F.3 physics-走馬燈同對流有咩關係?

A revolving lantern(走馬燈) is just a simple form of gas turbine(氣體渦輪機).
The light source (generally a light bulb or a candle) inside the lantern heats up the surrounding air. The hot air, because of its lower density, rises and is made to pass through a pinwheel (風車) at the top. The pinwheel is then pushed by the hot air to revolve and hence brings a paper cylinder hung from it to revolve. This is the principle of a revolving lantern.
Therefore, a revolving lantern in fact works on the convection current set up by the hot light source.