There are many ways heat is transferred from one object to another and within the very same object that is being heated or is already hot. Heat can be transferred through conduction which is basically by the virtue of touch or being in contact. When a heat source or a heated object comes in contact with another object that is less hot or cold, then the contact will lead to transfer of heat from the hot object to the cold object. This is conduction. The other method is convection.
Convection Currents: Explained!
Convection is a process of heat transfer where instead of two objects being in touch, the molecules of an object being heated or already hot transit heat within the object and then to the environment. Convection often stems from conduction. For instance, when you boil a pot of water, you are essentially heating the pot of water through conduction as the heat source is in direct contact with the pot. Once the water gets heated up, the hot molecules of water rise up forcing the dense cold molecules of water on top to move down. This transfers heat. When the heated molecules cool down in the absence of a heat source, they would move down allowing the heated molecules at the bottom to rise up.
This movement of hot and cold molecules will create a current and this is known as convection current.
Types of Convection Current
Convection current develops in the mantle of the earth due to the repeated heating and cooling cycles of the magma. This also acts as the foundation of the plate or tectonic movements. Convection currents develop in the atmosphere as well resulting in the formation of winds and clouds.
When the air gets heated up at a place or in an area, it gets hot because the gaseous molecules in the air get heated up and they rise up allowing the cold air around the area to take its place. The cold air gets heated up and rises creating a cycle of heated air rising up and cold air taking its place. This creates wind. The difference of temperature in the air or atmosphere and thus the difference in air pressure or atmospheric pressure create winds. Convection currents also result in precipitation, including snowfall. The formation, movement and eventual precipitation of the clouds are all by the virtue of convection currents.
It must be noted that convection currents apply to liquid or gas, not solids.