Now, I know what you're thinking: "I know what a mole is,

我知道你在想什麼：「我知道什麼是鼴鼠，

it's a small furry creature that digs holes in the ground and destroys gardens."

牠是一種在地下挖洞，摧毀花園的小毛絨絨生物。」

And some of you might be thinking that it's a growth on your aunt's face with hairs sticking out of it.

有些人也許會認為是在阿姨臉上，並帶有幾根細毛的痣。

Well, in this case, a mole is a concept that we use in chemistry to count molecules,

但今天所講的莫耳， 是化學中的一個概念，用來計算分子、

atoms, just about anything extremely small.

原子、或是任何極小物質的數量。

Have you ever wondered how many atoms there are in the universe?

你曾經想過這個宇宙到底有多少的原子嗎？

Or in your body? Or even in a grain of sand?

或是你的身體裡？或是在一粒沙子裡？

Scientists have wanted to answer that question,

科學家想解開這個問題，

but how do you count something as small as an atom?

但是你要如何計算小到像原子的東西？

Well, in 1811, someone had an idea that if you had equal volumes

在 1811 年，有個人突發奇想，認為 如果你有相同體積

of gases, at the same temperature and pressure,

的氣體，在相同的溫度及壓力下，

they would contain an equal number of particles.

它們應該會有相同的分子數量。

His name was Lorenzo Romano Amedeo Carlo Avogadro.

他的名字是 Lorenzo Romano Amedeo Carlo Avogadro （亞佛加厥）。

I wonder how long it took him to sign autographs.

我懷疑他要花多久時間簽名。

Unfortunately for Avogadro, most scientists didn't accept the idea of the atom,

不幸的是，大部份的科學家不接受這個想法，

and there was no way to prove he was right.

而他也沒有方法可以證明他是對的。

There was no clear difference between atoms and molecules.

原子和分子之間並沒有明顯的差異。

Most scientists looked at Avogadro's work as purely hypothetical,

大多數的科學家認為 亞佛加厥的理論純綷是個假說，

and didn't give it much thought.

並沒有特別去思考這件事。

But it turned out he was right! By late 1860,

但事實證明他是對的 ! 1860 年底，

Avogadro was proven correct, and his work helped lay the foundation

亞佛加厥的想法被證明是對的，而且他的努力奠定了

for the atomic theory. Unfortunately, Avogadro died in 1856.

原子理論的基石。不幸的是，亞佛加厥死於 1856 年。

Now the thing is that the amount of particles in even small samples

問題是，即使是小東西上的分子總數也是

is tremendous. For example,

非常巨大的。舉例來說，

If you have a balloon of any gas at zero degrees Celcius,

假使你有一個汽球，裝進任一種氣體， 在攝氏 0 度

and at a pressure of one atmosphere, then you have precisely

和一大氣壓的條件下，那你會有剛剛好

six hundred and two sextillion gas particles.

602 乘 10 的 21 次方個氣體分子。

That is, you have six with 23 zeros after it particles of gas in the container.

就是 6 後面帶有 23 個 0， 這麼多個分子在裡面。

Or in scientific notation, 6.02 times 10 to the 23rd particles.

或用科學記號表示為 6.02 × 10 23 個分子。

This example is a little misleading,

這個例子有點誤導人，

because gases take up a lot of space due to the high kinetic energy

因為高動能的氣體分子會佔用較大的空間，

of the gas particles, and it leaves you thinking atoms are bigger than they really are.

這讓你感覺原子比實際大小的還要大。

Instead, think of water molecules.

相對地，我們看一下水分子。

If you pour 18.01 grams of water into a glass,

如果你倒入 18.01 公克的水到杯子裡，

which is 18.01 milliliters, which is like three and a half teaspoons of water,

就是 18.01 毫升，大約是三個半茶匙的水，

you'll have 602 sextillion molecules of water.

你就有 6.02 × 10 23 個水分子。

Since Lorenzo Romano - uh, never mind - Avogadro was the first one to come up with this idea,

自從 Lorenzo Romano……嗯，算了。 亞佛加厥是第一位提出這個想法的人，

scientists named the number 6.02 times 10 to the 23rd after him.

