Why do you get shocked sometimes when you get out of your car?

為什麼有時候下車的時候會被嚇到？

Or when you touch a doorknob?

還是當你觸摸門把手的時候？

Or when you take off a sweater and hug someone?

或者當你脫下毛衣擁抱別人的時候？

And is there a way to not get shocked?

那有沒有辦法不被嚇到呢？

To prevent this from happening, you have to figure out what's happening.

為了防止這種情況的發生，你必須弄清楚發生了什麼。

So, this is called a Van de Graaff generator.

所以，這就是所謂的范德格拉夫發生器。

I use it a lot in science demos for kids.

我在給孩子們做科學演示時經常使用它。

It's a machine that builds up a ton of static charge - that is, a bunch of positive charges on the outside of this metal sphere, so that when I bring this smaller grounded metal sphere close to it, it discharges through the air in a giant metal spark that will shock you.

這臺機器可以建立起一噸的靜電荷--也就是在這個金屬球體的外面有一堆正電荷，所以當我把這個較小的接地金屬球體靠近它時，它就會在空氣中放電，產生巨大的金屬火花，讓你震驚。

Ugh, I hate that.

呃，我討厭這樣。

The kids love it.

孩子們喜歡它。

So, this is where it gets fun.

所以，這就是它變得有趣的地方。

If I put a metal pan on top of the Van de Graaff generator, it should take on the same positive charge as the sphere because it's conductive.

如果我在范德格拉夫發生器上放一個金屬盤，它應該和球體一樣帶正電，因為它是導電的。

But like charges repel.

但就像指控一樣的排斥。

So, when I turn this on, the pan should... fly off.

所以，當我打開這個，鍋應該... ...飛走。

And it does.

而且確實如此。

Now, one kid saw this and asked what would happen if we put the Styrofoam ball she was holding on top of the generator.

現在，有一個孩子看到了，就問如果我們把她手裡的泡沫塑料球放在發電機上面會怎麼樣。

Let's try it.

讓我們試試吧。

But I told her probably nothing would happen, because Styrofoam is an insulator.

但我告訴她可能不會發生什麼，因為泡沫塑料是絕緣體。

So, I assumed there's no way you can pass charge to it.

所以，我以為你不可能把電荷傳給它。

Let's see.

讓我看看

I stood there confused.

我困惑地站在那裡。

Insulators don't conduct electricity, right?

絕緣體不會導電吧？

So, how can you charge them?

那麼，如何向他們收費呢？

Well, in fact, it's very easy.

嗯，事實上，這很容易。

This balloon... is now charged.

這個氣球... 現在是充電的。

See?

看到了嗎？

And this tape is now charged.

而這盤帶子現在是收費的。

See?

看到了嗎？

And these are both insulators - just not perfect insulators.

而這些都是絕緣體--只是不是完美的絕緣體。

In very violent events, electrons from the atoms in one material can get stripped off and passed to another material, causing both materials to become charged, this one positively, because it lost electrons, and this one negatively, because it gained electrons.

在非常劇烈的事件中，一種材料中原子的電子會被剝離出來，傳遞到另一種材料中，導致兩種材料都帶電，這種材料帶正電，因為它失去了電子，而這種材料帶負電，因為它獲得了電子。

Even if they're usually insulators, and for the poor tiny atoms in these materials, rubbing them together would definitely be considered an unsettling violent event.

就算它們平時是絕緣體，對於這些材料中可憐的微小原子來說，將它們摩擦在一起，也絕對會被認為是一件令人不安的暴力事件。

Now, back to the car.

現在，回到車上。

The violent event here is when you get out of the car, you slide across the seat, and both you and the seat become charged.

這裡的暴力事件是當你下車時，你從座位上滑過，你和座位都變成了帶電的。

And now some of that charge will leave your body into the air.

而現在，一些電荷會離開你的身體，進入空氣中。

But if the air is cold enough and dry enough, and you touch the metal soon enough, that charge will quickly leave your body into the metal, and you will feel that.

但如果空氣足夠冷，足夠乾燥，你很快就會接觸到金屬，那電荷就會很快離開你的身體進入金屬，你會感覺到。

And you'll hear it, too, as a shock.

你聽了也會嚇一跳。

So, how do you prevent this from happening?

那麼，如何防止這種情況的發生呢？

Well, don't keep yourself isolated.

好吧，不要把自己孤立起來。

As you get out of the car, touch the metal on the side of the car.

下車的時候，摸一下車側的金屬。

And even if charge is building up on you, it'll continually flow into the metal, and it won't build up enough on you to shock you.

而且即使你身上積聚了電荷，它也會不斷地流入金屬中，不會積聚在你身上，不會讓你受到衝擊。

Problem solved.

問題解決了。

Either that, or rub yourself all over with dryer sheets.

要不，就用烘乾機的床單把自己擦遍。

I don't know if that works.

我不知道這是否有效。

Someone please try it and let me know.

誰來試試，讓我知道。

So, now for this insulator, there was no violent event.

所以，現在對於這個絕緣體來說，並沒有發生暴力事件。

Or was there?

還是有的？

See, air is usually an insulator, too, which is why you're not shocked by your outlet until you stick metal in it.

你看，空氣通常也是一種絕緣體，這就是為什麼你的插座不插金屬就不會被電擊的原因。

Air is an insulator until the voltage, which is related to the amount of surface charge on here, gets so high that electricity can travel through the air.

空氣是一個絕緣體，直到電壓，這與這裡的表面電荷量有關，變得如此之高，以至於電可以在空氣中傳播。

Electrons are stripped off of the air molecules along the way in a process called ionization, which releases light, and you see a spark.

電子被從空氣分子中剝離出來，在這個過程中被稱為電離，釋放出光，你就會看到火花。

But you have to get the voltage really high for this to happen, so high that overcomes the insulating properties of air.

但你必須讓電壓非常高才行，高到能克服空氣的絕緣性能。

So high that it overcomes the insulating properties of Styrofoam, and the Styrofoam takes on a surface charge that repels the metal sphere.

如此之高，以至於克服了泡沫塑料的絕緣性能，泡沫塑料就會產生表面電荷，排斥金屬球。

Large enough for the insulating plastic on this pom-pom to repel itself, so that they stick up - at least on the top.

足夠大，這個絨球上的絕緣塑膠可以自我排斥，所以它們會粘起來--至少在頂部。

On the bottom, there is more going on where the pom-pom sticks to the sphere, and it has to do with electrical induction.

在底部，絨球粘在球體上的地方還有更多的事情，它與電感應有關。

But we'll leave that for another video.

但我們會把這個留給另一個視頻。

Thank you so much for watching.

謝謝你的觀看。

I'm going to see if I can get my hair to stand up, if there's not too much moisture.

如果沒有太多水分的話，我打算看看能不能讓我的頭髮立起來。

Although it rained today, and it's pretty warm.

雖然今天下了雨，而且很暖和。

Nothing's happening.

什麼都沒有發生。

It's too humid, and this thing's not big enough.

太潮溼了，這個東西不夠大。

It's going to shock me.

這會讓我震驚的。

Ah!

啊！

It didn't!

它沒有！