Chapter 8 Transfer Of Thermal Energy

Transfer of thermal energy consists of conduction, convection and radiation.

Conduction occurs in all three states of matter, solid, liquid and gas.It is the transfer of heat energy due to the transfer of kinetic energy. Particles vibrate more vigorously after being heated forming a chain effect resulting in the particles of the whole objects vibrates more vigorously as a whole. However, the ability for an object to conduct heat through conduction is determined by how the particles align themselves. Hence metal will conduct heat better than a piece of wood.

For convection, it works by the theory that hot gas/liquid rises and cold gas/liquid sinks. When an object is being heated unevenly, a hot and cold region will be formed. Hence convection will occur. However, it only applies for gas/liquid as the particles in them are not in a fixed position as the force of attraction between them is weaker. Hence the mobility allows convection to occur.

For radiation, it is due to the electromagnetic wave. Infra-red waves allow the transfer of heat and it is not restricted by any medium unlike conduction and convection. However, the absorption of radiation is affected by several factors such as colour, texture of the object and surface area.

Having said so, the theory of thermal conduction has benefited man-kind in a lot of ways. For conduction, the cooking pans we use make full use of the theory of conduction. The metal part of the pan allows heat conduction to cook food and also allow even distribution of heat throughout the pan. The plastic handles protect us from the heat and let us handle the pan when we are cooking. Without which, we will not have the luxury to being able to cook our food so efficiently.

For convection, ill relate it to cooking again since I aspire to be a good housewife. When we cook our noodles or soup, the heat in the water is transferred through convection. Without which, the process of conduction will be very slow. Just imagine if everyone is to take over one hour to cook a packet of noodles, wont my future husband starved to death by the time I finish? Hence convection plays a very important role in our daily livelihood and also in many industries.

For radiation, using cooking as an example again, our microwave oven makes use of this aspect of thermal conduction. The microwave oven produces microwave which heats up our food quickly. This provided much convenience and saved a lot of our time.

In conclusion, making use of the physics theory of conduction, convection and radiation in our daily lives helps to reduce a lot of troubles. Not only in our household, but these theories are also proved useful in many industries and factories.