這是英文原版

Hi, I'm Sandy from Science World and today I'm going to show you a chemistry experiment that you can do at home. Now I've found a bunch of chemicals in my kitchen and in my bathroom and I want to know whether these things are acids or bases. How do I figure that out? What I need is an indicator, which sounds pretty fancy, but you can make an indicator out of something as ordinary as purple cabbage. I cut up a purple cabbage and added a bunch of hot water and I've got what I fondly refer to as cabbage juice. As you can see, it is this beautiful purple color. That's because it contains a pigment called anthocyanin that makes most purple and blue plants purple or blue. Anthocyanin is neat because it changes color depending on whether it's in an acid or a base. So let's take lemon juice. Acid or base. Some lemon juice into the graduated cylinder and I'll add a little bit of my cabbage juice. It turns pink. Lemon juice is an acid and in an acid, anthocyanin is going to turn red or pink. What have I got next? I've got ammonia. Now, ammonia is not something you want to play with without an adult's permission. It's pretty strong stuff. I'll put just a tiny bit into my cylinder. Now let's see what happens. Here is an acid，The cabbage juice will turn red, but here we've got something completely different happening. Our cabbage juice is turning green. That tells us that ammonia is a base. Actually, ammonia is a very strong base and bases are often used in cleaning products. The next thing I have here is soap and water. That sounds like a cleaning product. Let's see whether it's an acid or a base. Soapy water into the cylinder and we'll add the cabbage juice. Now it looks to me like this soap isn't actually changing the color of the indicator at all, which means that it's neutral. It's neither an acid nor a base. Probably healthy if you're going to put it on your skin. What else have I found here? Some vinegar. Now, you think vinegar is more like lemon juice or more like ammonia? Probably having gas. We'll put vinegar into this container and we will add some cabbage juice indicator. So what's that most like? Just like lemon juice, vinegar is in fact an acid. The last product I found is baking soda and water. If you've ever mixed baking soda and vinegar together, you know that baking soda and vinegar do something. One of the reasons you might want to know whether you have an acid or a base is to predict what kind of chemical reaction you might have. So I'm going to add some cabbage juice to the baking soda and water and we will see that that is definitely basic, sort of like the ammonia. So there we go, with simply the anthocyanin that's inside purple cabbage leaves, we are able to make an indicator that can tell the difference between acids, bases and neutral substances. Now, at Science World, we have the opportunity to use some slightly fancier indicators. In a moment, we're going to try and experiment with bromothymol blue. At Science World, we have access to special indicators like bromothymol blue. So this is an indicator that we can use to indicate an acid actually. So I'm going to put some in this giant container of water and we'll see what color it looks like. Now, despite its name, bromothymol blue actually looks clean when it's in a neutral or in a basic solution. And we want to see what it looks like in an acid. So we have to somehow make this liquid into an acid. The easiest way I know how to do that is to make it into carbonic acid by dissolving carbon dioxide in the water. And the best way I know to do that is to blow bubbles in this giant, earth-fired glass. Blow some bubbles, dissolve some carbon dioxide, make some carbonic acid, and let's see if we can make the indicator change color to indicate that we have an acid. Starting to see something happen, so that's my carbon dioxide that I'm producing, dissolving in the water, and changing the color of the indicator by turning the water into carbonic acid. That's bromethyme blue, despite its name, green in a neutral solution, and yellow in an acid like this carbonic acid solution from my breath.

