Question

which of these is an example of convection? you burn your feet on the hot sidewalk. you sit near a campfire and feel warm. a floor heating vent sends warm air throughout a room.

Explanation:

Convection is the transfer of heat by the movement of a fluid (liquid or gas). In the case of a floor - heating vent sending warm air throughout a room, warm air (a gas) is in motion, carrying heat. Burning feet on a hot sidewalk is conduction (heat transfer through direct contact). Feeling warm near a campfire is radiation (heat transfer through electromagnetic waves).

Answer:

A floor heating vent sends warm air throughout a room.