is quite a precarious task.

是很困難的 會搖搖欲墜

It is easy to see why tough heavy object are unstable.

堅硬重物不易立起的原因很簡單

They just…wanna fall down.

它們就是會自然而然的倒下

Any little nudge, will put it off balance,

只要輕輕一推 就會失去平衡

with gravity, happy to pull its center of mass even more off balance

因為地心引力的關係 一失去重心就會倒下

And the more off balance, it is the more gravity pulls in too!

重心越傾斜 地心引力的作用就越強烈

Physicist calls this kind of tipping an...Inverted Pendulum.

物理學家稱這種現象為 倒單擺作用

Because its kind of, like…an upside-down pendulum.

因為這有點像上下顛倒的鐘擺

And careful mathematical analysis of Inverted Pendulums...will tell you the obvious,

經過精密的數學分析 結果顯而易見

they’re really… unstable.

這真的…很不穩定

In fact, this equation predicts that

事實上 藉由公式運算 能夠預測

if a perfectly balanced pencil with a perfectly-sharped tip,

一隻有著完美筆尖的鉛筆 完美平衡後

will do get nudge, off balance, by just one ten thousandth of the width of an atom.

只要輕輕一推 哪怕只偏離0.0001個原子量

It would take only three seconds, to fall over...

只要三秒鐘 鉛筆就會完全倒下

There are indeed acrobats, who can balance poles, with other acrobats on top.

有些雜技演員 能平衡上頭站了一人的長竿

And the robots, they can balance and, catch and throw, upright sticks!

有種機器人能 平衡 甚至拋接 直立的竹籤

And the people who make... seemingly impossible, artistic, rock stacks.

有人還能以不可思議的方式堆疊石頭

But in all these cases,

但 在以上這些情況

keeping the objects balance, either requires an active stabilization effort,

要維持平衡 除了利用動態平衡以外

Or else, carefully taking advantage of the fact that

另一個方法是利用物理現象-

the balancing point...isn't actually...a point!

所謂的平衡點 其實並不是一個點!

So, the question is this:

問題來了

Can you balance a pencil sharpened to a perfect, single, atom-wide tip, on its tip?

要怎麼用原子大小的尖端 立起一隻鉛筆?

Without active stabilization?

而且不利用動態平衡?

Well, to start, you better get rid of the air bumping in besides the pencil.

首先 要排除鉛筆四周流動的空氣粒子

Since the kinetic energy of a typical oxygen molecule,

因為一個氧分子的動能

is enough to destabilize the pencil.

就足夠使鉛筆失去平衡

Remember, if the pencil gets off center by even ten thousandth of the width of an atom,

記住 就算鉛筆重心只偏移0.0001個原子量

it would fall down in, under three seconds.

它就會在三秒後倒下

And you better cool the pencil and table down as close to absolute zero, as you can...

另外 要盡量把鉛筆和桌子都冷卻到絕對零度

since the thermal jiggling of their atoms when they're hotter, are similarly jiggle the pencil off balance.

因為熱能會使原子運動 溫度越高越難平衡

But even then, matter add very small scales has spread out wape like nature

但即使如此 還是會有自然的微小波動

which means that you cannot have both pencil perfectly upright,

也就是說 保持鉛筆完美平衡的同時

and not moving at the same time.

無法維持鉛筆的絕對靜止

And while this "quantum effect" is never a real life inhibitor of the precarious pencil balancing?

這種量子效應從不存在於鉛筆直立中

It means, you never even could succeed...

所以 永遠無法成功立起鉛筆

However, it is still fun to see, how long you can keep a pencil balanced on your fingertip.

但是 挑戰在指尖立起鉛筆 還是很好玩

The shorter the pencil, the harder it is.

鉛筆越短就越困難

My best time for a standard nineteen centimeter pencil

我平衡標準19公分鉛筆的最長時間是

was one point three seconds.

1.3秒

Do you think you can beat that?

你有辦法超過我嗎?

This minute physics video is brought to you by audible.com

這部影片由audible.com贊助播出

one of the leading providers online, audio books, and all types of media,

audible是線上有聲書與媒體的領導品牌

either fiction, non-fiction, and periodicals..

產品包含小說 非小說 與期刊

I'd like to recommend "The Tipping Point" by Malcolm Gladwell this week.

本周推薦Gladwell的The Tipping Point

It is a book about exponential increases and spreads of trends,

這本書是關於流行趨勢的指數增加與傳播

social trends, academic, that sort of thing,

像是社會風潮 學術 等等

and...the mathematics of, the mathematics of... balancing an object, on its...tip,

還有平衡物品的…數學…數學運算

so...anyway,"The Tipping Point", by Malcolm Gladwell,

總之 推薦Gladwell的The Tipping Point

audible.com, supports minute physics.

還有我們的贊助商 audible.com

Without them, we won't be able to do... what we do!

少了他們 我們節目無法成功播出

So, thank you to audible and

謝謝收看

have an audible.com/minutephysics to get your free audio book.

下載免費有聲書請上audible.com/minutephysics