By touching the two metal strips on this ball and the LED lighting up as a result, kids can learn about the idea of an open and closed circuit. This will also teach them about conductivity as their body is being used to conduct and transfer electrons from one strip of metal to the other. This ball can be used with a group of people so long as the people are all touching each other and the metal strips. Furthermore, once the kids get bored with learning about the nature of electricity, they can throw the ball around and get some exercise.
This ball will be made of plastic for the housing while copper will be used for the metal components. The circuit will have a low current and voltage to prevent injuries. It will also be 4 inches in diameter to prevent choking.