Inside the plasma ball, very low-pressure gas surrounds the electrode and the atmosphere around it. The electrode creates a high-energy electric field, which moves electrons (particles of atoms, with a charge of -1) through the gas. As electrons move, they collide into nearby neighbor atoms and give them extra energy as well. Therefore, these atoms get rid of excess energy by means of heat and light. This is why there are long streams of lightening between the electrode and the top of the ball. If a person put his or her hand on the ball, the light will move toward the hand, because it is the easiest route by which the electrons can go to the neutral ground, where they can spread out.