How can a radiator quickly warm all the air in a rom when air is a poor heat conductor ?

[christy053]

How can a radiator quickly warm all the air in a rom when air is a poor heat conductor ?
christy_____;;<3

[SteveD]

Surely it's because the air near the radiator becomes warm, rises, and draws colder air towards the radiator. This colder air then warms up and rises etc etc. This moving air gradually disperses throughout the room.

[Clanad]

As an insert for Steve D's correct answer, you'll no doubtedly notice that most if not all of your radiators are placed under or at least near windows. This is to accentuate the mixing, as already discussed. In fact, during fairly cold weather, one can stand near the window above a radiator and feel the "draft" caused by the thermal interchange...

[Teddio]

The metal radiator heats the air touching it by conduction. The warm air is less dense than the cold air around it so the warm air rises by convection. One cubic metre of air has a mass of only 1.1kg so the heat capacity of the air in the room is very low. It takes very little heat emergy to heat up a roomful of air.

[mibn2cweus]

Air, especially when restricted in motion, due to its low density is a relatively poor conduit for heat transfer.

Heat is transferred by conduction (contact), convection (flow) and radiation (emission of light).

When air molecules come into contact with a heat source they are subjected to 'microscopic' molecular mechanical vibration and increase their energy and motion (conduction). This motion causes air molecules to separate further from each other decreasing group density and making it lighter. Lighter warm air is displaced by heavier colder air causing it to rise and be replaced by the cooler air (convection).

The heat energy released from a radiator as radiation of light passes easily through the low material density of air to solid objects such as walls and furnishings within the room. This radiant heat is what you feel placing your hand close to the radiator without actually touching it (contact).

Objects heated from radiation acting as secondary heat sources also contribute to the heating of the air. This case is observed in the heating of air by land masses heated by the radiation from the Sun.