Convection is the transfer of energy by movement of a medium, whereas radiation<span> is the transfer of energy by, well, thermal </span>radiation<span>. </span>Conduction<span> also requires a medium, but, again, it is a fundamentally different mechanism than either convection or </span>radiation<span>; in this case it is the transfer of energy through a medium.</span>
In radiation, we don't need medium to conduct heat or energy but in conduction we need medium to conduct energy or heat ! conduction is done by contact as in radiation there is no contact !
