the.com/van de graaff generator

means An electrostatic machine that uses a moving belt to pile up massive static charge on a hollow metal dome, which it will happily discharge as a spark — or your standing-up hair — the moment it gets the chance.

from Named for Robert Van de Graaff, the American physicist who built the first version around 1929 while trying to create a compact, high-voltage source for nuclear physics experiments. The design itself is older in concept — Lord Kelvin had tinkered with charge-carrying mechanisms decades earlier — but Van de Graaff's belt-driven version, developed at Princeton, became the one that stuck, literally powering early particle accelerators before it became a classroom staple for making hair stand on end.