Forms of Energy
Energy appears in different forms such as thermal energy, light energy, mechanical energy (kinetic energy and potential energy),electrical energy, nuclear energy and others.
All forms of energy are of the same origin, so any one of the forms
can be converted into another. It is not casy to provide a gencral definition for energy. However, we can use the definition that people agreed upon form their daily experience. This is: Energy is the ability to do work.
The need for energy expands with the growth and evolution of human communities. Originally human needs were mainly concerned with energy in the form animal and plants.
With the development of these communities and their technology, a
great change in energy requirements and its sources took place. In the nineteenth century wood played an essential role as a prime source of energy. During the twentieth century, one got used to petroleum as a prime source of energy. Because of the rapidly expanding rates of energy consumption, the petroleum stocks can last only for about 50 years and so it is now essential to look for substitutes.
Some of the important steps taken in this direction are:
1) The search for new sources of coal and dependence upon it as a
temporary substitute for petroleum.
2) The use of nuclear energy to generate electricity to run factories
as well as other domestic uses.
3) The expansion in the use of natural and even artificial water falls
to generate electricity. This is called hydroelectric power
4) The use of chinnging sea levels due to tidés to generate electricity
5) Making use of wind to run windmills connected to electric generators.
6) The wideness of fertile soils as a guarantee for man's vital energy supplied by nature.
7) Good use of solar energy which is considered to be a key part of future energy policy, especially in hot countries.
Again, energy has different forms, one form of energy can often be changed to another which is more useful to us but we cannot actually create energy. This principle is known as the law of conservation of energy. Energy is neither destroyed nor created, but changes from one form to another. For example potential energy and vice-versa; in a way
that the total energy is constant.
In common with the rapidly shifting pattern of all engineering education, the requirements to be met in teaching energy conversion processes have changed significantly. Emphasis must be placed on the dynamics of energy conversion devices and systems. The theory must be developed from simple beginnings in such a manner that it can readily be applied to new and complex situations. Physical concepts must be highlighted and not subordinated to mathematical techniques, for these concepts, rather than routine analysis, usually underlie creative engineering and become the most valuable and permanent part of a student's background. Attention must be given to the art of reducing a practical situation to a mathematical model. Opportunity must be presented in text, examples and problems for applying, illustrating and developing modem engineering and analytical techniques.