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  • Why does my bottled water have an expiration date? Does this stuff actually go bad?

    我的瓶裝水為什麼有保存期限?水真的會壞嗎?

  • Hi, everyone, Julian here for DNews.

    各位好,我是 DNews 的 Julian。

  • Have you ever left a glass of water out overnight, and the next day, taken a drink, and noticed it tasted funny?

    你是否曾經把一杯水放到隔天,然後喝一口時卻發現味道怪怪的?

  • Does that mean the water is going bad, or what's happening here?

    這是不是代表這杯水壞了,還是發生了其他狀況?

  • Well, the water itself doesn't have any sugars or proteins like food, so microbes aren't consuming it and rotting it.

    水並不像食物般含有糖或蛋白質,所以微生物無法在其中滋生並使其腐壞。

  • However, that's not to say the chemistry of the water hasn't changed.

    但這並不代表水的化學性質沒有改變。

  • By being exposed to air, the water absorbs some CO2, and a tiny portion of that, about 0.13%, is converted into carbonic acid.

    水暴露在空氣中時,會吸收一些二氧化碳,而其中的一小部分,大約 0.13%,會轉變為碳酸。

  • Some carbonic acid will then lose a proton or two, forming bicarbonate or carbonate respectively.

    部分碳酸會失去一到兩個質子,分別形成碳酸氫或碳酸鹽。

  • This lowers the pH of water, making it slightly acidic and changing the taste.

    這使得水的酸鹼值降低,讓它呈現弱酸性並且有味道的改變。

  • So, does that mean it's unsafe? Probably not, no, unless you are a shellfish.

    那麼這意味著水已經不安全囉?其實並不是,除非你是貝類生物。

  • Carbonic acid forms about 4 million times more bicarbonate than carbonate, and shellfish need carbonate to build their shells.

    碳酸形成碳酸氫鹽的能力比碳酸鹽高出四百萬倍,而貝類需要碳酸鹽來生成牠們的殼。

  • The bias towards bicarbonate production means they have less to build their shells from.

    而碳酸轉換成碳酸氫鹽的傾向意味著貝類將會缺少形成貝殼的原料。

  • Not only that, but the higher acidity can actually dissolve shells.

    不僅如此,酸性提高還可能會溶解貝殼。

  • Since the Industrial Revolution, the ocean surface has become slightly more acidic.

    自從工業革命以來,海水表層酸度已經小幅度地提高。

  • So, if you love oysters, there's another reason to care about CO2 in the atmosphere.

    所以說,如果你愛吃生蠔,你又多了關注大氣中二氧化碳含量的理由了。

  • Anyway, if you're a human, the small shift in pH isn't going to be what hurts you.

    言歸正傳,你身為人類,小幅度的酸鹼變化對你沒有傷害。

  • The problem is water in an unsealed container has been exposed to bacteria.

    問題是,裝在未完全密封容器中的水暴露於細菌威脅之中。

  • Most tap and bottled water has chlorine additives, which will keep the microbes from multiplying for a day or two, but after that they can go crazy.

    大部分自來水或瓶裝水都會添加氯化合物,在一兩天內阻止微生物過量滋生,但在那之後,可能就會失控。

  • Water left outside can also start growing algae and host mosquito larvae, which will make you sick and is gross to think about,

    曝露在空氣中的水也可能會滋生藻類以及孑孓,可能會使你生病,而且光想就覺得噁心,

  • but not as gross as thinking about the dust inside your house landing in your water.

    但這噁心程度遠不及想像懸浮在屋內的灰塵落在你的水中。

  • It can be purified with chemicals, like iodine or chlorine, or it can be filtered and boiled, and it'll be good as new.

    當然,我們可以用碘或氯等化學藥劑來淨水,也可以採用過濾和煮沸的方式,讓水再次純淨。

  • Again, it's not the H2O breaking down and going bad, it's just hosting other nastiness that spoils the taste.

