Any matter made up of atoms and molecules has the ability to transfer heat. The atoms are in various states of motion at any time. The motion of atoms and molecules is responsible for heat or thermal energy and every matter has thermal energy. The more the molecules move, the more will be heat energy. Thus, the difference in temperature is considered to be a ‘potential’ that causes the transfer of heat from one point to another. 

Heat can travel from one place to another in different ways. And, if the two systems have different temperatures, heat will find a way to transfer from the higher to the lower system. The different modes of heat transfer include conduction, convection and radiation. Check out the article to learn more about heat transfer and its three distinct ways of transfer.

What is Heat Transfer?

According to thermodynamic systems, heat transfer is “The movement of heat across the border of the system due to a difference in temperature between the system and its surroundings.”

Heat is a curious form of energy. Heat transfer is a phenomenon that occurs when one object transfers heat to another. Generally, this happens from the object that is hot to the cold object. Even nuclear energy generates electricity by utilising the heat produced by the atom. Heat transfer can occur through three means, it includes:

• Conduction
• Convection
• Radiation

Conduction

Conduction is “The process of transmission of energy from one particle of the medium to another with the particles being in direct contact with each other”.

Conduction is also known as heat conduction or thermal conduction. A higher kinetic energy area transfers thermal energy to a lower kinetic energy area. When high-speed particles collide with slow-moving particles, the slow-moving particles gain kinetic energy. This is a common type of heat transfer that occurs through physical contact. 

The transfer of heat by conduction occurs at a molecular level. Absorption of heat by a body causes the molecules of that body to gain energy. In the process of gaining energy and vibrating excessively, they bump into their neighbours and transfer a little of their extra energy to them. The extra energy appears in the neighbouring molecules and heats them up too. That is how heat is transferred as long as heat is being supplied.

Examples of Conduction 

Following are some of the examples of conduction:

• Heat is transferred from hands to ice cubes resulting in the melting of an ice cube when held in hands.
• Ironing of clothes is an example of conduction since heat is transferred from the iron to the clothes.
• Light bulbs emit heat.
• Sand is a good conductor of heat. Because of this, walking on the beach on a hot summer day will warm your feet.

Factors affecting Thermal Conductivity

The rate of thermal conductivity depends on the following factors:

• A temperature gradient is a physical quantity that illustrates in which direction and at what rate the temperature changes the most rapidly. This tells us about the temperature difference between places and the direction of the transfer due to it.
• Cross-section and path length is dependent on the physical dimensions of the body. When the size of the body is large, the heat required to heat it is also larger. When dealing with large bodies, we must also consider heat loss to the environment. Additionally, a greater surface area between the hot and the cold body implies a greater rate of heat transfer.
• The physical properties of the body play an immense role in the thermal conductivity of the body. 

Convection

Convection refers to the method of heat transfer that occurs usually in the liquid and gaseous states. According to this method, the transfer of heat energy takes place when there is an actual motion of the matter from one place in the body to another. 

Examples of convection may include:

• When boiling the water, the denser molecules move at the bottom. Whereas the molecules that are less dense move upwards, resulting in the circular motion of the molecules so that water gets heated.
• Warm water around the equator moves towards the poles, and cooler water at the poles moves towards the equator.

Radiation

Radiation is a process of heat transfer which does not need any sort of medium and can easily be used for the transfer of heat in a vacuum. The process of heat transfer via radiation makes use of electromagnetic waves that tend to transfer the heat from one place to another. 

Following are some examples of radiation:

• Sunlight is a great example of the radiation process. Both light and heat from the sun reach the Earth through the process of radiation. 
• Microwave radiation emitted in the oven is also an example of radiation.

We hope this article on Heat Transfer Thermal Conduction has helped you. Stay tuned to embibe.com for more informative articles.