Conduction, Convection and Radiation
Conduction
Conduction is the method of transferring heat within a body or from one body to another caused by the heat transfer by molecules vibrating at their mean positions. The bodies involved in the heat transfer must be in contact with one another. When heat is transferred from one location to another, there is no actual movement of matter.
Conduction is most frequent in solids, where molecules are kept together by intermolecular forces of attraction, causing them to only vibrate about their mean locations as they receive heat energy and hence pass it on to the surrounding molecules via vibrations.
Convection
Convection is a heat transport method that occurs mostly in liquids and gases. Heat transfer occurs in this mechanism when the substance is moved from one location within the body to another. Eg. It is often witnessed bubbles and currents arise in boiling water. (Fig 1)
This is an excellent illustration of the convection process. The hot water at the bottom gets lighter and rises, causing the colder, denser water at the top to descend and heat up.
Radiation
Another method of heat transport is radiation. It works without the use of a medium and can even transfer heat in a vacuum. Electromagnetic waves are used in this way to transfer heat from one location to another. Radiation is how the sun's heat and light reach our planet in our solar system.
Radiation is, in fact, the most powerful means of heat transport. We feel warm without touching the burning wood when we sit near a fire in the winter. Only radiation makes this possible.
Differences
FAQs on Difference Between Conduction, Convection and Radiation
1. How many different types of heat convection are there?
It’s a process of transferring heat in a fluid by the fluid itself moving. Heat convection can be broken down into two types.
Natural or Free Convection: When the fluid's motion is simply owing to the presence of a hot body in it, causing temperature and density gradients, the fluid moves under gravity's influence.
Forced Convection: In this sort of convection, an external agency maintains a relative motion between the heated body and the fluid.
2. State a few examples of Conduction of Heat Transfer.
Below are a few examples of Conduction of Heat Transfer:
Utensils that are used to handle charcoal or other things that are very hot. People should keep in mind that there is a lot of space between the pipes, so the heat transfer is going to be slower.
Everything melts when you put hot water and ice in a cup.
Gas stoves heat the pot when you start to boil water. In a second, the water is ready.
3. In terms of heat conductivity, how do metals vary from non-metals?
Free electrons exist in metals. Within the metal objects, these free electrons travel at extremely high speeds. As they move, they carry energy from heat to cold sections of the item at a very fast rate.
As a result, heat from the hard sections of metal things reaches the cold parts of metal objects considerably faster than heat from nonmetals.
All metals are excellent heat conductors. Bad conductors or insulators are substances that do not allow heat to easily pass through them.
Wood, cork, cotton, wool, glass, rubber, and other natural materials are poor conductors or insulators.
4. What are the examples of Convection?
A water pump in a residence that divides hot water for effective distribution, passing through a mechanism (the pump) so that it may be distributed to the shower and the person can bathe with the appropriate amount.
When cooking cold food in a home oven, convection technology is used so that the user may control the temperature. A stream of hot air will circulate internally.
Convection happens at the ocean's bottom, when the energy of the water meets the chilly top, resulting in ocean currents.
5. Why does a hot cup of tea get chilly after a while?
All of the objects in a room, including the walls, roof, and floor, emit heat. They do, however, absorb heat at the same time. When an object's temperature is higher than its surroundings, it radiates more heat than it absorbs.
As a result, its temperature continues to fall until it reaches the temperature of its surroundings. At this point, the body is spending the same amount of heat that it is absorbing.
When an object's temperature is lower than its surroundings, it radiates less heat than it absorbs. As a result, its temperature rises until it reaches the temperature of its surroundings.