What is the difference between a solid, a liquid and a gas?
Solids, liquids and gases. The states of matter. Now that's a really neat topic. When you start thinking about solids, liquids, and gases, most of us know what they are. If I mention a brick, you'd say, "solid". If I mention chocolate milk, you'd say, "liquid". I mention helium, you'd say, "gas". However, sometimes things are really kind of mixed up. If you think about ice cream, is it a solid, liquid or gas? You know, when I buy it I want it to be a solid, but it can change. So, states of matter: you could have water as a liquid, you could have it as a solid, you could have it as a gas, and it changes depending upon the temperature. Now, one of my favourite things to use when I'm talking about solids, liquids and gasses is dry ice. Dry ice is really, really cold. In fact, it's colder than where I'm from. It is a hundred and nine degrees below zero. It is so cold. Now, it is a very strange substance, too. In fact, what is it called? It's called dry ice. It's made out of carbon dioxide, but it's got its name from the fact that it never melts. It never, ever melts. It goes from a solid directly to a gas. It doesn't melt, which is kind of neat. Now, since it's going from a solid to a gas we can show you some things with it. At a hundred and nine degrees below zero, I'm wearing gloves. I'm not going to touch it, because my hands could freeze to it. Now, this is a small piece of solid carbon dioxide. The carbon dioxide is a gas, and you can see a little bit of the smoke coming off. It's really not smoke. This is so cold it's actually forming a little cloud here. It's condensing the water that's in the air, and it's turning from a solid to a gas, and all sides of it are doing that. The top is, the bottom, the front, the back. So, if I set it on the table it's actually creating itself a little bit of lift, almost like an air hockey table. There's air blowing up from the bottom of the air hockey table and it lifts the puck up so it floats and it moves really fast. Well, this is doing that too, and I have to just slide it around a little bit; look! It is floating on its own layer of gas, just like an air hockey puck. So, it's turning from a solid into a gas. Now, we can show you some other things that work with this, too. I'm going to need a hammer. Now, I'm going to take this hammer and I'm going to take and make some of this dry ice into a little pulverized state. Let me just hit some of this, crushing it up into almost rice size grains, and then I'm going to try and scoop up a little bit of this material, and then we'll take a spoon and we're going to add some of the dry ice to the balloon. We'll just put some in there. In fact, this could even be called a science for lazy people, because I'm very lazy and once I get some dry ice in here and tie a knot in this end, it's going to start to do exactly what I want it to do. When I tie a knot in there... can you see that balloon? It's actually getting bigger and bigger because the solid carbon dioxide, the dry ice, is turning into a gas. Now, this balloon will continue to blow up as long as there's dry ice in here, and this will get bigger and bigger as we just let it sit. It's turning from a solid into a gas, and the gas that's in there is carbon dioxide. There's a lot in there, yet, so it's going to get bigger. Now, I can show you a couple of other things. On an old quarter there's an animal on the back, and that happens to be an eagle. Now, if I take this eagle and I put it on the dry ice, it will make the sound of an eagle. Listen! Did you hear that? Sounds just like an eagle. Try it again! What's happening is that the eagle's not making that sound, but what's really happening here is that the dry ice, turning into a gas, is causing this quarter to vibrate. Now, I don't know if you noticed when I started, but I held this in my hand a little bit to warm it up. Warm objects make the carbon dioxide turn from a solid to a gas faster, so when I set this down on there - I'm going to use my hand to show you this - if my hand is dry ice, and I push down on there, underneath that warm quarter, the gas is turning into a gas faster because it's warm, and it rises up, and I'm pushing down. The gas pushes up, and I'm pushing down. Well, this is happening very, very, very fast, and when it goes fast enough it actually vibrates. One more time. Oh, and look what I noticed! This side of the hammer is about the size of a quarter. Now, if we set this down on there, this might just make sound. Instead of hitting it, I'm going to set it on there. Listen! So, it's vibrating! It's also vibrating. I would like to show you that we can make a big cloud with carbon dioxide. Now, if we can get this dry ice to turn into a gas faster, it would give us a lot more cloud, and one of the ways that it actually makes a cloud is with moisture. Now, to cover both bases - to have this turn into a gas faster - we need heat, and we need moisture. In this container I have hot water. So I'm going to take the hammer and make some smaller pieces, not real tiny, just break it up into some chunks, and then we'll take these pieces and put them in here, and we will make a cloud. Ho-aa, ha-a, ha-a! Look at that! W-ha-a-a! Is that cool, or what? Ha-a, ha-a! Look at that! Wow! Look at that go! My goodness! Ha, ha, ha! It's bubbling all over! Ha, ha! Isn't that great?
