Work is done whenever the application of force produced a change. It may consist of moving a load through some distance or squeezing or cutting of the objects. Energy is needed to do work. Energy is also needed when we heat objects. For example, cooking of food or smelting a metal requires heat energy. The need for energy would go up with the increase of man’s needs. In the early day, the only source of energy available to man was his own muscular energy. He could replenish this energy by eating food.
Later on, he discovered other sources of energy. He learnt to build fire by burning wood, to tame animals like bullocks, camels, horses and elephants and use their muscular energies. The sources of energy were very limited for early man, but, he learnt to tap the energy of the wind. He started to utilise the energy of wind in the sailing of boats, such sailboats could spread their sails, catch the wind and make the sailboats move. The principle of boat sailing by wind power looks simple. But great skill is required to make use of the wind. The wind does not always blow in the same direction. In fact, skilful use of a set of sails and a rudder is necessary in order to steer a sailboat. Windmills also worked with the help of wind energy. Similarly, water flowing down the stream in large rivers was used for transporting logs. Water wheels were invented to utilise the energy of flowing water. In these cases, the flowing water and blowing wind have been converted into a resource.
Thus, we have seen that each type of technology involves the application of science, its laws and principles to everyday life. It is because of this fact that technology is often called applied science. The level of technological advancement is closely related to the level of scientific knowledge. Every discovery in science adds something to technology. Therefore, the advancement of technology depends upon the discoveries of science. For example- in the early days, we had not much knowledge and understanding of science. As a result, the technology of a few centuries ago was also not very advance. The source of energy then were only muscle power, firewood, wind and water. The discovery of coal (a fossil fuel) brought a revolution in the field of energy. It became one of the most important resources and used to be called black diamond. Many engines were operated using the energy of combustion of coal as the fuel. The early railway engines used the coal to heat water and to produce steam. The expansion of steam caused the movement of the pistons and the wheels. The discovery of petroleum and natural gas (other fossil fuels) created a great stir in the world. Their use was more efficient and convenient than coal. The use of this energy advanced mechanical engineering- the technology of engines and motors. Later on, new types of engines were invented, so that, these fuels could be used more efficiently. Technology advanced further with the discovery of electricity and magnetism and the fields of electrical engineering and electronic technology were established. The latest breakthrough is the atomic energy which has given us an almost unlimited resource. Technology has made tremendous progress due to atomic energy.
Landmark discoveries and inventions lead to new technologies. In their turn, these new technologies change the course of development of human societies the world over. For instance, a society that learnt to tame fire first advanced sooner than one that did not. An agricultural society has greater chances of all-round development than a nomadic tribe. Similarly, the discovery of the preparation and uses of metals, the discovery of gun powder, of the steam engine and son on, have deep impact on the advancement of human society.