They're used to make foods,

它們被用來製作食物，

soaps and detergents,

香皂和清潔劑，

fertilizers,

化肥，

explosives,

炸藥，

dyes,

染料，

plastics,

塑膠，

pesticides,

農藥，

even paper.

還有紙。

Our stomachs are very acidic.

我們的胃裡是強酸性的。

Our blood is slightly basic.

我們的血液是呈弱鹼的。

Our proteins are made up of amino acids,

我們的蛋白質是由氨基酸組成的，

and the letters in our genetic code,

還有那些遺傳密碼中的字母，

those As, Ts, Cs, and Gs,

As,Ts, Cs, 和 Gs，

are all bases.

都是堿。

You were probably taught

你可能學過

how acids and bases behave

分子級的酸和堿

on the molecular level.

如何作用。

You were probably never taught

你可能從不知道

that a long time ago,

很久以前，

like ancient Greek ago,

比古希臘還往前，

before anyone knew about atoms or molecules,

在沒有人知道原子或分子時，

acids and bases were defined

酸和堿已經因它們的

by how they behaved.

作用表現而有定義。

Acids tasted sour and corroded metal.

酸嘗起來是酸的，還腐蝕金屬。

Bases felt slippery

堿觸感滑

and could somehow counteract acids.

還能一定程度上抵消酸的作用。

When molecules dissolved in water interact,

當在水中溶解的分子相互作用，

they are exchanging two main currencies

它們與周圍的物質交換

with their surroundings:

兩個主要流通物

protons, also known as hydrogen ions,

質子，也就是氫離子，

and electrons.

以及電子。

Depending on how a molecule is composed or shaped,

取決於分子的組成和形狀，

it may be willing to donate or accept

在這個群體中，它與其他的成員之間

either protons or electrons

可能願意釋放，或者接受

with some other community member.

質子或電子。

And some molecules are far more aggressive than others

有些分子在釋放或接受任一流通物時

when it comes to donating or accepting either currency.

比其他分子強悍許多。

Remember that protons are positively charged

切記質子是帶正電荷的

and electrons are negatively charged.

電子是帶負電荷的。

So, if a molecule is willing to give up a proton,

所以，如果一個分子要釋放一個質子，

that's not too different

和接收一個電子

from it being willing to accept an electron --

不會有什麼大的差異

either way it's becoming more negatively charged.

任何一種方式都只會讓它帶更多負電荷。

Other molecules are willing to accept a proton

其它分子想要接收質子

or give up an electron.

或釋放一個電子。

These are becoming more positively charged.

這些就變得帶有更多正電荷。

Some substances are so aggressive

一些物質在釋放它們的質子時

about donating their protons

表現得十分強勢，

that when they get a chance,

一旦得到機會，

all of the molecules in a sample

樣本中所有的分子都會

will dump a proton,

釋放出一個質子，

sometimes more than one,

有時是多個

to the surrounding water molecules.

至周圍的水分子中。

We call these strong acids.

我們稱這些為強酸。

Meanwhile, some compounds are so ready

同時，一些化合物迫不及待

to accept a proton

需要一個質子，

that they won't wait around,

它們不會傻等，

they'll just rip one off water,

而是直接從有兩個質子的水分子

which usually has two protons

中搶一個過來，

but is generous enough to hang out with just one.

但水分子很大方，剩一個質子也行。

We call these strong bases.

我們把這些叫做強鹼。

Other acids and bases are not so strong.

其它的酸和堿沒有那麼強。

They may donate just a few of their protons to water

它們可以往水中釋放少量質子

or accept just a few protons from water,

或從水中接受少量質子，

but most of their molecules stay exactly the same.

但是它們的大多數分子都保持不變。

If left alone in water,

如果被單獨置於水中，

they'll reach some equilibrium point

在百分之一或

where maybe only one out of a hundred

萬分之一的分子

or one out of ten thousand of their molecules

與水交互流通時

has exchanged currency with water.

達到某個平衡點

As you might guess,

你可能猜測，

we label these acids and bases weak,

我們把這些酸和堿標記為做弱酸，弱鹼，

but in the common sense of the word,

但是常識中，

they're not weak.

它們不弱。

The vinegar in your salad dressing

你的沙拉調味的醋

that you can smell from across the room,

的味道你能在整個房間裡聞到，

that is a weak acid.

它是弱酸。

The ammonia you spray on glass

氨水噴在玻璃上

for a streak-free shine,

讓玻璃晶瑩剔透，

that is a weak base.

那是弱鹼。

So, it doesn't take much to be an active player

所以，在化學的經濟體系裡，

in the chemical economy.

不必投入太多也能成為活躍玩家。

Most acid-base chemistry takes place in water,

大多數的酸鹼化學過程都發生在水中，

which can act as either an acid or a base,

水像一個24小時分子ATM，

accepting deposits and enabling withdrawals

通過”吸納存款“和”授權取款“

like a 24-hour molecular ATM.

起到酸或堿的作用。

And when a proton-deposit customer,

但一個客戶存入質子，

that's an acid,

它就是酸，

and a proton-withdrawal customer,

當一個客戶提取質子，

the base,

它是堿，

shop at the same time,

當他們同時購物

their net effect on water's account

他們在水中的有效效應

may cancel out,

會抵消，

and we call this neutralization.

我們把這個叫做中和作用。

Now, certain molecules can behave

現在，一些分子不必融水

as acids or bases without water,

就可以起到酸和堿的作用，

but that's another story.

但那就是另一回事了。

Let's end by saluting water

最後，我們向水致敬

as the resilient and fair banker

因為它平衡酸和堿

for acids and bases.

公平的銀行家。

It's always open for business,

它總對商家開放，

doesn't charge interest,

也不收利息，

and will never foreclose on your molecules,

並且永遠不會阻止你贖回你的分子，

which is more than I can say for [bleep].

酷斃了。

Waah-waah.

哇-哇