Unit 3 Science Investigation Skills Topic E: Kinetic theory

Kinetic theory Kinetic comes from the Greek word kinesis meaning ‘movement’. Statement of kinetic theory: All matter is made up of particles that are continuously in motion. Matter is anything that has mass and takes up space (has volume).

Types of matter Solid Liquid Gas Plasma (ionised gas) Matter has four possible states:   Solid Liquid Gas Plasma (ionised gas) Matter can be changed from one state to another by giving the particles more energy by heating. The average energy of particles in a state of matter is a measure of the temperature of the matter.

Solids Solids have a fixed shape and cannot be compressed. This is because the particles in a solid: are close together are in a regular pattern vibrate about a fixed position. When heated, solids melt and form liquids.

Liquids Liquids flow, take up the shape of the container in which they are placed and cannot be easily compressed. This is because the molecules in a liquid: are close together are arranged randomly move around and change places with each other. When heated, liquids evaporate and form a gas.

Gases Gases completely fill any container in which they are placed and can easily be compressed. This is because the molecules in a gas: are far apart are arranged randomly move rapidly in any direction.   As temperature increases, the molecules move faster and gain more energy. If the temperature gets high enough the molecules will ionise to produce plasma.

Plasma Plasma will completely fill any container in which it is placed and unlike a gas will conduct electricity and is affected by electromagnetic fields. This is because the particles in a plasma: are electrons and ions are randomly arranged move very rapidly. Plasma is in the universe in the form of stars. On Earth we can see its effects in lightning, neon signs and plasma globes.