From stars to dust, plants to animals, all things in our world and universe are made up of matter. Some forces move matter, such as heat and sound. Some forms of energy are closely related to matter, yet are usually not considered matter, such as light, radio waves, and X-rays. Matter has mass. This is the amount of matter, or material, that shows resistance to being moved.
Some matter has little mass, like a small toy car that moves easily with a soft touch.
Some matter has a large mass, such as a bulldozer which could not move with the push of a strong man. Matter may be in a liquid state, solid, or gas state. Matter that keeps a constant state and has a constant volume is a solid. Glass, cars, fences, and appliances are examples of solid matter. Most solid matter will become liquid when enough heat is applied.