    再強調一次,這並不是水本身被分解腐壞,而是水中含有讓味道變怪的髒東西。

  • Our ancestors didn't have the benefit of germ theory or chemical purification, so when their water became unsanitary, they had to come up with a different solution.

    人類的祖先沒有菌源說和化學淨水的知識,所以當他們的水變得不衛生時,他們得想出其他的解決方法。

  • When they set out for long voyages, Europeans sailors had stores of water in wooden barrels.

    當歐洲的水手要展開長途航行時,他們將水儲藏在木桶中。

  • After a few weeks though, it would start to grow algae. So to get around this, sailors also brought along beer.

    但幾週過後,藻類便會開始在水中生長。為了解決這個問題,水手們還會帶上啤酒。

  • And when that beer ran out, they switched to that old pirate favorite, rum.

    當啤酒喝完時,他們改喝海盜的最愛:蘭姆酒。

  • The alcohol in the beer and rum killed off bacteria, but the side effect was drunken sailors early in the morning.

    啤酒和蘭姆酒中的酒精可以殺死微生物,但副作用是,一大清早就醉醺醺的水手。

  • In fact, British sailors actually got a daily rum ration until 1970.

    實際上,英國水手截至 1970 年以前,每日都有蘭姆酒配給。

  • Now, though, we can store water indefinitely without having to worry about its safety, provided it's stored correctly.

    如今,我們可以無限期地儲水,而不用擔心水的飲用安全性,當然前提是,水的儲藏方法要對。

  • The CDC says commercially bottled water is the safest, but it should still be stored out of direct sunlight.

    疾管局表示,市售瓶裝水是最安全的,但它仍必須被儲藏在不被陽光直射的地方。

  • Some plastics release a hormone disruptor called bisphenol-A, or BPA, into the water when heated.

    有些塑膠製品受熱時,會將賀爾蒙干擾素酚甲烷(簡稱 BPA)釋放到水中。

  • Plastic bottles are also permeable, so water should not be stored near pesticides or gasoline.

    同時,塑膠瓶是會被溶解的,因此它們不應該被儲藏在靠近殺蟲劑和汽油的地方。

  • Aside from that, though, you don't have to worry about the expiration date on bottled water.

    除了以上情形,你大可以不用擔心瓶裝水上的保存期限。

  • That's a holdover from old New Jersey law that has since been repealed because there's no scientific evidence to support it.

    這只是紐澤西的一條舊法令罷了,它現在已經被廢止,因為沒有足夠的科學證據支持。

  • Gotta love it when science informs lawmaking!

    當科學影響立法時,真是大快人心!

  • So, now the question is, how much water do you actually need to drink?

    所以現在的問題是,你究竟需要喝多少水?

  • Trace covers that here.

    Trace 在連結影片中會為各位說明。

  • A lot of our fluid intake comes from food. The rules say that we need to drink fluid.

    我們很多的液體攝取來源都是食物。常規告訴我們要多喝水。

  • So, if we eat a banana or an orange, we consume their fluid, which is to say, we take their water.

    所以如果我們吃一根香蕉或是一顆橘子,我們會攝取它們的液體,也就是說,我們搶了它們的水分。

  • Have you gotten sick from drinking water? Did you switch to rum? Or do you have any other questions that you want us to field?

    你是否曾經因為喝水而生病?你改喝蘭姆酒了嗎?還是你有其他想要我們回答的問題?

  • Let us know in the comments or on Facebook or Twitter.

    請在底下留言,或是在臉書或推特告訴我們。

  • Subscribe for more, and I'll see you next time on DNews.

    請訂閱以收看更多影片,我們下回 DNwes 再見。

Why does my bottled water have an expiration date? Does this stuff actually go bad?

我的瓶裝水為什麼有保存期限?水真的會壞嗎?

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B2 中高級 中文 美國腔 儲藏 蘭姆酒 水手 貝類 微生物 瓶裝水

水會過期嗎? (Does Water Ever Expire?)

  • 94557 4337
    Jeng-Lan Lee 發佈於 2017 年 08 月 10 日
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