简短的概念性测试补充题。
A great way to retain that information like that is by actively solving problems on Brilliant.
牢记这些科学知识的好方法就是去Brilliant开动脑经解决问题。
Each course guides you through easy and challenging problems with interactive graphics and questions.
每一个课程都用交互式图形学和问题引导你轻松挑战各路难题。
One course, Physics of the Everyday,
Physics of the Everyday，这一课程
teaches you the science of your refrigerator and toilet, atmospheric pressure systems, nuclear reactors, and more.
告诉你关于冰箱和厕所、大气压力系统以及核反应堆的科学知识。
In one lesson, you math your way through estimating what it would take to build a Dyson sphere before our oil reserves run out on Earth.
在其中一课，你要在地球石油储量耗尽前，通过评估出建造一个戴森球体的所需找到出路。
By breaking the problem into bite-sized concepts,
通过将问题分解成小的概念，
thinking clearly through each part, and building up to the stunning conclusion,
通过每个小概念清晰地思考，然后得出惊人结论，
you better understand the process behind Dyson spheres.
你能够更好地理解戴森球体背后的过程。
If humans keep a keen focus on advancing science and math, anything is possible.
如果大家都密切关注科学与数学，任何事都有可能。
4 million people are already using Brilliant, so join them in sharpening your STEM skills.
四百万人已在使用Brilliant，所以加入他们打磨你自己的科学、技术、工程和数学技能。
To support SciShow and learn more about Brilliant, go to brilliant.org/SciShow and sign of for free.
登录brilliant.org/SciShow免费注册，支持科学秀、了解更多关于Brilliant的信息。
