Convection is a mode of heat transfer that occurs in fluids.
There are three types of heat transfer:
conduction convection and radiation
Conduction is a mode of heat transfer that involves an actual contact between the molecules of the medium. It occurs mostly in solids
Radiation uses electromagnetic waves to transfer heat between two bodies or places. It does not require a material medium. The heat of the sun reaches us by radiation.
Convection is a mode of heat transfer in fluids. It involves the density differences between hot and cold liquids and gases.
During ice ages, the most characteristic change to the planet has been the formation and spread large ice sheets and glaciers across much the Northern Hemisphere.
