Difference Between Conduction And Convection

Conduction and convection are two unlike forms of heat transfer. The major difference betwixt the two processes is the mode of transfer of oestrus. There is besides a third mode of transfer of heat which is radiation.

In conduction, the transfer of heat takes place through the direct contact betwixt the source of oestrus and the object to which rut is transferred while in convection there is no direct contact.

Before diving deep into the difference between conduction and convection , let's find out what heat is and how the transfer of rut takes place.

Heat is basically a class of energy that flows from a body at college temperature to a body at lower temperature, or we tin can say that it flows from a body having college kinetic energy to a trunk having lower Kinetic Free energy.

Conduction vs Convection

Now, permit's briefly differentiate between the two through a tabular array.

Footing of Comparison	Conduction	Convection
Mode of Oestrus transfer.	For conduction to occur there should be direct contact between the bodies.	Direct contact betwixt the bodies is not required.
Observed in	This form of estrus transfer is by and large observed in solids.	This form of heat transfer is observed in fluids and gases.
Cause of occurrence	Transfer of heat takes place due to differences in temperature.	Transfer of heat takes place due to the departure in densities between the two bodies.
Rate of occurrence of the process	This process is quite slow.	Heat transfer through this procedure takes place at a faster rate.
Arises from	Molecules at residue or free electrons.	Molecules in motility.
How information technology takes place	It takes place due to molecular collision.	It takes place due to the diffusion of heated particles.

What is Conduction?

Conduction is that fashion of transfer of oestrus free energy that requires straight contact between the ii bodies to transfer heat. If we observe at the microscopic level, there occurs a collision betwixt the molecules to transfer the Kinetic energy. It is the almost common form of transfer of heat.

The molecules with higher kinetic energy collide with the molecules of lower kinetic free energy and transfer of energy takes identify, in this style the particles with lower kinetic free energy acquire more than energy. This process continues and free energy gets transmitted till the temperature of the two bodies becomes the same.

The process of conduction depends on the following factors: cross-section of the textile, physical material properties, temperature gradient, and length of the travel path. The larger the exposed surface area, the more heat is lost. If the length or size of the object to be heated is more, more than amount of heat is required to heat it. The Heat will flow from a body at a higher temperature to a trunk at a lower temperature.

Physical properties also affect the charge per unit of heat menstruum through conduction, the material with a college coefficient of thermal electrical conductivity will accept a higher rate of conduction and vice versa.

The rate of oestrus transfer in conduction is given past the equation:

$Q=k\: A \: \frac{T_{hot}-T_{cold}}{d}$

Where Q = amount of oestrus transferred per second,

A = expanse in contact, k is the thermal electrical conductivity of the material, d is the thickness of the material, T_hot and T_cold are the temperatures of the hotter region and colder region respectively.

What is Convection?

It is another eminent mode of transfer of rut energy. In this way of heat transfer, there is the displacement of fluid molecules from one region to the other. The nigh common case of convection which can oftentimes be seen in our homes is when nosotros heat water, small bubbles of water can exist seen ascent from the bottom of the container. The hotter water expands and its density decreases then it rises to the meridian and provides energy to other water molecules while the colder water sinks to the bottom, this procedure keeps repeating.

The equation for the rate of heat menses by the procedure of convection is as follows:

Q = h_c · A · (T_southward – T_f)

Where Q= rut transferred per unit fourth dimension, A = area of heat transfer, h_c is the convective rut transfer coefficient, T_f is the temperature of the fluid and T_{due south} is the temperature of the surface.

Gravity does not play whatever role in conduction and radiations considering there is no actual motion of particles in these two processes but there is the movement of particles of medium in convection so hither gravity plays an of import role. The rate of oestrus flow in convection is faster than conduction merely slower than radiations.

Conclusion

Conduction can take identify in solids, liquids, and gases but it is maximum in solids considering the molecules are closely packed in case of solids. Convection is observed in fluids and gases. Conduction takes place due to differences in temperature while convection occurs due to differences in the densities of the objects. Nosotros have explained the differences betwixt conduction and convection in great detail.

Writer
Deepak Yadav
Aligarh Muslim University, Aligarh

References

1. https://www.machinedesign.com/learning-resources/whats-the-difference-betwixt/document/21834474/whats-the-difference-between-conduction-convection-and-radiation
ii. https://circuitglobe.com/divergence-between-conduction-and-convection.html