A solid is matter that has definite size and shape.
A liquid is matters that takes the shape of any container.
Gas is matter that has no definite shape. Gases take on the shape of whatever container they are in.
States of water
Water is a great example of the three states of matter. At room temperature, it is a liquid. When it’s frozen it becomes a solid in the form of ice. When it’s heated to boiling point it turns to gas in the form of steam.
List some every day objects. Identify if they are a solid, liquid or gas.
Freezing: Changing Liquid Into Solid
Lava is liquid rock, which erupts through a volcano at temperatures as high as 1,500ºC (2,732ºF) through a volcano. However, the red-hot lava cools as it meets the Earth’s surface, and turns back into solid rock again. This change from liquid to solid is called freezing or solidifying. It is the opposite process to melting.
When you place water in the freezer, it becomes a solid. This process is called freezing.
Melting: Changing Solid Into Liquid
When a solid is heated, the particles are given more energy and start to vibrate faster. At a certain temperature, the particles vibrate so much that their ordered structure breaks down. At this point the solid melts into liquid. The temperature at which this change from solid to liquid happens is called the melting point. Each solid has a set melting point at normal air pressure. At lower air pressure, such as up a mountain, the melting point lowers.
Boiling: Changing Liquid Into Gas
When a liquid is heated, the particles are given more energy. They start to move faster and further apart. At a certain temperature, the particles break free of one another and the liquid turns to gas. This is the boiling point. The boiling point of a substance is always the same; it does not vary.