Excited about the Van de Graaff generator when we touch it.

The Van de Graaff generator is a great machine that was designed by Robert van de Graaff in the year of 1929. When we touch this van de Graaff machine really we excited by the positive charge. You can see in this picture, that when the girls were touching this machine their hair had tempered. Because the positive charges are spread over this machine. We really enjoy it when we feel or understand physics. The physics of this machine is not the easiest and most understandable one. But we can see and touch easily as same as all science concepts and principles are difficult. But we can able to understand we may easily create science products.

The principle of the Van de Graaff generator is electrostatic induction and the action at points. This generator produces positive charges very large.

A large hollow spherical conductor is fixed on the insulating stand. It has two pulleys and is fixed with a belt made up of silk or rubber material. The comb-shaped metallic conductors are fixed near the pulleys. Because of the sharp edges attracted negative charges and repelled positive charges. We need positive charges for nuclear disintegration and other applications.

The pulleys are driven continuously by the electric motor. Due to the high electric field near the comb, the air between the belt and the lower comb gets ionized. The positive charges are pushed towards the belt and negative charges are attracted towards the comb.

 The positive charges stick to the belt and move up. When the positive charges reach the upper comb, a large amount of negative and positive charges are induced on either side of the upper comb due to the electrostatic induction. The positive charges are pushed away from the upper comb and they reach the outer surface of the sphere. 

Since the sphere is a conductor, the positive charges are distributed uniformly on the outer surface of the hollow sphere. At the same time, the negative charges in the belt are due to corona discharge before it passes over the pulley. This process continues until the outer surface produces the potential difference of the order of 10⁷ which is the limiting value. Van de Graaff generator is used to accelerate positive ions for nuclear disintegration.

Usually, this generator is used to generate positive charges for nuclear disintegration, generating some particles like protons and deuterons which produce beams. The beam is used to treat cancer.