Teaching Guidance for 11-14
Air does the rising
Wrong Track: Switch the gas heater on. Then heat rises out of the top of it.
Right Lines: When the gas heater is switched on, the air above it is warmed up and rises.
Thinking about the teaching
The idea of
heat rising is very common in everyday speech and adds to the notion of heat being some kind of substance. In teaching about convection, it is therefore important to refer explicitly to the air being warmed up, reducing in density and rising through the colder surrounding air. That's why convection currents are a part of floating and sinking in the SPT: Forces topic.