Located in Electrostatics Cabinet, A1
Used to show presence, and perhaps sign, of electric charge.
Rub rod with fur, touch rod to knob on top of electroscope, remove rod. The leaves diverge, indicating non-zero charge on electroscope.
Rub same rod with fur, bring it near but not touching knob. Leaves diverge further due to induced charge.
Rub the other rod with the fur, and bring it near but not touching. Leaves droop due to induce charge.
Rub the other rod with the fur, touch the rod to the knob, and remove the rod. The leaves droop, indicating decreased or zero charge on the electroscope.
The department has several electroscopes, of which the red-and-gold electroscope shown in the picture seems to be the most sensitive.