What is Convection

Convection is a type of heat transfer. Thus before understanding what is Convection? It becomes essential to first understand what heat transfer is? Heat transfer is defined as the movement of heat from one body to another due to the difference in temperature. Different processes carry out the transport of heat from one body. In every phenomenon of heat transfer, the momentum, mass and energy are either gained or lost from a system.

In this article, we will provide you with a brief understanding of the different heat transfer phenomena. Besides explaining the different ways of heat transfer, we will also explain the two types of Convection.

Convection

What is Convection? Convection is defined as the type of heat transfer in which the movement of matter transfers the heat. Convection is a heat transfer process that can only occur in fluids. 

Convection is primarily of two types

• Natural Convection

Gravity plays an essential role in natural convection. When we heat a fluid, the hot region in the fluid expands. Thus its density decreases. The decrease in the density of the fluid makes the fluid buoyant. Thus, the hot fluid starts to rise and replace the cold fluid. Once hot fluid replaces the cold fluid, the replaced cold fluid gets heated up, replacing the other cold fluid layer. This Process of heating of layers and replacement of layers keeps going on. During convection, the bulk transport of fluid takes place.

• Forced Convection

In the case of forced convection, the cooling or heating material is pumped into the system with the help of some external source. Some of the common applications of forced Convection are domestic heating systems, human blood circulation systems and air conditioning systems of a car. The human heart acts as an external source responsible for pumping blood into the human body. Convection importance is extremely vital in the case of human life. Because if Convection wasn’t there, then humans wouldn’t be able to survive. 

Development of Sea Breeze due to Natural Convection

What is Convection? It is an essential question to answer before knowing the application of natural Convection in the development of sea breeze on land near the oceans.

Natural Convection plays an important part in striking a balance between rainfall and summer. During the daytime, the land heats up faster in comparison to the water bodies. This phenomenon occurs primarily because water possesses a greater specific heat and the air currents present above the water spread the heat throughout the water bodies. Thus, heating the water bodies unevenly. 

However, in the case of land, the surface is heated due to conduction, and thus, the air present above the land heats up quickly and expands. The heating of air above the land reduces its density; hence the light air rises. The space created by the rise of hot air is filled by the cool air, which leads to the development of sea breeze adjacent to the water bodies. 

However, during nighttime, the land cools off quickly while the water stays warmer, and as a result, the cycle is reversed.

Development of Trade Wind due to Convection.

Another phenomenon in which natural Convection notes an important part is the development of trade wind from north-east to the equator. 

The reason behind the creation of trade wind is due to the unequal heating of the equatorial and Polar Regions of Earth. If we observe, the air on the regions near the equator is hot compared to the air present near the pole of the Earth. Due to heat transfer, a convection current will be set up between the equatorial region and the poles. Thus the hot air from the equator will travel to the poles. In contrast, the cool air will descend and streamline towards the equator. But since the Earth is constantly rotating on its axis, the speed of air near the equator is around 1600kmph while that at the pole is zero. Thus instead of travelling straight to the poles, the air travels 30 degrees North latitude and returns to the equator. These winds are called trade winds.

Conduction

Conduction is the transfer of heat in the adjacent parts of a body due to the difference in temperature. For instance: – consider a metal rod whose one end is heated by putting it over a flame. Soon enough, the other end of the rod will also be heated to an extent where you won’t be able to hold it with bare hands. In the case of a metal rod, the heat transfer occurs from the heated end towards the cooler end. The heating of the rod is one of the best examples to get knowledge about the process of conduction.

Radiation

Both Conduction and Convection require some material as a medium for transporting heat. However, if we observe, the Earth receives the sun’s heat quickly. This is mainly due to the third type of heat transfer called radiation. Radiation doesn’t require any kind of medium to transfer the heat to a body, and thus the heat which is radiated is called radiant energy.

Conclusion

Heat is a type of energy that flows between the body and the surroundings due to the difference in temperature. The Process of heat travelling from one body to another is thus called heat transfer. However, to understand heat transfer in-depth, it is necessary to know what is conduction? What is Convection? And what is radiation? Moreover, to understand the concepts of sea breeze and trade winds, it is necessary that an individual have in-depth knowledge about Convection and its types. Thus, to have comprehensive knowledge about the phenomenon of heat transfer, it is essential to know the different modes of heat transfer.