Pith-ball electroscope consists of a pith-ball suspended with a silk thread from an insulating stand.
To find whether a body is charged or uncharged we bring the body close to the pith-ball without touching the ball.
If the pith-ball shows any movement, then the body is charged.
On the other hand if the ball remains stationary the body is uncharged.
To find whether a body is positively charged or negatively charged, we charge the pith-ball either positive or negative by the method of conduction.
Now bring the body whose charge is to be identified near the pith-ball.
If the pith ball moves towards the body, they have opposite charges. (If the pith-ball is positively charged then the body is negatively charged and vice versa).
On the other hand if the pith ball moves away from the body, they have some charges.
