Duduli

Convection is the process in which heat is transmitted from one place to the other by the actual movement of the heated particles.It is prominent in the case of liquids and gases.Land & sea breezes and trade winds  are formed due to convection.Convection plays an important part in ventilation, gas filled electric lamps and heating of buildings by hot water circulation.

Rooms are provided with ventilators near the ceiling.Air in the room gets warmer due to respiration of people in the room.Warm air containing more of CO2 & water vapour has less density and moves upwards.Fresh air from outside enters the room through the doors & windows.The impure air moves outside through the ventilators.The phenomenon is continuous.