Van de graff generator discharge:
A "Van de Graaff generator" is a device that has been designed to produce static electricity. The van de graff generator works on the principle of "electrostatic induction", due to which electrostatic potential is constant at any other point throughout the conductor.
It is also observed that van de graff discharge takes place in air or gases which are readily pointed at the conductors. Discharge occurs in the air because most of the static charges get removed by the gases present in the air.