States of Matter

Everything is made up of tiny particles. The state of a material depends on how strong the forces of attraction are between the particles of the material.

When looking at objects around us, we can see that different objects are in different states of matter. The Particle Theory Model is used to explain the unique properties of the different states of matter.

The three states of matter are solidsliquids and gases. Let’s look at how particles are arranged in each state of matter, as well as their properties.


This diagram represents solids. As shown, the particles are very close together causing them to be arranged in a regular lattice shape. The particles are close together due to the strong forces between them.

Solids keep a fixed shape, meaning the particles are unable to move around.

The particles are able to vibrate during certain conditions. For example, when heated, the particles begin to vibrate around a fixed position.


  • Ice cubes are in a solid state


Liquid particles are arranged in random positions. This is because the forces between them are weak. Having said this, some of the particles are still close together.

Liquids take the shape of containers, as they are able to flow.

The liquid particles are always randomly moving. Similar to solids, when heated, the particles vibrate more.


  • Water is in a liquid state


Gas particles have very weak forces between them, so they are able to move around freely. As you can see in the diagram above, the particles are very far apart from each other. Gases can always take the shape of containers because they have no definite shape.

When you increase the level of heat, gas particles move faster.


  • Water vapour is in a gaseous state

Comparing the States of Matter

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Below is a table which compares the three states of matter.

Arrangement of particlesRegular arrangementRandom arrangementRandom arrangement
Movement of particlesVibrate around a fixed positionMove around each otherMoves quickly in all directions
Closeness of particlesVery close togetherClose together with no regular arrangementVery spaced out