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Colorful Chemistry of Acids and Bases

Feb 22, 2020
Let me show you a magic trick. It may look like a normal teapot, but it is a magical teapot. And it's magical because it will pour any color you ask it to. You do not believe me? Look at this. Pink. Hey, it's not bad. Okay, blue. Red. OK. How about green? No no no. I mean, yellow. And it's OK. And then green. So here we go. A rainbow of colors. So I bet you're wondering how I did that. Well, it's not magic. But it's a pretty interesting science. My name is Tyler and I am a student at MIT.
colorful chemistry of acids and bases
And I'm going to teach you the science behind this magic trick. And I'm going to show you how you can do it yourself at home. But first we have to go to the laboratory and learn a little about some chemicals called

acids

and some chemicals called

bases

. So let's go and check it out. Welcome to my laboratory. This is where I have all the chemicals that I use for these science experiments that I do every day. And I also brought some of these chemicals from home. I also have a bunch of beakers here and I filled them with a liquid called an indicator.
colorful chemistry of acids and bases

More Interesting Facts About,

colorful chemistry of acids and bases...

You can see that the indicator, this indicator that I'm using, has a kind of purplish blue color. And that's going to be important. The indicator tells us if a chemical substance is acidic, basic or neutral. Let me show you what I mean. I'm going to take a chemical and add small drops to the indicator. Look, these drops create a very light purple color. And there's some pink, and some more pink, and it gets pinker and pinker the more I add. And now it gets darker and darker, and finally I get a very deep, bright red. Isn't it great?
colorful chemistry of acids and bases
If we can add a chemical to this indicator, and it makes it redder and redder and redder (it starts with purple and goes to pink and then red), we call it acid. So this chemical here is an acid. Let's take a look at another example. Here's a new indicator glass. And again, you can see it starts out as a very light blue, purple color. Now I'm going to take this other chemical and add it to the indicator. Let's see what happens now. You can see little bits of green on the gauge when I start putting this in.
colorful chemistry of acids and bases
Now we move on to a very beautiful blue color, a very bright blue. And then it becomes kind of aquamarine here, getting greener and greener. And now the indicator turns green. And I'll show you what happens if we add even more. This becomes more and more yellow, until you have a yellow solution. And it's a really bright, fresh yellow color. If we can add a chemical to an indicator and it turns it darker blue, or that brighter blue, that really pretty blue, and then greener, and finally yellow... if it can produce any of those colors when we add it to the indicator -- we call it base.
So the

acids

make it pink and then red. And the

bases

make it blue and then green and then yellow, if we add a large amount. OK. Let's look at another example. I have a third chemist here. I'm going to add a little bit, dropping it here, lots of drops. And I don't really see any changes. The color remains the same. And as you'll see, I can add as much as I want and the color will still be this blue and purplish color. This is because we call this compound, this chemical substance, neutral. It is neither acid nor base.
So the color of the indicator does not change. We can add as much as we want and the indicator will remain the same color. So those are our three categories of chemicals: acids, bases, and then those that are neutral. You can tell if something is acidic, basic or neutral by the color which is an indicator. You might think this indicator is some fancy chemical that you would only have in a lab, but I actually made this indicator in my kitchen at home. And you can do the same. We will need some indicator of the magic trick we are discovering.
And I'm going to show you how to make this type of indicator in your kitchen. So let's take a look at that. Well, here we are in my kitchen. And I want to show you how to make this acid-base indicator that we've been using so you can do these color changes yourself so you can do the magic trick. So I will say this is pretty easy, but you will have to boil some water and use a stove. So make sure you have an adult nearby to help you with that step. Here's what you're going to need.
First of all, you will need a red cabbage. You should be able to find something like this in any supermarket. And then you'll need a pot to boil some water. And then you will need a strainer. And that is. It's pretty simple. So what you want to do is take the pot and fill it halfway with water. And then you want to take the cabbage and start removing parts of the leaves and putting them in the pan. And you need to fill it until almost all of the cabbage is covered with water. So this is a pretty good amount around here.
And then what you want to do is turn up the heat and boil water. Let it boil for four or five minutes. And then turn off the heat and let it sit for 15 minutes, 10 to 15 minutes. And after doing that, what you will see is that the cabbage will lose its color. All that purple dye that was in the cabbage leaves is going to come out into the water. And you're going to finish with red cabbage juice. And then the last thing you want to do is take this and using a strainer, pour the juice over the top.
And now you have the cabbage juice indicator ready to go. Let's go see what we can do with this indicator and then find out how we can do this magic trick. Okay, now that you've made your cabbage juice, you're ready to start testing things around the house to see if they're acidic, neutral, or basic. and watch those cool color changes. I have here by my side some examples of things you can try at home. But really anything that's liquid or powder, you should be able to try it. Just check with your parents first to make sure you're not using anything that's dangerous or toxic or anything like that.
So okay, everything with them first. But let's do a quick example here. Let's say you want to try some glass cleaner here. You can spray just a little bit into the bottom of a glass and then add the indicator. Oh. It turns sort of a bluish green, so we know it's a base. Or let's say we wanted to try some hot sauce here. Add some hot sauce, a couple drops in there. And then all we have to do is add a little bit of the indicator. Oh, and we get a nice red color, kind of a pinkish color.
So we know this is an acid. Now let's talk about the magic trick. So how did I do it? Well, you may have been discovering parts of it. I brought my teapot here. And I filled it with indicator. An indicator, as you know, changes color depending on whether I add an acid or a base. So what I did was I took glasses like this and I added a little bit of acid or base to the bottom. I tried to find clear liquids that were acids and bases. So let's do an example here. Let's say you wanted a red color.
What I do is I take a little bit of vinegar, and I would use vinegar because I know that vinegar is an acid, so it will give me a red color. I add a little bit of this here in the background. Now, if you are doing this magic trick, you will be able to see the clear liquid at the bottom. But trust me, no one else will, especially if you make sure they keep a little bit of distance, especially if you're using clear glass, clear glass like this, they won't be able to see it if you have it on a table.
Then you say they are empty or you don't say anything at all and people will assume they are empty. And then you go ahead and grab your teapot or your gauge jug and pour it in. You will get a nice red or pink color. OK. So there is a wide range of colors you can get. You can get reds and you will get pinks, blues, purples and greens. And what I want you to do is experiment to find out which of these chemicals in your house give you these different colors. And then put a little bit of that chemical that gives you the color in the background.
And pour the indicator to get that color. Now you may discover that different amounts of these chemicals give you different colors. So maybe a little glass cleaner will give you a bright blue, but a little more glass cleaner will give you a green. So experiment with all these things. But there is one thing I do want to tell you. You can get a very pretty yellow color by using a little bleach. But bleach can be dangerous, so be sure to work with an adult if you're doing this. Put a few drops of bleach in the bottom of a glass like this, add a little bit of indicator and it turns green and then turns yellow.
And that's how I did that at first when it started green and then turned yellow. So I hope you enjoyed watching this video. We learned a little about acids and bases. We learned about indicators. And we learned how to do this cool magic trick that you can now use to impress your friends and family.

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