warm air rises because of convection.
A student holds the back of his hand near an iron to see if it's hot. The heat transfer is conduction.
Warm water moves throughout a mattress because of ... why is there warm water in a mattress again? Convection, I guess.
In a swimming pool, the water near the surface is warmer because of convection and solar radiation; it's closer to the Sun than the bottom of the pool, so it receives more thermal radiation, making it warmer.
