Radiation is said to be the transfer of heat between two objects without any medium between them , that can help them in heat transfer . Hence radiation is said to be the direct transfer of heat between two objects . For example the heat we get from the sun can be said to be from radiation as there is nothing between us and the sun that is helping the sun's heat reach us . The sun's heat reaches Earth directly . This is an example of radiation; which is a type of heat transfer .