Ancient people used this glue, made from a mixture of animal bone and plant materials, to waterproof baskets and construct utensils.

古代人類使用這個從動物骨頭與植物材料混合而成的膠水來製作防水的籃子，還有建造器皿。

And for thousands of years after, plants and animals were the glue that held human civilization together.

過了數千年之後，植物與動物成為將人類文明黏合在一起的黏著劑。

Today, we have enough types of tape and glue to build and repair almost anything.

今天，我們有許多類型的膠帶與膠水，幾乎可以用來建造以及修復所有東西。

But what gives glue and tape their stickiness?

但膠水與膠帶的黏性從何而來？

And is one stronger than the other?

而是不是有一方黏性比較強呢？

Adhesives can be made from synthetic molecules or natural proteins and carbohydrates like the vegetable starch dextrin,

黏著劑可以用人造分子或是天然的蛋白質跟碳水化合物製作，像蔬菜的澱粉、葡聚糖、

the milk protein casein, and the terpenes in tree resin.

牛奶的蛋白質、酪蛋白還有樹脂裡的萜烯。

In order to work, glue and tape need both adhesive bonds and cohesive bonds.

為了讓它發生作用，膠水與膠帶都需要附著鍵與聚合鍵。

Adhesive bonds occur between an adhesive's molecules and the molecules of whatever it's sticking to.

附著鍵存在黏著物品的分子，還有被黏著物品的分子間。

Cohesive bonds happen between a glue or tape's own molecules, holding it together.

聚合鍵則是發生在膠水或膠帶自己的分子之間，將它們抓住不分開。

Most glues consist of adhesive polymers dissolved in a solvent that prevents them from sticking to the inside of the bottle.

大部分膠水是由溶解在溶劑中的黏著聚合物組成，這種溶劑能避免膠水黏在瓶子裡。

The strong smell of many glues comes from the solvent, which evaporates when exposed to air.

許多膠水的氣味就是來自這種溶劑，它暴露在空氣中就會蒸發，產生氣味。

Some glues use water as a solvent, but others use chemicals that can be harmful to inhale.

有些膠水用水當溶劑，但其他的則是使用化學藥劑，吸入人體會造成傷害。

Glues with two or more components that chemically react instead of just drying can create stronger bonds.

有些膠水使用兩種或更多的成分來產生化學反應，而非乾燥的方式可以創造出更強的鍵能。

Both the adhesive and cohesive bonds of glue are strong, but the drying process makes them irreversible.

膠水的附著鍵跟聚合鍵的鍵能都很強，但乾燥的過程使它們變成不可逆。

This is why, if a glued surface is broken after it dries, it can't be reattached without new glue.

這就是為什麼如果一個膠水黏著的表面在乾燥之後破裂，若不用新的膠水就不能重新黏回去。

By contrast, when tape is applied to a surface, it forms weaker, reversible bonds, so you can peel a piece of tape off a surface and use it again.

相反地，當你用膠帶黏在表面它會形成較弱、可逆的鍵結，所以你從物品表面撕下一條膠帶後，還是能再次使用它。

These weak bonds, called Van der Waals forces, can occur between any two materials, but only if they're extremely close together, closer than the naked eye can see.

這樣的弱鍵結稱為凡得瓦力，任何兩個物體之間都可以發生，但只有當他們非常接近，比肉眼可見的還要近時才會發生。

Tape usually consists of a backing coated with a combination of a rubber or rubber-like "stretchy" component, and a compound called a tackifier.

膠帶通常有襯背，襯背由像膠或類似像膠的彈性元素組成，再加上一種增黏劑的混合物。

That's the "sticky" component.

那就是讓膠帶「黏著」的成分。

A tape's stickiness is determined by the proportion of elastic component and tackifier,

膠帶的黏著度取決於彈性成份和增黏劑的比例、

the thickness of adhesive spread onto the backing, and the type of backing material.

襯背上塗抹的增黏劑厚度，還有襯背的材質。

No chemical reaction occurs when tape is pressed onto a surface.

當膠帶被黏到物品表面上時，不會有化學反應發生。

Instead, the soft adhesive flows into the cracks and grooves of the surface.

而是軟黏著劑流進表面的縫隙與凹槽中。

This ability to slide into cracks and then stay in place is called viscoelasticity.

這種滑入縫隙並留存在那裡的能力，稱作黏彈性。

Once the viscoelastic adhesive fills these microscopic crevices, it is close enough to form Van der Waals forces.

一旦黏彈的黏著劑填滿這些微小的縫隙，它就近到足以產生凡得瓦力。

So what's the world's strongest adhesive?

所以哪一個是世界上最強的黏著劑？

Well, there's no one answer.

看來我們還沒有唯一的答案。

In terms of absolute strength of adhesive bonds, glue is stronger than tape, but no single adhesive works well in all circumstances.

從聚合鍵的絕對強度來看，膠水比膠帶還強，但沒有單一種黏著劑能在所有情況下都很有用。

Of the glues, cyanoacrylates, or super glues, may form the strongest bonds,

眾多膠水中，氰丙烯酸酯，或稱超能膠 (三秒膠、快乾膠)可能可以形成最強的鍵能。

but two-component epoxy glues have much higher resistance to heat and shearing, and are compatible with a wider range of surfaces.

但兩種成份的環氧樹脂膠對溫度和剪力的耐受度較高，且適合用在更廣泛的表面上。

So, if you wanted to dangle an anvil in the air, super glue might be your best bet.

所以，如果你想要鐵砧懸掛在空中，超能膠可能是你最好的選擇。

But if you're doing so over an active volcano, you'd want an epoxy instead.

但，如果你想要在活火山上做這件事，你反而會想用環氧樹脂膠。

And in order to work at all, glues need enough real estate where surfaces touch.

為了讓膠水有效作用，需要有足夠的表面接觸面積。

If for some reason you wanted to make a chain of bowling balls, duct tape would be better.

如果因為某個原因，你想要製作一個保齡球，鍊布膠帶 (牛皮膠帶) 會比較適合。

Engineers weigh similar, if less absurd, factors all the time.

工程師也總是在衡量類似的因素，但沒那麼荒謬就是了。

Choosing the right glue to withstand the heat inside an engine is a matter of life and death.

選用正確的膠水好用來承受引擎中的高溫是個攸關生死的大事。

And though the strength of duct tape's adhesive bonds can't compete with those of epoxy glues,

雖然布膠帶的聚合鍵沒有辦法跟環氧樹脂膠水比，

tape does have the advantage of instantaneous stickiness in an emergency.

膠帶在處理緊急事件的立即性上還是有優勢的。

Glue may be necessary to get a rocket to space, but when it comes to extraterrestrial repairs, stick to duct tape: liquid glues don't work in zero gravity.

要讓火箭升到太空，膠水可能是不可或缺的，但如果要在地球以外的地方維修，你就要用布膠帶：液體膠水在無重力空間不管用。