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How to Make Silly Putty to Demonstrate Chemical Reactions

Learn how to demonstrate chemical reactions using homemade silly putty with the instructions in this Howcast science project video.


You know what I like? I like inventions. I mean, think about it. A cell phone, that was an invention. It didn't exist 50 years ago. An air conditioner, that was an invention. A light bulb, that was an invention. But you see, all of those inventions, the person who created them had that idea in mind, and they were successful, but sometimes inventions are created accidentally. This experiment, actually was an accidental invention.

In the '40s, during World War II, America needed rubber. We just really needed a lot of rubber. And people were donating a lot of old tired but it just wasn't enough rubber. So what happened was, people were asked, scientists were asked, and engineers. Now engineers design stuff, right? Now they were asked to create a synthetic rubber. So a man went out, created a synthetic rubber, thought it was great, but unfortunately, it didn't have the properties that rubber needed to be.

Now remember, properties are things that you could describe something about. For instance, it's texture, it's size, it's hardness. Well, he had the synthetic rubber, and it just wasn't right. So what he did was, he kind of passed it around and gave to his friends and brought it to parties, and he became known as like, this nutty putty. It just caught on fire, and people loved it.

He then sold it as a children's toy. Maybe it wasn't practical at the time, but the end result was an accident. And here we are 60, 70 years later. People are still buying silly putty today. Now the cool part about it is, you do not need to go buy it when we can make it. Now some of you are going to say, 'Carmelo, we don't have these experiments at home. We don't have these materials at home,' but the reality is, you have most of the materials at home. And you probably are just going to have to buy one thing, for maybe, not even, $2. So this is experiment is going to cost you less than it would cost you to go buy it in a children's store. And you can make tons of it, enough to cover this entire table.

Now, watch this. All I need is water, water that I'm just going to fill up this container with. Okay? The material that you probably don't have, is this powder. Now you can find this in the laundry section in any grocery supermarket store. It's called Borax powder. It a laundry booster. This is the key ingredient to making silly putty. I think we should make something called a saturated solution. Now, you probably don't know what a saturated solution is, right? But let me explain something to you. If you had a cup of water and you put a teaspoon of sugar in the water, and you stirred it around, what happens to the sugar? It dissolves. If you put a second teaspoon, it dissolves. Ten teaspoons, it dissolves. By the 20th teaspoon, you see, it's dissolving, it's still water, you just can't see it. But ultimately, the water could only hold so much of the sugar. It's not going to be able to dissolve anymore. By the 21st teaspoon, I'm just making that up, I don't know the actual number, eventually you'll stir, but the sugar will no longer dissolve and it sinks to the bottom. Now we made a saturated solution. Saturated means the water can not hold anymore of the sugar.

Now we're not using sugar. We're going to make a saturated solution of Borax powder. So I'm going to put a bunch of Borax powder in here, Okay? The saturated the solution, the better your silly putty will be. And I'm going to stir this around, and you're going to notice when I stop stirring there's still going to be some powder left at the bottom of my pitcher, and that's perfect because that means that the water is no longer able to dissolve anymore of the powder. So 30 seconds later, or 60 seconds later, stop the stirring. All of the Borax powder that was not able to dissolve is going to settle to the bottom, sort of like sand in the ocean, right? Sand doesn't dissolve. Well, now the Borax can no longer dissolve because there's too much already dissolved within the liquid. That's my saturated solution.

Now, what's step 2? I'm going to take a cup, and I'm going to take a spoon, and now, I'm going to use regular water, Okay? Doesn't matter, the temperature, it just matters that it's regular water. Now, you want to use a one to one ratio. So if I use one teaspoon of water, then my second ingredient is going to be glue. So if I make one teaspoon of water, I put one teaspoon of glue. If I want to make it bigger, so one to one ratio, it's equal amounts, four teaspoons of water equals four teaspoons of glue.

I'm going to start with my water. Let's count together. That's one teaspoon, that's two, that's three, that's four, I'm going to put five teaspoons. And that's five. Now I'm going to start with the glue, Okay?

