Watch dust drift above a radiator and you are seeing air on the move. Heated air swells, grows lighter than its surroundings and floats upward, while cooler, denser air slides down to take its place, around and around.
Convection is the transfer of thermal energy through a fluid by the movement of the fluid itself. Heated fluid expands, becomes less dense and rises, while cooler, denser fluid sinks, setting up a convection current.
Convection is the transfer of thermal energy through a fluid (a liquid or gas) by the movement of the fluid, caused by density differences when it is heated.
It happens only in fluids, never in solids, because the particles must be free to move.
Heat a fluid from below and watch the warm fluid rise and the cool fluid sink into a circulating current.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
Convection occurs in...
When part of a fluid is heated it...
A convection current forms because warm fluid rises and...
Convection cannot occur in...
Every part of a convection current comes back to one cause: differences in density.
Heat does not simply rise on its own. The heated fluid expands and becomes less dense, and it is pushed upward by the denser, cooler fluid sinking around it. The cause is the difference in density.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
A radiator warms a whole room mainly by...
Warm air rises above a heater because it is...
Convection does not happen in a solid because its particles...
Two heat-transfer skills down. Keep the chain going.