The NCW Physics department have got a new Van de Graaff generator, and have been busy investigating the effects of charging a student!
A Van de Graaff generator is an electrostatic generator which removes electrons from the dome, moves them along a belt and takes them to the bottom of the generator. The positive charges left are spread out on the surface of the sphere.
Mr Stark charged up the Van de Graaff by spinning a wheel which turned the belt and transferred the electrons away from the metal dome at the top, making it positively charged. We could soon hear and then see huge sparks between the big globe and onto the discharge ball! We made a particle accelerator.
Sixth Form student Madiha was very excited to have a go. She stood on a plastic tray while holding onto the globe and Mr Stark charged it up again. This time the charge transferred to her – don’t worry, that plastic tray she was standing on would definitely prevent any mishaps! The generator can charge upto 200,000V, but only a tiny current can flow from the dome so it is totally safe.
When the Van de Graaff generator starts charging, it transfers the charge to the person who is touching it. Since Madiha’s hair strands were getting charged to the same voltage, they tried to repel each other. This is why her hair started moving.
Mr Stark’s Science Club on a Friday lunchtime have also been investigating the new Van de Graaff.
It’s definitely a “positive” success!