Difference between conduction and convection physics
|Material medium is an essential||Material medium is also essential|
|Transfer of heat can be in any direction||Heat is transmitted vertically upward|
|Transfer of heat takes place at slow rate||This process is slower than radiation and faster than conduction|
|Molecules do not leave their mean positions||Molecules to move from one place to another place|
Conduction: Read about it Here
==> Convection is the transfer of heat by the motion of material. The hot-air furnace, The hot water heating system and flow in the blood in the body are some examples.
It is the process in which heat is transferred through a substance from one point to another with the actual motion of heated particles.
Such a process takes place in liquid and gas. When water is heated in a beaker, first of all, water molecules at the bottom becomes hot and risen up. The cold water having higher density moves down. In this way a chain of rising and fall of water molecules takes place. As a result, all the molecules become hot and water boils. Land and sea breezes, winds in the atmosphere are formed due to convection. Convection plays an important role in ventilation, heating and cooling system in houses.
It is observed that the rate of transfer of heat is directly proportional to the temperature difference between two parts of the convective fluid and to the surface of the fluid exposed. So
Application of convection
i)Ventilation: The room are provided with ventilators near the ceiling. Warmer air in the room due to respiration of people in the room has less density and moves upwards. To fill the space of this air, fresh and cold air from outside enters the room through the doors and windows. So, the warm air moves outside through the ventilators continuously keeping the room cool.
ii)Tradewinds: When the earth’s surface near the equator gets heated by the sun, the air in contact with the earth’s surface gets heated and risen up. The cold air from the poles moves towards the equator where the pressure is low. Therefore, the convection current of air starts between the equator and the poles. Due to the rotation of the earth from west to east, the convection current drifts towards the east, therefore the steady wind i.e convection current of air blows from northeast towards the equator, which is called trade wind.
Also read: Application of conduction- Physics
Other chapters of physics Read it here
- Kinetic Theory of gases postulates physics grade 11
- Experiment Veriner calliper Grade 11 physics
- Important question physics unit gases and gas law grade 11