What it is: Heat transfer in liquids and gases by the MOVEMENT of the fluid itself.
How a convection current works:
- Fluid is heated → particles gain kinetic energy → move faster → spread out
- Heated fluid becomes LESS DENSE
- Less dense fluid RISES (floats up)
- Cooler, denser fluid sinks to take its place
- This cooler fluid gets heated and rises
- Creates a continuous circulation = convection current
Key point: Convection CANNOT happen in solids (particles can't move position) or in a vacuum (no particles at all).
This key facts covers CONVECTION — Heat in Fluids within Heat Transfer for GCSE Physics. Revise Heat Transfer in Energy for GCSE Physics with 14 exam-style questions and 11 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 4 of 17 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Heat Transfer
Which method of thermal energy transfer occurs mainly in solids?
Explain how a convection current forms when the base of a fluid is heated.