Van de Graaff

Robert J. Van de Graaff was an American physicist who, in 1929, invented a device called the Van de Graff generator. You may have seen, or even used, a Van de Graaff generator in the classroom at school. It is an electrostatic generator which uses an acrylic roller and rubber belt to amass very high voltages which are accumulate in a hollow metal sphere.

 

How a Van de Graaff generator works

• Friction between the Acrylic Roller and the Rubber Belt causes the Acrylic to become positively (+) charged
• This attracts Electrons to the tips of the lower comb
• The rubber belt picks up the Electrons and carries the Negative (-) charge up to the upper comb
• The upper comb picks up the same electrons and places it on the collecting sphere
• Placing a grounded electrode next to the generator will cause a spark, draining the excess charge
• The Van de Graaff Generator must recharge before another spark can be made

Van de Graaff Generator image courtesy of science-resources.co.uk

 

 

Tags: what is static electricity; how does static electricity work; uses of static electricity; what is static electricity; earthing; charging by induction; friction; how does a Van de Graaff Generator work