Where does energy come from? - George Zaidan and Charles Morton

喬治子丹和查爾斯頓：原來世界上所有的能量是……

譯者: Man-Yi Ma 審譯者: Anthea Chen

Energy is not easy to define.

能量很難定義

Things have energy,

物體都有能量

but you can't hold

a bushel of energy in your hands.

但事實上

你無法握住 1 蒲式耳的能量

You can see what it does,

你看得到能量的表現

but you can't see it directly.

但看不到能量

There are different types of energy,

能量有很多種

but the differences between them

但只有 1 點不同

are manifested only in how they make stuff behave.

就是對物體的作用

We do know that the total amount

我們知道

of all the different types of energy in the universe

世上各種能量的總額

is always the same.

永遠不變

And, for chemists, two important types of energy

化學家眼中，有 2 種重要的能量

are chemical potential energy

化學勢能

and kinetic energy.

以及動能

Potential energy is energy waiting to happen.

勢能是蓄勢待發的能量

Think of a stretched rubber band.

像這條被拉長的橡皮筋

If you cut it,

如果把它切斷

all that potential energy

所有的勢能

gets converted to kinetic energy,

會轉換為動能

which is registered by you as pain.

讓你產生痛的感覺

Like a stretched rubber band,

像被拉扯的橡皮筋一樣

chemical bonds also store energy,

化學鍵也會儲存能量

and when those bonds are broken,

當這些鍵被破壞了

that potential energy gets converted

勢能會轉換

to other types of energy,

變成其他能量

like heat or light,

像是光和熱

or gets used to make different bonds.

或形成其他的鍵

Kinetic energy is the energy of motion,

動能是移動中物體具有的能量

and molecules are always moving.

而分子總是動個不停

They're not necessarily going somewhere,

有時毫無章法

though they could be,

有時有明確方向

but they are vibrating,

分子會不斷振動

stretching,

bending,

and/or spinning.

伸展

彎曲

或是旋轉

Take methane,

像是甲烷

which is four hydrogens

它有 4 個氫

attached to a central carbon,

依附著中間的碳

as an example.

我們來看看

Drawn on paper,

如果畫在紙上

it's just a still tetrahedron.

這只是個靜止的 4 面體

But in real life, it's a jiggling mess.

但實際上，它可是不停地在擺動

The kinetic energy of molecules

再來看分子的動能

is exactly the same type of energy

其實很簡單

as the energy you have

和你運動的能量

when you're moving around,

一模一樣

except that you can be still

差異在於你可以靜止不動

and molecules can't.

而分子不能

If you suck the kinetic energy

如果把動能抽離

out of a group of molecules,

很自然地

they'll move less,

分子組會動得更少

but they'll never fully stop.

但絕對不會完全不動

Now, in any group of molecules,

在任何一組分子中

some will have more kinetic energy than others.

有些分子的動能比較多

And if we calculate

經過計算

the average kinetic energy of the group,

整組平均動能的數字

we'd have a number mathematically related to

往往和一個因素有關

temperature.

就是溫度

So, the more kinetic energy

因此，分子群裡

a group of molecules has,

動能越多

the higher its temperature.

溫度就越高

And that means that on a hot day,

也就是說，天氣熱時

the molecules in the air around you

身邊的分子很不安分

are spinning, stretching, bending,

不斷旋轉、伸展、彎曲

and generally shooting around much faster

也會動得比較快

than on a cold day.

比天冷時還快

Now, hot and cold, by the way,

順帶一提，冷與熱

are relative terms.

是相對的

They're always used to compare

都是用來比較

one thing to something else.

比較兩者的差異

So, on that hot summer day,

所以，在炎熱的夏天

the air molecules have more kinetic energy

空氣分子有更多動能

than the molecules in your skin.

比皮膚上的分子還多

So, when those air molecules crash into you,

當空氣分子碰撞皮膚

they transfer some of their energy

會有一部份的能量轉移

to the molecules in your skin,

傳到皮膚上的分子

and you feel that as heat.

你會因此覺得熱

On a cold day,

如果天氣冷

the air molecules have less kinetic energy

空氣分子動能較少

than the molecules in your skin,

比你皮膚上的分子還少

so when you crash into those air molecules,

所以，當你撞到空氣分子

you actually transfer

換你傳遞能量

some of your kinetic energy to them,

將一些動能送出去

and you feel that as cold.

然後你會覺得冷

You can trace the path of energy around you.

你可以觀察身旁的能量傳遞

Try it at your next cookout.

下一次野餐時試試看

You burn charcoal

燒木炭時

and the release of that chemical potential energy

化學勢能會釋放

shows up as extreme heat and light.

產生大量光和熱

The heat then makes the molecules

然後熱會發揮作用

of your burgers, your hot dogs, or your vegetables

改變漢堡、熱狗、或蔬菜分子

vibrate until their own bonds break

振斷食物的鍵

and new chemical structures are formed.

形成新的化學結構

Too much heat and you have a charred mess;

太熱的話，食物會焦掉

just enough and you have dinner.

溫度適中就可以大快朵頤

Once in your body,

食物一但吃進去

the food molecules in your delicious,

不管是美味的

or charred,

或是燒焦的

dinner get broken down,

都會被分解

and the energy released

釋放出能量

is used to either keep you alive right now

維持你的生命

or it's stored for later in different molecules.

或儲存起來，留做他用

As night falls,

天黑後

the hot summer air cools

炎熱的夏季空氣冷卻

and the flow of energy into you slows.

流向你的能量會減慢

Then, as the air reaches your skin temperature,

然後空氣和皮膚的溫度達到一致

for the briefest of moments,

在那瞬間

the flow stops.

流動停止了

And then it starts up again

然後又再開始

in the opposite direction

從反方向流出

as energy leaves the warmer surface of your skin

能量從較溫暖的皮膚表面離去

to return to the universe around you,

回到周遭環境

that energy, neither created nor destroyed,

這種能量不會再生、不會減少

but ever shape-shifting,

但會不斷變形

the chameleon phoenix of our physical world.

像不斷變化的變色龍