Convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it . Convection above a hot surface occurs because hot air expands, becomes less dense, and rises (see Ideal Gas Law).
What is the main cause of the convection method of heat transfer?
What causes fluids to rise and fall creating convection currents? Convection currents form because a heated fluid expands, becoming less dense . The less-dense heated fluid rises away from the heat source. As it rises, it pulls cooler fluid down to replace it.
How does heat transfer through convection examples?
radiator – A radiator puts warm air out at the top and draws in cooler air at the bottom. steaming cup of hot tea – The steam you see when drinking a cup of hot tea indicates that heat is being transferred into the air. ice melting – Ice melts because heat moves to the ice from the air.
What are 4 examples of convection?
- Breeze. The formation of sea and land breeze form the classic examples of convection. ...
- Boiling Water. Convection comes into play while boiling water. ...
- Blood Circulation in Warm-Blooded Mammals. ...
- Air-Conditioner. ...
- Radiator. ...
- Refrigerator. ...
- Hot Air Popper. ...
- Hot Air Balloon.
How does heat transfer occur in conduction?
Conduction is the process by which heat energy is transmitted through collisions between neighboring atoms or molecules . ... These vibrating molecules collide with their neighboring molecules, making them also vibrate faster. As these molecules collide, thermal energy is transferred via conduction to the rest of the pan.
What is an example of forced convection?
Forced convection: When external sources such as fans and pumps are used for creating induced convection, it is known as forced convection. Examples of forced convection are using water heaters or geysers for instant heating of water and using a fan on a hot summer day.
What are the two types of convection?
There are two types of convection: natural convection and forced convection .
Which is faster convection or radiation?
When a gas or a liquid is heated, hot areas of the material flow and mix with the cool areas. This type of heating is called convection. ... Convection transfers heat over a distance faster than conduction .
How is heat transferred through conduction convection and radiation?
While conduction is the transfer of heat energy by direct contact, convection is the movement of heat by actual motion of matter ; radiation is the transfer of energy with the help of electromagnetic waves.
Which of the following is the best example of convection?
- boiling water – When water boils, the heat passes from the burner into the pot, heating the water at the bottom.
- radiator – A radiator puts warm air out at the top and draws in cooler air at the bottom.
What is not an example of convection?
Non Example: The heat is transferred
What are the three main sources of convection?
The primary sources of thermal energy for mantle convection are three: (1) internal heating due to the decay of the radioactive isotopes of uranium, thorium, and potassium ; (2) the long-term secular cooling of the earth; and (3) heat from the core.
What is the purpose of forced convection?
Forced convection creates a more uniform and therefore comfortable temperature throughout the entire home . This reduces cold spots in the house, reducing the need to crank the thermostat to a higher temperature, or putting on sweaters.
What are the applications of forced convection?
Forced convection is typically used to increase the rate of heat exchange . Forced convection is often encountered for designing or analyzing pipe flow, flow over a plate, heat exchanger, Computer case cooling and so on.
What causes natural convection?
Natural convection arises from temperature differences among air parcels , or heat transfer at surfaces (i.e. surface-to-air temperature difference). In the absence of forced convection, natural convection becomes the only means of air mixing inside enclosed spaces.
What is the process of convection?
Convection, process by which heat is transferred by movement of a heated fluid such as air or water . ... Forced convection involves the transport of fluid by methods other than that resulting from variation of density with temperature. Movement of air by a fan or of water by a pump are examples of forced convection.
