Examples of convection work on the principle of heat transfer. There are three basic modes of heat transfer namely, radiation, conduction and convection. Radiation is defined as the transfer of energy to or from a body by means of the emission or absorption of electromagnetic radiation by rays, waves or particles. Conduction is defined as the transfer of heat between two objects when they are in contact with each other. Contact here means physical contact. Conduction is also called as diffusion. Now before we look into the examples of convection, let us go through a bit of the basic information related to convection.
What is Convection?
Convection is a term related to physics and more precisely, fluid mechanics. The definition of convection, which is also its literal meaning, is the transfer of heat through a fluid, in either forms, liquid or gaseous, which is caused by molecular motion. The motion of the molecules that transfer heat can be of two types, viz., in bulk or by individual particles. The former is called as advection and the latter as diffusion.
This principle of heat transfer works not only in cases of liquids and gases, as mentioned above, but in solids too. But the difference between both are that the heat transfer in solids is called as conduction. Examples of convection in everyday life are in the forms of electronic items that work on radiation, microwaves, etc., as we will see in the following paragraphs.
However, it is interesting to note that the examples of convection in general can be as obvious as tornadoes and hurricanes, and as subtle as the microwave oven in your home. Here we will look only at the examples of convection heat transfer in our day to day life.
Examples of Convection
Some examples of convection currents are very common in our life, like the following:
- Microwave ovens
- Melting of ice
- Hot air balloon
The microwave oven is the most common example of convection in kitchen appliances. It works on the principle explained above and its working can be noticed by observing a plate of food given for reheating. What exactly happens is the air inside the microwave oven is heated and then the convection currents are forced into the food item. If you put soybeans in a bowl of soup, you can actually see the liquid being boiled and if you immediately check the beans, they would still be in the normal temperature or definitely lesser than the soup. Liquids are heated much faster than the solid beans due to the convection currents.
Melting of ice is another example of convection that we see daily. The transformation of ice from the solid cube into the liquid form, water, happens because of the heat of our palm. Our body temperature is higher than the temperature of ice. And the heat waves or heat currents have a tendency to flow from higher to lower temperature gradient. That means heat flows from our body through the palm and penetrates the ice thus causing the ice to change its form and turn into water. This principle remains the same in case of hurricanes and tornadoes too.
Then comes the example of the hot air balloon. Using convection, the hot air balloon is seen to rise above the ground surface and float in the air. The mechanism behind is that the fire inside the balloon heats the air which in turn is trapped by the balloon and does not let the hot air escape like shown in the picture above.
So these were some of the common examples of convection in everyday life. Hope this article helped you to understand the science behind convection and the basic principle of heat transfer.