What are the States of Matter? | Biology Review
States of Matter
The three classical states of matter are solids, liquids, and gases. First, we’re to look at solids and we’re going to look at some of the characteristics of a solid. Solids have a definite volume and density.
We would say they have a definite volume and density at a given temperature and pressure. This white board, for example, is a solid. The volume of this white board isn’t changing, and the density of this white board isn’t changing.
The second point of a solid is that it has a degree of structural rigidity and a constant shape. Notice that this white board has structural rigidity and a constant shape. The shape isn’t changing. It also has a resistance to flow.
Now, some solids, such as modeling clay, can flow and undergo deformation under pressure. I’m just going write here that there are exceptions, but, for the most part, solids have a resistance to flow. Now, the second state of matter is the liquid. Like solids, at a particular temperature and pressure it has a definite volume and density. The reason I say “at a certain temperature and pressure” is because at a different temperature and a different pressure, this white board may have a little bit of a different volume and a little bit of a different density. As long as it stays at the same temperature and pressure, then it’s going to stay the same. The volume and diversity are going to stay the same. The same thing with the liquid. Now, a liquid does not flow readily, so that makes it a lot different than a solid.
It does not expand to fill the container. It’s going to flow readily if you’ve spilled water on the ground. It wouldn’t all just stack up in one spot. It would flow all over the place. If you were to pour water into a glass, the water is going to expand fill up that whole glass.
It’s going to keep the same volume. Now, that’s different than the third state of matter, which is gas, because the main thing about a gas is that it will expand to fill a container. If a gas was exposed in this room, it wouldn’t all stay in one spot. It would eventually move to fill the entire room.
Now, the molecules are spread much farther apart, and they move more rapidly and randomly than in a liquid. Basically, the molecules move the slowest in the solid, they move a little faster in a liquid, and then they move the fastest in a gas.
That’s why gases are spread apart, because they’re moving around so much and bumping into each other and pushing away from each other. A liquid has more moveability to it, I guess (if that’s a word). It can move more because the molecules move more.
Then, a solid, if you think about ice, it’s not really doing anything. It’s just sitting there, because it’s a solid. The molecules are moving and really slowly. Gas is far more dispersed than even a liquid, because it’ll expand to fill an entire container. And so that’s a look at the three states of matter.