Describe an experiment to demonstrate that there are two kinds of charges.

The following experiment demonstrates that there are two kinds of charges:

1. Take a glass rod A1. Rub it with silk and suspend it with a thread. Take another glass rod B1. Rub it with silk and bring it near one end of the suspended rod A1. It is observed that the suspended glass rod A1 gets repelled.
2. Take an ebonite rod A2. Rub it with fur and suspend it with thread. Take another ebonite rod B2. Rub it with fur and bring it near one end of the suspended rod A2. It is observed that the suspended ebonite rod A2 gets repelled.
3. Suspend glass rod A1 rubbed with silk and bring ebonite rod B2 near one end of the suspended rod A1. It is observed that rod A1 gets attracted towards rod B2.

In all the above steps, if the rods have not been rubbed with silk or fur, no repulsion or attraction between the rods would have been observed.

Conclusion — From this experiment we conclude that:

1. There are two kind of charges.
2. Like charges repel and unlike charges attract each other.