Convection Currents
Physics: Edexcel IGCSE, topic 4.4.4
Convection
Liquids and gases are called fluids because they can flow. They do not conduct heat well, but they can transfer heat energy using convection currents. Convection currents are created by areas of different densities in a fluid. They work like this:
Stage 1
- When part of a fluid is heated, the particles in this area gain kinetic energy.
- When the particles gain kinetic energy they move away from each other, so the area that has been heated becomes less dense and the warm fluid particles rise.
Stage 2
- When the particles in the warm part of the fluid rise they transfer some of their energy particles to the cold fluid nearby.
- The heated particles then begin to sink because their density increases.
Stage 3
- At the bottom, colder fluid particles that haven't been heated will replace the warm particles that have risen.
- These colder particles are then heated. They move apart and start to rise.
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Stage 4
- This cycle creates convection currents. Convection currents are the result of different densities in the fluid. These different densities are created by heating.
Test yourself on Convection Currents
Which of the following are true of convection currents in a kettle?
What causes convection currents?
Convection Currents