Convection - Oxford AQA IGCSE Physics

Front

What is convection?

Back

Convection is the main way that thermal energy is transferred through liquids and gases.

Front

In which states of matter does convection occur?

Back

Convection occurs in fluids, which are gases or liquids. It does not occur in solids.

Front

Why can't convection occur in solids?

Back

Convection requires the movement of particles, but in solids, particles are held in a fixed position.

Front

What causes convection currents?

Back

Convection currents are caused by changes in temperature leading to changes in density.

Front

Describe the process of convection when a liquid or gas is heated.

Back

When a liquid or gas is heated, the molecules more faster and spread apart, making it expand and less dense. The hot liquid or gas rises, and cooler liquid or gas moves in to take its place.

Front

What happens to a liquid or gas when it cools?

Back

When a liquid or gas cools, the molecules speed decreases and they move closer together, making the fluid more dense. The cold liquid or gas falls, and warmer liquid or gas moves into the space created.