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Convection - GCSE Physics Definition

Reviewed by: Leander Oates

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What is convection?

In GCSE Physics, convection is a mode of energy transfer that occurs in fluids (liquids and gases). A convection current is formed when the warmer, less dense parts of a fluid rise while the cooler, denser parts sink, creating a circulation pattern.

Diagram showing convection currents in a liquid with heat applied below. Red arrows indicate upward movement of the warmer liquid, blue arrows show downward flow of the cooler liquid.
Convection current demonstrated using potassium permanganate in water

This process transfers thermal energy throughout the fluid, leading to an even distribution of temperature. Convection is responsible for various natural phenomena, such as the movement of air when heating a room, the circulation of air in Earth's atmosphere and ocean currents.

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Leander Oates

Reviewer: Leander Oates

Expertise: Senior Physics Content Creator

Leander graduated with First-class honours in Science and Education from Sheffield Hallam University. She won the prestigious Lord Robert Winston Solomon Lipson Prize in recognition of her dedication to science and teaching excellence. After teaching and tutoring both science and maths students, Leander now brings this passion for helping young people reach their potential to her work at SME.

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