States of Matter

The Atoms' Cousins


There exist four States of Matter and these are Solids, Liquids, Gases and Plasma. You can identify all of these States of Matter very well because of their unique characteristics. All four States of Matter are observable in your everyday life.

Solids, Liquids and Gases

The Solids' Characteristics

The Solids have a fixed shape, which means that when they are created they will remain as they are. The Solids also have a fixed volume; they cannot change their size. Solids have a very high density, which shows that they are very compact. Solids cannot flow and are very hard to compress. In a Solid, the particles are very close together and vibrate a little bit. This shows how dense the Solid is.

The Liquids' Characteristics

Liquids have no fixed shape, they will spread out if you pour some. Liquids will always take the shape of their container. However, like Solids, they have a fixed volume. The Liquids are usually less dense than Solids because their particles are close together but they can move past each other. Liquids can flow very easily but are quite hard to compress.

The Gases' Characteristics

Like Liquids, Gases have no fixed shape. They will spread out all over the container. If it is not sealed, the Gas will escape and this is called diffusion. Gases have no fixed volume and they have a very low density; their particles are spread out and free. They can flow easily and can be compressed.

The Characteristics Table

Particle Theory

In the States of Matter, the particles always stay he same, although the arrangement and energy can change. It explains the characteristics of a solid, Liquid or Gas.


Solids have very strong bonds, which keep it in a fixed position and regular arrangement. The particles can also vibrate. Solids keep a definite shape and volume because the particles do not move from their positions. Solids cannot be crompressed easily becuase the particles are very close together. They are dense becuase there are many particles in a small volume.


There are less forces of attraction between liquid bonds than in Solids so the particles are close but free to move past each other and stick together. Liquids never keep a definite shape, They flow and take the shape of a container. They keep the same volume. The can be compressed quite easily becuase the are compact. They are quite dense becuase there are many particles in a small volume.


Gases have very weak forces of attraction between the particles. The particles are very far apart and can move freely in all directions. The particles move quickly and smash against each other and their container. They do not keep a definite shape or volume and expand to take all the space in a container. They can be compressed easily becuase of the free space between the particles. Gases have very low densities becuase there are few particles in a big volume.



When you add heat to Solids, Liquids and Gases, the particles will vibrate more, making you think the object is expanding. When you take heat away, the particles compact, making you think that the object is getting smaller. However, there is one exception, when you freeze water it will expand.

These are the transitions between each State of Matter

When Solid particles are heated, they gain more energy and the bonds keeping the Solid together weaken. This is makes the Solid expand. At a certain temperature, the bonds break and the Solid turns into a Liquid. This is called Melting. When the Liquid is heated, the particles get even more energy. The particles move faster and this weakens the bonds and breaks them. Then the Liquid can turn into a Gas. This is called Boiling.

Gas Pressure

When Gas particles are heated, they gain more energy. This will make them move quicker, which has two effects: they hit the walls harder and more often, this causes pressure. If you compress the particles, this also creates more pressure because the particles are in a smaller volume, which means they will hit the walls more.


Diffusion is the spreading out of particles so there is the same concentration everywhere. The process of diffusion is always very slow. Smelll particles move to where there are not so many. It is slow becuase the smell particles bump into the air particles, which stops them going forward and sends them to another direction.

Sand Experiment

Is sand a Solid or a Liquid? It is true that sand can flow although does it take the shape of its container perfectly? I will leave the end for you guys to find out.
The Matter Song (Solid or a Liquid or a Gas)