科學家用他的名字來命名 6.02 × 10 23 這個數字。

It is simply known as Avogadros's number.

這就是熟知的亞佛加厥常數。

Now, back to the mole. Not that mole.

現在，回到莫耳。不是在說鼴鼠。

This mole. Yep, this number has a second name.

這個莫耳。沒錯，這個常數有另一個名字。

The mole. Chemists use the term mole

莫耳，化學家使用莫耳這個術語

to refer to the quantities that are at the magnitude of 602 sextillion.

來表示 6.02 × 10 23 這個數量。

This is known as a molar quantity.

就是大家知道的莫耳常數。

Atoms and molecules are so small, that chemists have bundled them into groups called moles.

原子和分子太小了，所以化學家將它們分成一群一群， 每一群就叫做一莫耳。

Moles are hard for students to understand because they have a hard time

莫耳對於學生是很難了解的，因為他們很難想像

picturing the size of a mole,

1 莫耳的數量，

or of 602 sextillion.

或是 6.02 × 10 23。

It's just too big to wrap our brains around.

它實在大到大腦難以理解

Remember our 18.01 milliliters of water?

記得剛剛說的 18.01 毫升的水嗎？

Well, that's a mole of water.

那就是 1 莫耳的水。

But how much is that?

但是這有多少？

Exactly what does 602 sextillion look like?

6.02 × 10 23 看起來像什麼？

Maybe this'll help.

也許這有幫助。

Exchange the water particles for donuts.

用甜甜圈來代替水分子。

If you had a mole of donuts, they would cover the entire earth

假如你有 1 莫耳的甜甜圈，它們可以覆蓋整個地球表面

to a depth of eight kilometers,

到 8 公里高，

which is about five miles.

大約是 5 英哩。

You really need a lot of coffee for that.

你需要很多咖啡來配。

If you had a mole of basketballs, you could create a new planet

如果你有 1 莫耳的籃球，你可以製造和地球

the size of the earth.

一樣大的星球。

If you received a mole of pennies on the day you were born and spent a million dollars

如果你一出生時，你有 1 莫耳的錢，你每一秒花一百萬

a second until the day you died at the age of 100, you would still have more than 99.99%

直到 100 歲你死的那一天，你還有 99.99% 以上

of your money in the bank.

的錢在銀行裡。

OK. Now we sort of have an idea how large the mole is.

好了。現在我們大概對 1 莫耳有個概念了。

So how do we use it?

我們如何用它？

You might be surprised to know that chemists use it the same way

你也許會驚訝化學家使用它的方法， 就如同

you use pounds to buy grapes, deli meat, or eggs.

你用「磅」來買葡萄，熟食肉類，或雞蛋。

When you go to the grocery store, you don't go to the deli counter

當你到雜貨店時，你不會走到櫃台

and ask for 43 slices of salami, you buy your salami by the pound.

要 43 片臘腸，你會買幾磅的臘腸。

When you buy your eggs, you buy a dozen eggs.

當你買雞蛋時，你會買一打雞蛋。

When we hear the word dozen, we probably think of the number 12.

當我們聽到「打」這個字，我們會想到數字 12。

We also know that a pair is two,

我們也知道一雙就是 2，

a baker's dozen is 13,

麵包師父的一打是 13，

a gross is 144, and a ream of paper is - anybody?

一籮是 144，一令紙……誰知道？

A ream is 500.

一令紙是 500 張。

Well, a mole is really the same thing.

一莫耳也是一樣的。

For a chemist, a mole conjures up the number 6.02 times 10 to the 23rd,

對化學家而言，1 莫耳就是 6.02 × 10 23，

not a fuzzy little animal. The only difference is

而不是毛絨絨的動物。唯一的差別是

that the other quantities are more familiar to us.

我們比較熟悉其他的計數單位。

So there you have it - the story of the mole,

現在你知道了──莫耳的故事、

Avogadro, basketballs, and how to buy salami at the grocery store.

亞佛加厥、籃球、還有去雜貨店怎麼買臘腸。