But the history of fireworks isn't all hugs and celebrations.

但是煙火的歷史可一點也不喜慶。

Long before epic fireworks displays, chemists in China invented the key ingredient that propels those bright lights into the sky. That invention was what we now call gunpowder.

遠在人們開始有煙火秀以前，中國的化學家發明了讓煙火沖上天際不可或缺的一樣原料，那就是火藥。

Our story begins back in ancient China in the mid-ninth century where early Chinese alchemists were trying to create a potion for immortality.

今天的故事源起於西元九世紀中段的古代中國，當時中國的煉丹師各各都希望能研究出長生不老藥，

Instead, what they created was a flammable powder that burned down many of their homes.

但是，他們創造出的，卻是種易燃的粉末，而且還把許多術士的家給焚毀了。

They quickly realized that this black powder, which they called fire medicine, was precisely the opposite of something that would make you live forever.

煉丹師很快就發現，這種被他們稱做「火藥」的黑粉，不但不會讓人長生不老，反而是會讓人提早往生！

In these early days, the Chinese hadn't yet figured out how to make the powder explode; it was simply very flammable, and their armies used it to make flaming arrows and even a flamethrower.

在早期，當時的中國人還未研發出讓火藥爆破的方法，他們只知道這種粉非常易燃，而軍隊就拿火藥來製作會燃燒的箭還有噴火器。

But once they figured out the right proportions of ingredients to create a blast, they began using the powder even more,

但是當他們研究出能造成爆破的正確的配方後，火藥的應用變的非常頻繁，

creating fireworks to keep evil spirits away and bombs to defend themselves against Mongol invaders.

從驅趕妖魔的爆竹到用來抵抗蒙古人入侵的炸彈。

It was these Mongols, most likely, who spread the invention of gunpowder across the world.

火藥會流傳到西方世界很有可能是因為蒙古人。

After fielding Chinese attacks, they learned how to produce the powder themselves and brought it with them on their conquests in Persia and India.

在阻擋下中國的攻擊之後，他們學會如何自行生產這種粉末，並將其運用到波斯和印度的征戰中。

William of Rubruck, a European ambassador to the Mongols, was likely responsible for bringing gunpowder back to Europe around 1254.

而一位叫 William of Rubruck 的歐洲駐蒙古大使，很有可能就是他在 1254 年把火藥被帶進歐洲的。

From there, engineers and military inventors created all kinds of destructive weapons.

此後，工程師及軍火發明家研發出了各式各樣的毀滅性武器。

From bombs to guns to cannons, gunpowder left its mark on the world in some pretty terrible ways, in contrast to the beautiful marks it can leave in the air.

從炸彈、槍，到大砲，火藥以挺駭人的方式在世界上留下了痕跡，跟那些在天空綻放的美好光景。

So, how does black powder propel fireworks into the sky?

話說回來，到底火藥是怎麼把煙火推上天際的？

You might have seen old Westerns or cartoons where a trail of gunpowder is lit and it leads to a large and obviously explosive barrel. Once the fire gets to the barrel, a large boom occurs.

你或許在老西部電影或是卡通裡看過這個場景，有人點燃一條用火藥灑出來的藥引，然後那條線會接到一個裝滿火藥的桶子，一旦火燒到木桶，你就會聽到砰然巨響。

But why doesn't the trail itself explode?

但為什麼那條藥引不會爆炸？

The reason is that burning the powder releases energy and gases. While the trail is burning, these are easily released into the surrounding air.

原因就是，藥引在燃燒時產生的能源和氣體，會在燃燒時被釋放到周圍的空氣中。

But when the gunpowder is contained within the barrel, the energy and gases cannot easily escape and build up

可是當火藥裝在桶子裡時，能源與氣體便無法被釋放，在累積到某種程度後...

until BOOM!

砰!

Firework canisters provide a single, upward-facing outlet to channel this explosive energy.

煙火統提供這個有爆發性的能源，一個朝上的出口。

The wick ignites the gunpowder and the energy takes the easiest exit from the canister, launching the firework high into the sky.

火藥被藥引點燃後產生的能源會以最容易的方式離開煙火筒，把煙火送上天際。

The flame then makes its way through the firework's encasing and the same reaction occurs high above our heads.

同樣的化學反應還會在高空產生一次，當火苗在高空點燃包在發射筒裡的第二組火藥時，煙火就會在天空中綻放。

So, while the Chinese alchemists never found the compound for eternal life, they did find something that would go on to shape all of civilization,

雖然中國古代的煉金術士最終沒有研究出長生不老藥，他們的發現變成了世界史中重要的轉捩點，

something that has caused many tragic moments in human history, and yet still gives us hope when we look up in celebration at the colorful night sky.

也造成了歷史上無數悲劇，卻又在節慶時賜予了我們夜空中綻放絢爛色彩的希望。