Thursday, June 10, 2021 - 08:46

I bet you do! Have you ever seen or touched one of those metallic looking globes that makes your hair stand on end? That device is called a Van de Graaff generator.


So how exactly does a Van de Graaff generator work? Let's explore!


To understand the Van de Graaff generator and how it works, you need to have some understanding of static electricity. Most of us are familiar with static electricity - we can see and feel it in the winter or very dry conditions. On dry winter days, static electricity can build up in our bodies and cause a spark to jump from our bodies to pieces of metal or other people's bodies. We can see, feel and hear the sound of the shock.


Now that we discussed electrostatics and static electricity, it is easier to understand the purpose of the Van de Graaff generator. American physicist Robert Jemison Van de Graaff invented the Van de Graaff generator in 1931. Which has the ability to produce extremely high voltages -- as high as 20 million volts! Yikes! Van de Graaff invented the generator to supply the high energy needed for early particle accelerators. These accelerators were known as atom smashers because they accelerated sub-atomic particles to very high speeds and then "smashed" them into the target atoms. This led to other subatomic particles and high-energy radiation such as X-rays! The ability to create these high-energy collisions is the foundation of particle and nuclear physics. Whoa!
 
Put simply, a Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, creating very high electric potentials. It produces very high voltage direct current electricity at low current levels. Neat, huh?


The largest air-insulated Van de Graaff generator in the world, built by Dr. Van de Graaff in the 1930s, is now displayed permanently at Boston's Museum of Science. With two conjoined 15 foot aluminum spheres standing on columns 22 ft tall, this generator can often obtain 2 million volts. Shows using the Van de Graaff generator and several Tesla coils are conducted two to three times a day. Many science museums, such as the American Museum of Science and Energy, have small-scale Van de Graaff generators on display, and exploit their static-producing qualities to create "lightning" or make people's hair stand up.
Van de Graaff generators are also used in schools and science shows around the world.

Does your school or science room have a Van de Graaff generator?

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  • STEM Fuse Team