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.
🔄 CONVECTION — Heat in Fluids
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).
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.