這是中文翻譯

嗨，我是來(lái)自科學(xué)世界的桑迪，今天我將向您展示一個(gè)可以在家中進(jìn)行的化學(xué)實(shí)驗(yàn)?，F(xiàn)在我在廚房和浴室找到了一些化學(xué)品，我想知道這些東西是酸還是堿。要弄清楚這一點(diǎn)，我需要一個(gè)指示劑，聽(tīng)起來(lái)很高級(jí)，但你可以用普通的紫甘藍(lán)制作一個(gè)指示劑。我切碎了一些紫甘藍(lán)，加了一些熱水，得到了我們稱之為紫甘藍(lán)汁的東西。正如您所看到的，它是一種美麗的紫色。這是因?yàn)樗幸环N叫做花色素的色素，使大多數(shù)紫色和藍(lán)色的植物呈現(xiàn)紫色或藍(lán)色?；ㄉ睾苌衿?，因?yàn)樗鼤?huì)根據(jù)所處的酸性或堿性而改變顏色?，F(xiàn)在我們來(lái)看看檸檬汁。酸性還是堿性？我將一些檸檬汁倒入量筒中，然后加入一點(diǎn)紫甘藍(lán)汁。它變成了粉紅色。檸檬汁是一種酸，在酸性環(huán)境中，花色素會(huì)變成紅色或粉紅色。接下來(lái)是氨水?，F(xiàn)在，氨水不是您沒(méi)有成年人許可就可以玩的東西。它是相當(dāng)強(qiáng)力的物質(zhì)。我只加入了一點(diǎn)點(diǎn)到量筒中?，F(xiàn)在我們來(lái)看看會(huì)發(fā)生什么。這里是一個(gè)酸，紫甘藍(lán)汁會(huì)變紅，但這里發(fā)生了完全不同的反應(yīng)。我們的紫甘藍(lán)汁變成了綠色。這告訴我們氨水是一種堿。實(shí)際上，氨水是一種非常強(qiáng)的堿，堿經(jīng)常用于清潔產(chǎn)品中。下一個(gè)是肥皂和水。聽(tīng)起來(lái)像是清潔產(chǎn)品。我們來(lái)看看它是酸還是堿。將肥皂水倒入量筒中，然后加入紫甘藍(lán)汁。現(xiàn)在看起來(lái)好像這個(gè)肥皂實(shí)際上沒(méi)有改變指示劑的顏色，這意味著它是中性的，既不是酸也不是堿。如果你要把它涂在皮膚上，這可能是健康的。我還找到了一些醋。你認(rèn)為醋更像檸檬汁還是氨水？可能會(huì)產(chǎn)生反應(yīng)。我們將醋倒入容器中，然后加入一些紫甘藍(lán)汁指示劑。那個(gè)結(jié)果最像什么？就像檸檬汁一樣，醋實(shí)際上是酸性的。我找到的最后一個(gè)產(chǎn)品是小蘇打和水。如果你曾經(jīng)將小蘇打和醋混合在一起，你就會(huì)知道小蘇打和醋會(huì)發(fā)生反應(yīng)。了解您是否有酸性或堿性物質(zhì)的一個(gè)原因是為了預(yù)測(cè)可能發(fā)生的化學(xué)反應(yīng)類型。因此，我將在小蘇打和水中加入一些紫甘藍(lán)汁，我們將看到它肯定是堿性的，有點(diǎn)像氨水。這樣一來(lái)，我們只需使用紫甘藍(lán)葉中的花色素，就能制作出一個(gè)可以區(qū)分酸、堿和中性物質(zhì)的指示劑。在科學(xué)世界，我們有機(jī)會(huì)使用一些稍微高級(jí)的指示劑。接下來(lái)，我們將嘗試使用溴甲藍(lán)進(jìn)行實(shí)驗(yàn)。在科學(xué)世界，我們可以使用溴甲藍(lán)等特殊指示劑。實(shí)際上，這是一種可以用來(lái)指示酸性的指示劑。我將一些溴甲藍(lán)放入這個(gè)巨大的水容器中，我們將看到它的顏色是什么樣子的。盡管它的名字是溴甲藍(lán)，但在中性或堿性溶液中它實(shí)際上看起來(lái)是干凈的。我們想要看看它在酸性溶液中的表現(xiàn)。所以我們必須以某種方式使這種液體成為酸性的。我知道最簡(jiǎn)單的方法是將它轉(zhuǎn)化為碳酸。通過(guò)將二氧化碳溶解在水中。而我所知道的最好的方法是在這個(gè)巨大的陶瓷玻璃中吹泡泡。吹一些泡泡，溶解一些二氧化碳，生成一些碳酸，讓我們看看是否能讓指示劑改變顏色，表明我們有一個(gè)酸性溶液。開(kāi)始看到一些變化，那是我產(chǎn)生的二氧化碳溶解在水中，通過(guò)將水轉(zhuǎn)化為碳酸，改變了指示劑的顏色。這就是溴甲藍(lán)，在中性溶液中是綠色的，而在酸性溶液中（比如我呼出的碳酸溶液）是黃色的。