Matter

Matter is everywhere! It makes up just about anything that you can think of. The only thing that isn’t made of matter is energy, which we will discuss later this year. What is matter? Well, matter has certain PROPERTIES that help you understand what it is. All matter takes up space. That means that all matter must have a VOLUME. Matter also has MASS. If it has mass and volume, it also has density (because density is mass divided by volume, remember?) Matter also has weight. The simplest definition of matter is anything that has a mass and a volume.

What kind of things have a mass and a volume you ask? I-pods, X-boxes, Ferbies and Mr. Potato-heads all have mass and take up space (volume). Scientist say that matter can be classified into four different “categories”. These categories are better known as States of Matter. The states of matter are Solids, Liquids, Gasses and Plasmas.

Solids

Solids are a state of matter. In order for matter to be a solid it must have certain properties.

A solid must have

· A definite shape.

· A definite volume.

· The particles that make up a solid are tightly packed and only vibrate.

What does that mean? Well, definite shape refers to the fact that a solid can hold its shape. If I put a solid into a container, its shape won’t change. For example, if I put a pine cone in a bucket, the pine cone’s shape will not change, therefore it has a definite shape. Volume is the amount of space something takes up. The volume of the pine cone does not change by putting it into a container either, so it has a definite volume.

The particles that make up a solid are trapped next to one another. They are packed so tightly that they cannot really move in any direction. You might think that they don’t move at all, but they do. They vibrate in place.

Liquids

Spit, blood, raindrops have mass and volume to, so they are also matter. They are liquids. What makes something a liquid? You might say, they are all wet, but some liquids aren’t wet (mercury for example.) In order to be a liquid, matter must have the following properties:

· No definite shape

· Definite volume

· Particles that are closely packed but free to move around a bit.

Liquids don’t have a definite shape because liquids can’t hold their shape. Mountain Dew in the can has the shape of the bottle. Pour the Mountain Dew into a graduated cylinder and it becomes the shape of the cylinder. Pour that into a rubber boot and you have a disgusting drink that is in the shape of a boot. The amount of Mountain Dew does not change however. If you start with one liter of soda in the bottle, you will have one liter of soda in the boot after you pour it in. The volume does not change so it still has a definite volume.

Swimming through liquids is hard work, but much easier than trying to walk through a solid! That’s because the particles that make up liquids aren’t packed as tightly as solids. The particles in liquids are packed somewhat closely but are free to move around each other. Think of a solid as an elevator stuffed with people. You can barely move at all. Someone else has to push the elevator button for you because you can’t squeeze by anyone to reach it. A liquid is more like a crowded cafeteria. It’s hard to move, but you can still make it to the salad bar with a little effort.

Gas

It’s hard to believe that a gas is matter because it’s invisible. Air is a gas. Does it have mass? Sure it does. Try lifting a car tire and you will see that air does have mass. What makes something a gas? In order to be a gas, the matter must have the following characteristics. A gas must have

· No definite shape

· No definite volume

· particles that are far apart and can easily move around

In class, I sprayed a small amount of cologne in the front of the class. Soon, the students in the back began to smell it. This is because some of the cologne became a gas and spread throughout the room. It took the shape of the room in a few minutes. This means that it does not have a definite shape. In addition, I only spritzed a little bit out of the bottle, but now it fills up an entire room. This means that the volume has changed too! A gas has no definite volume.

You know that it is easier to run in the air than it is to run underwater. That’s because the particles that make up a gas are very far apart. That’s why gases are invisible! Gas particles zoom around really fast and rarely hit each other.

Plasmas

Plasmas are the fourth state of matter. The particles that make up plasmas are moving very fast and are very far apart. You can see a plasma every time you look at a neon sign or see lightning. Plasma is a lot more abundant in outer space.

Phase changes

Water is a strange thing. It can exist on Earth as a solid, liquid or a gas under normal conditions. How does water change from a solid to a liquid to a gas? The answer is ENERGY! By adding energy or removing energy, you can make a phase change to something else. Heat is generally the energy that causes phase changes. Let’s look at an example.

Solid ice-Particles are packed close together and cannot move around past one another. They can only vibrate a little bit.

If we add heat to the ice, the ice cube will melt. Melting is how you change a solid to a liquid. When you melt ice, you add heat energy, the particles begin to move around more. They still stay close, but the particles can move around one another.

If you put the liquid into the freezer, the particles slow down again. They get closer and eventually lose the ability to move around. This is called freezing. Freezing is how to change a liquid to a solid.

Let’s say you put the melted ice cube into a pot instead of the freezer. If you turn on the stove, you will begin to heat up the water in the pot. The water molecules now begin to move around a lot more. The more heat energy you add, the faster they move. Eventually, some of the particles will have enough energy to escape from the other particles. When this happens, Vaporization occurs. Vaporization is also known as evaporation. Evaporation occurs when a liquid changes into a gas. When water is in a gas form, it is known as water vapor.

Water from mud-puddles evaporate on hot-sunny days. Where does it go? Straight up into the sky. As the water-vapor gets higher and higher, the air starts to cool down. This means less energy. The water vapor molecules start to get closer together. Eventually they get so close that they form tiny liquid water droplets. The water vapor (gas) is turning back into a liquid. This is called Condensation. Clouds are really just water vapor in the air that has condensed back into tiny water droplets. You also see condensation when you breathe onto a window in the winter. The water vapor in your hot breathe cools down when it hits the cold glass. The particles get close together and you wind up with liquid moisture on the window.

One strange phase change is sublimation. Sublimation occurs when a substance goes directly from a solid to a gas. The best example of this is dry ice. Why is it called dry ice? Dry ice is frozen carbon dioxide. This is the gas that’s in your breathe. Dry ice is like a solid ice cube, but it is much, much colder. Touching dry ice can actually flash freeze your skin. The weird thing is, if you take it out of the freezer, it will not melt into a liquid! Instead, you wind up getting a weird fog. The ice is turning into a gas!