Now glue is very viscous. It's very thick. It's going to take some time for you to do this, but you've got to make sure that your measurements are accurate. So it's one teaspoon. If you want you can use a stick or another spoon to scrape it off so you're getting the entire teaspoon down. This is going to be teaspoon number two. Remember in science, measuring is so important. You've got to be accurate.

Okay, guys, so what I did was, I put my five teaspoons of glue, and my teaspoons of water, and you're going to notice, all the glue went to the bottom. It's more dense, there's more matter in the glue than there is in water, but that's another lesson. Now what I want to do is make a mixture. And a mixture is when you mix two or more things together. So I'm going to take my stick and I'm going to mix glue and the water. I'm making a weaker version of glue. It's a diluted glue. Four teaspoons of water or five teaspoons of water, and five teaspoons of glue. If you wanted to make it smaller, you could make one teaspoon of water and one teaspoon of glue. Now, we can make this experiment even more fun.

If anybody you live with is a cook, chances are, in your pantry or somewhere in your house, you have food coloring. How cool would it be if you could make your silly putty any color you want? Maybe you could make it green and look like a giant boogie. Okay? Yeah, let's do that.

So I'm going to make it green. I think three is good. We'll go one, two, three. Now, I'm going to pick it up, and it's so important to take your time to stir, because, as you notice, it's going to take a few seconds for the food coloring. I like to scrape the sides of the cups, stir it all around, take your time. It's not a race. The slower you go, the better your silly putty will be.

Now, if you notice, some of you are going to say, 'Wait a second. It doesn't look like silly putty. It's just a liquid.' Because that's all it is right now. Silly putty has not been created yet. But that's where your Borax solution comes in. You see, this is going to be my main ingredient. When I pour this, and I'm just going to pour it in the cup, because I'm going to need a couple of teaspoons of it, right? Now remember, this is a saturated solution. If you notice, the bottom of the container still has a lot of Borax powder, and it is exactly how I want it. But you see, this is the hard part. I don't know, I just have no clue, how much of this is going to be needed in this, to make my silly putty work.

So what I do is, I'm going to add one teaspoon at a time. I'm going to add a teaspoon in, and there's going to be a really cool chemical reaction. A chemical reaction is when you mix two chemicals together and something new is made that wasn't there before. And that's what we're about to do. So I'm going to take a teaspoon, and pour it in. I'm going to stop and I'm going to stir. And as you start to stir, there's a chemical reaction. And then you when you pick up your stick, ooh, giant boogie. Achoo! No, it's not a boogie, but it's silly putty. But look, there's still a lot of liquid left. So that means, the more Borax solution I put into here, the bigger my silly putty will be. And, once there isn't any liquid left, you know you need to stop adding your Borax solution.

So this is teaspoon number two. And you're going to notice on the stick, your silly putty grew. Now look in the cup. There's still a little more liquid left. So, obviously, I'm going to add one more teaspoon. And this is teaspoon number three. Stop, take the stick and stir, and you're going to notice that, it, just, is, it, oh, okay. I think the silly putty's ready. And you're going to nice now, it's a huge, wet, giant batch of silly putty.

Well now, this is the fun part. I'm going to pick up the silly putty. I'm going to grab it off the stick, and it just feels gross and disgusting, and it's wet. It feels like I just picked my nose again. I'm going to take it.

Now, it's going to be wet at first. It's going to be like you're a baker making dough for pizza, or for bread. So I'm going to just press it. Actually, you know what? I'd like to say this, ready? I'm going to put it on my hand, and I'm going to say, press it, then I'm going to say, roll it, then I'm going to knead it, and I'm going to keep doing that process, Okay? Press it, roll it, and knead it. Do it again. Press it, roll it, and knead it. Do it again. Say it with me, 'Press it, roll it, knead it,' and then you keep doing it until, eventually, my silly putty is done.

Check this out. It actually bounces. I could roll it into a ball, I can tear it, I can pull it, I can stretch it. Guys, I just made a synthetic rubber, a cool chemical reaction, and all I needed was water, glue, and that really cool Borax powder that, again, you can get at any grocery store.

I just made silly putty.

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