Question

In a room it is best to place a room heater on the floor , but an air conditioner near the ceiling. Explain.

Answer 1

Because warm air being lighter rises up while the cold air being densser come down

Answer 2

Hello Dear,
sorry i can only answer the heater part.Here you go:
''A  room heater is kept on the floor because it causes warm air and rises it up.the cool air sinks down,get warmer and rises up.in the result the whole area is now filled with warm air.Thankyou :)