Because of the excellent conductivity of iron, very damaging amounts of heat would transfer to your feet. Open ended, that likely incorporates the physics of the previous three exercises. Agree, for your friend is correct. The motion of molecules in a gas is random and haphazard. Collisions abound in every possible direction-some head on, some glancing.
Some molecules speed up, some slow down.
In the absence of heat input or heat output, what remains the same is the average kinetic energy of the gas. Hence in a gas of given temperature, there are molecules below and above the average kinetic energy. Heat the gas and its molecules move faster and produce greater pressure within the can. Cool the gas and molecules slow down and exert less pressure. The smoke, like hot air, is less dense than the surroundings and is buoyed upward.