The material that makes up the universe is known as matter. Matter is defined as any substance that occupies space and has weight. Gases not only take the shape of the containing vessel, but also expand and fill the vessel, regardless of its volume. Examples of the states of matter are iron, water, and air. Matter can change from one state to another.
Water is a good example.
At high temperatures it is in the gaseous state known as steam. At moderate temperatures it is a liquid, and at low temperatures it becomes ice, which is definitely a solid state. In this example, the temperature is the dominant factor in determining the state the substance assumes. Pressure is another important factor that will affect changes in the state of matter. Pressure is also a critical factor in changing some gases to liquids or solids.