Acids and bases are everywhere.
酸与碱处处存在。
They're used to make foods, soaps and detergents, fertilizers, explosives, dyes, plastics, pesticides, even paper.
它们被用来制造食物、香皂、清洁剂、化肥、炸药、染料、塑料、农药甚至纸张。
Our stomachs are very acidic. Our blood is slightly basic.
我们的胃里是强酸性的。我们的血液是弱碱性的。
Our proteins are made up of amino acids, and the letters in our genetic code, those As, Ts, Cs, and Gs, are all bases.
蛋白质是由氨基酸组成的，那些在我们基因密码中的字母，诸如A，T，C和G，都是碱性的。
You were probably taught how acids and bases behave on the molecular level.
可能你已经学过酸分子和碱分子是如何反应的了。
You were probably never taught that a long time ago, like ancient Greek ago,
但是，你可能从不知道，在比古希腊时代还久远的时候，
before anyone knew about atoms or molecules, acids and bases were defined by how they behaved.
在还没有人知道原子或者分子之前，酸和碱的定义已经因他们的反应特点确定了。
Acids tasted sour and corroded metal.
酸的味道很酸，腐蚀金属。
Bases felt slippery and could somehow counteract acids.
碱触感滑，并且能神奇的中和酸。
When molecules dissolved in water interact, they are exchanging two main currencies with their surroundings:
当分子溶于水中相互作用时，他们会交换两种主要流通物质和其周围的物质：
protons, also known as hydrogen ions, and electrons.
质子，也叫做氢离子，和电子。
Depending on how a molecule is composed or shaped,
在与其它的成员交换过程中，
it may be willing to donate or accept either protons or electrons with some other community member.
分子是给出质子或电子还是接受，取决于它们的分子结构是如何组成和形成的。
And some molecules are far more aggressive than others when it comes to donating or accepting either currency.
有一些分子不论是给出或是接受时都比其他的分子强势许多。
Remember that protons are positively charged and electrons are negatively charged.
记住，质子带正电荷，电子是带负电荷的。
So, if a molecule is willing to give up a proton, that's not too different from it being willing to accept an electron
所以，要是一个分子愿意放弃一个质子，就和这个分子愿意接收一个电子是一样的效果，
either way it's becoming more negatively charged.
不论哪个方式，都使分子带更多负电。
Other molecules are willing to accept a proton or give up an electron.
其它的分子要接收一个质子或放弃一个电子。
These are becoming more positively charged.
那它们就会变成正电。
Some substances are so aggressive about donating their protons that when they get a chance,
一些物质十分强势地给出质子，一旦得到机会，
all of the molecules in a sample will dump a proton, sometimes more than one, to the surrounding water molecules.
采样中所有的分子都会向周围的水分子中扔掉一个质子，有时候扔掉的还不止一个。
We call these strong acids.
我们称这种分子为强酸。

Meanwhile, some compounds are so ready to accept a proton that they won't wait around,
同时，一些混合物迫不及待的需要接收一个质子，它们不会温和等待，
they'll just rip one off water, which usually has two protons but is generous enough to hang out with just one.
反而会从有两个质子的水中掠夺一个，不过，水很大方，只有一个质子也可以。
We call these strong bases.
我们叫这种分子为强碱。
Other acids and bases are not so strong.
其余的酸和碱没有那么强。
They may donate just a few of their protons to water or accept just a few protons from water,
它们只往水中给出或接受几个质子，
but most of their molecules stay exactly the same.
但是大多数分子都保持不变。
If left alone in water, they'll reach some equilibrium point
如果他们被单独置于水中，它们就会达到一个交换平衡点，
where maybe only one out of a hundred or one out of ten thousand of their molecules has exchanged currency with water.
可能是当百分之一或万分之一的分子在水中交换了流通物的时候。
As you might guess, we label these acids and bases weak, but in the common sense of the word, they're not weak.
而你可能会认为我们把这种酸和碱定为弱酸和弱碱，但是常识是它们并不弱。
The vinegar in your salad dressing that you can smell from across the room, that is a weak acid.
沙拉中的调味醋，味道大得在房间的另一边都能闻到，它是弱酸。
The ammonia you spray on glass for a streak-free shine, that is a weak base.
你为了让玻璃干净明亮喷上去的氨水是弱碱。
So, it doesn't take much to be an active player in the chemical economy.
所以，在化学界的经济里，活跃分子并不难当。
Most acid-base chemistry takes place in water,
大多数的酸碱化学反应都在水中发生，
which can act as either an acid or a base, accepting deposits and enabling withdrawals like a 24-hour molecular ATM.
像24小时的分子柜员机一样，酸提供存款，碱提取存款。
And when a proton-deposit customer, that's an acid, and a proton-withdrawal customer, the base,
当质子提供客户--酸，质子提取客户--碱，
shop at the same time, their net effect on water's account may cancel out, and we call this neutralization.
同时消费，它们在水的账户收支相互抵消了，我们称之为中和作用。
Now, certain molecules can behave as acids or bases without water, but that's another story.
现在，一些分子在没有水的情况下也可以发生酸碱反应，这另当别论。
Let's end by saluting water as the resilient and fair banker for acids and bases.
最后，我们向水致敬，因为它平衡酸和碱，是一位公平的银行家。
It's always open for business, doesn't charge interest,
因为它总是开放服务，不收利息，
and will never foreclose on your molecules, which is more than I can say for. Waah-waah.
并且永远不会阻止你赎回你的分子，这点真是太好了。哇哇。