ABSTRACT
This chapter discusses the effect of heat transfer, namely temperature changes, changes of state, expansion and pressure changes. The rate of heat transfer by conduction is proportional to the temperature gradient in the heat flow direction and to the cross-sectional area of the solid through which the heat flow occurs that is the solid area at right angles to the heat flow direction. This is known as the Fourier law of heat conduction. Heat transfer to a substance which results in a change of temperature is said to be sensible heat, such a transfer increasing the energy of its atoms or molecules. The energy gained by the body is used to change bonds between atoms or molecules. Heat which results in no temperature change is called latent heat. The specific latent heat of fusion is used when the change of phase is from solid to liquid and the specific latent heat of vaporisation for the change from liquid to vapour.
