Silk Braid Electroscope

The structure: a metal pillar is fixed on an insulating base. On the top of the metal pillar, some silk braids are clamped by a pair of metal piece. The silk braids are in Free State. When the silk braids are electrified, they are divergent. And when the silk braids are not electrified, they are convergent. This apparatus is used to demonstrate the figuration of the electric line of force. And cooperated with metal cage, it can do the electrostatic screening experiment too