Chemicals are essential building blocks for everything in the world. All living matter, including people, animals and plants, consists of chemicals. All food is made up of chemical substances. Chemicals in food are largely harmless and often desirable – for example, nutrients such as car…

The electric wires used in domestic wiring are made of copper metal because copper is a good conductor of electricity having very low resistance. Now, the copper wires chosen for household wiring are of such thickness so as to allow a certain maximum current to passe through them. If th…

A motor is a device which electrical energy into mechanical energy. Every motor has a shaft or spindle which rotates continuously when current is passed into it. The rotation of its shaft is used to drive the various types of machines in home and industry. Electric motor is used in elec…

Those sources of energy which are being produced continuously in nature and are inexhaustible, are called renewable source of energy. For example, wood is a renewable source of energy because if trees are cut from the forests for obtaining wood, than more trees will grow in the forest i…

The ability to see is called vision. It is also eyesight. Vision is known as 'drishti' in Hindu.  Sometimes the eye of a person cannot focus the image of an object on the retina properly. In such cases the vision of a person becomes blurred and he cannot see either the distant o…