There are som certain properties of matter, like what it looks like, what it feels like, what it smells like, what it sounds like, and what it does (e.g bounce, flow, spin ect.).
Matter also has three states; Solids, Liquids, and Gases.
The particles, atoms or molecules in solids are very close together and do not move around very much. Solids have a definite shape and volume, which does not change.
The particles in liquid aren't very close to each other, and are free to move around. Liquid cannot take shape by itself, you need to put it in something to prevent it from flowing away.
The particles in gas are not linked together at all. They shoot out everywhere and fill all the space they are in. Gas has no definite shape or volume.
One example that contains all three states is simple water. At room tempreture it is water, at below 0 °C It freezes into ice, a solid, and when you boil water it turns into water vapour, a gas.
There are two types of changes in matter. One is physical change, and the other is chemical change. Physical change is change in apperance, such as cut, tear, freeze ect. Chemical change is when a new matter is formed, such as burn, cook, rust ect.
Matter is anything and everything