Plasma Ball
A plasma ball is a decorative physics gadget that produces spectacular and colorful lightning inside a glass sphere filled with gases...
A plasma ball, also called a plasma globe, consists of a base and transparent glass sphere placed around an electrode. When the plasma sphere is turned on, continuous filaments of different colors can be seen extending from the electrode to the sphere surrounding it. One of the most important parts of this device is the Tesla coil which generates a strong electric field between the electrode and the sphere. A Tesla coil is a simple resonant transformer that can produce very high voltages. If the electric field is strong enough, the gases inside the sphere become ionized. That means many free electrons are created, and the gases start to conduct electricity. Electrons naturally want to move toward the ground, so we can see plasma filaments floating to the glass sphere. If, for example, we touch the sphere with our finger, we create an easier path for the electrons to reach the ground, and the filament gets much brighter. You can do all sorts of interesting tricks with the plasma ball, such as watching it react to sound or lighting up a light bulb in your hand.