Everything around us is made of matter.  Cars, rocks, people, and plants are all made of matter.  Matter makes up everything around us!

A solid does not change its shape.  Ice is a solid.  A rock is a solid.

A liquid flows.  Water is a liquid.  Water flows.  Flow means is can change shape.  Milk is a liquid.

A gas can change shape.  We cannot see most gases.  A gas can fill up a balloon, a tire, or a bubble.

Things can be a solid, a liquid, or a gas.  Water can be frozen as ice, liquid as drinkable water, or heated as steam.  This is called state of matter.  The state means if it is a solid, a liquid, or a gas.