Matter is everything around you. Matter is made up
of atoms and molecules. It is anything that has mass. There are three
basic kinds or states of matter: solid, liquid, and gas. Each of these
states is also known as a phase. Elements and compounds can move from
one phase to another and remain the same compound. You can see water
vapor over a boiling pot of water. That vapor, or gas, can condense and
become a drop of water. If you put that drop in the freezer, it would
become a solid. No matter what phase it is in, it is always water.
Solids are usually hard because their molecules
have been packed together. The closer the molecules are, the harder the
solid is. Solids can also hold their own shape. A rock will always look
like a rock unless something happens to it. The atoms inside a solid are
not able to move much. Think of a box packed full of marbles, this is a
representation of the atoms of a solid. The atoms cannot move much
inside the box. This is one of the physical characteristics of solids.
Atoms and molecules in liquids and gases are able to bounce and move
around, free to go where they want. The molecules in a solid are stuck.
The atoms can spin, but not change position.
The second state of matter is a liquid. Solids are
hard things that you can hold. Gases are floating around you. Liquids
are the “in-between” state of matter. Liquid molecules are not as close
together as molecules in a solid, and move around more freely. Liquids
have no regular shape or arrangement and move freely. One characteristic
of a liquid is that it will take the shape of a container. You can fill
a glass with water, and the water takes the shape of the glass. You can
pour that water into a mug, and it will take the shape of the mug.
The last basic state of matter is a gas. Gases are
hard to identify because they have no color or shape. The molecules in a
gas move freely at high speeds. There is a lot of space in between the
molecules, and they can take the shape of any container. Gases are all
around you. Take a deep breath and feel your lungs get bigger. Your
lungs are filling up with air, and air is a combination of many gases.
These phases can be seen everywhere around you.
Sometimes the phases can even change right before your eyes, like when
ice melts in your water.