The Smithsonian 5" plug in Plasma Ball is awesome for the little Scientists! Touch the Plasma Ball and see the light gravitate towards your hands. Its an incredible Smithsonian Plasma Light show at your fingertips! Control lighting with this desktop Plasma Ball . A small Tesla coil generates a large electrical potential difference, which tries to even itself out by discharging in the same way that a cloud discharges lighting. Watch the Plasma streams move toward your uncharged finger as you touch the ball, or make them respond to sound and music. Includes STEM Educational Content. Includes Plasma Lamp and UL adapter. requires 3 AA Batteries( not included).