ABSTRACT
Heat is a form of energy and is measured in joules. Temperature is the degree of hotness or coldness of a
Why it is important to understand: Heat energy and transfer This chapter defines sensible and latent heat and provides the appropriate formulae to calculate the amount of energy required to convert a solid to a gas and vice-versa, and also for other combinations of solids, liquids and gases. This information is often required by engineers if they are required to design an artefact (say) to convert ice to steam via the state of liquid water. An example of a household requirement of when this type of calculation is required is that of the simple domestic kettle. When the designer is required to design a domestic electric kettle, it is important that the design is such that the powering arrangement is (just) enough to boil the required amount of water in a reasonable time. If the powering were too low, you may have great difficulty in boiling the water when the kettle is full. Similar calculations are required for large water containers, which are required to boil large quantities of water for other uses, including for kitchens in schools, to make tea/coffee, etc., and for large hotels, which have many uses for hot water. The chapter also describes the three main methods of heat transfer, namely conduction, convection and radiation, together with their uses. All of this is fundamental in the design of heat engines, compressors, refrigerators, etc.
