Have you ever wondered how solids, liquids, and gases are different? In this lesson, find out what makes them have different properties and what this has to do with the particles that they're made from.
What's the Matter?
Look around you. Everything you see on Earth is made of matter. Scientists use the word 'matter' for anything that takes up space and has mass. Atoms and molecules, the building blocks that make up everything, are made of matter. But, not all matter is the same.
There are three different states of matter on Earth because matter can change! An ice cube is in the state of matter that we call a solid. If you left it on the counter, it would melt into a puddle of water. Now it's in the state of matter called a liquid. If you don't clean up the water, it will eventually evaporate and disappear. When this happens, it's in the state of matter called a gas.
Let's learn more about each one of these states of matter.
Simple particle theory says that all matter is made up of extremely tiny particles - such as atoms or molecules - that are always moving. Let's see how these particles change from one state of matter to another.
When there isn't much space between the particles in matter, they're packed together very tightly. They can't move around very much, but they do move a little bit. They're very attracted to each other, so they stick close together. This is the state of matter we call a solid. The particles in a solid are arranged in a pattern.
Imagine that we put 100 people in your bedroom. They'd all be so close together that there wouldn't be room to move much, but they could still move without moving their feet. They might be able to shake hands, for example, even if they couldn't walk around. That's how particles in a solid move. They vibrate, or shake, in place, and they move slowly.
Solids have a definite shape that doesn't change. If you had a solid, such as a book, and you put it on the kitchen table and then moved it to your backpack, it would stay the same shape in both places.
The particles in a liquid are further apart than the particles in a solid, but they're still fairly close together. Because they aren't so tightly packed together, they can move around more. They're still attracted to each other, like the particles in a solid, so they don't get very far apart, but they can move around more. They move faster than the particles in a solid, but not as fast as the particles in a gas. The particles in a liquid aren't arranged in a pattern.
Also, unlike solids, liquids don't have their own shape: they take the shape of the container they're in. If you put water in a tall bottle, the liquid (the water) takes the tall shape of the bottle. If you pour it from the tall bottle into a round bowl, the liquid takes that shape. A liquid will take the shape of any container you put it into.
The particles in a gas aren't tightly packed together at all. There's lots of room for them to move around very quickly in all directions. Sometimes, they even bump into each other as they move. The particles in a gas aren't very attracted to each other and aren't arranged in a pattern.
Just like liquids, gases don't have their own shape and will take the shape of the container they're put into. Since there are only a few particles, they can be pressed together to take up less space.
Let's review. Simple particle theory tells us that all things on Earth are made of particles and are in one of the three states of matter: solids, liquids, or gases. Particles in each state of matter move differently and give the matter different properties. Solids have their own shape, but liquids and gases take the shape of the container they're in.