States of matter
All Sub-atomic particles and anything made from them, such as atoms and molecules, are matter. Energy and forces are not matter. consists of particles including All elements are made of atoms. An atom consists of a nucleus containing protons and neutrons, surrounded by electrons. and A collection of two or more atoms held together by chemical bonds..
In everyday life, there are three states of matter - solids, liquids and gases.
The differences between the three states are due to the arrangement and spacing of the particles and their motion.
All matter contains particles.
The difference between the different states of matter is how these are arranged.
Solids
The particles in a solid:
- sit very closely together;
- are in a regular arrangement and in fixed position;
- vibrate about a fixed position but do not move through the solid;
- are held together by strong forces.
This explains why solids have a fixed shape and The volume of a three-dimensional shape is a measure of the amount of space or capacity it occupies, eg an average can of fizzy drink has a volume of 330 cm3..
Liquids
The particles in a liquid:
- sit close together but some gaps have appeared;
- can move past each other because of the gaps;
- have enough energy to prevent the forces between them holding them in a fixed, regular arrangement;
- are randomly arranged.
This explains why liquids have a fixed volume but take on the shape of their container.
Gases
The particles in a gas:
- are much further apart;
- are entirely free to move because the forces between them are weak;
- are randomly arranged;
- move quickly and randomly in all directions.
This explains why gases completely fill their container and have the same volume as their container.
Key facts
- solids have a fixed shape and volume;
- liquids have a fixed volume but take on the shape of their container;
- gases completely fill their container and have the volume of their container.