Pith Ball Electroscope (0811) Specifications : Size: 11 x 13 x 26 cm – Weight: approx. 100 g. The Pith Ball Electroscope is a simple instrument for demonstrating electrostatic force. With some simple rods of different materials such as perspex, PVC or glass and a piece wool or silk surface, you can charge one of the spheres in the electroscope. After, the spheres will have different charges and will repel each other. LAWS & PRINCIPLES INVESTIGATED : • Electrostatic charge • Electrical sparks. Qty :