Hand touching a plasma globe. The device displays glowing tendrils of plasma within a glass sphere. At its centre is a high-voltage electrode, and the sphere is filled with a mixture of nobles gases, such as neon and argon. The high voltage breaks down the gas into a conducting glowing plasma. The glowing tendrils are hotter than the surrounding gas, and rise through it. If a conducting object is placed against the outside of the sphere, such as the hand at bottom here, it provides a path of less resistance and attracts a bright stream of plasma. The plasma lamp was invented by Nikola Tesla, but this design was built and popularised by Bill Parker in the 1970s.