Materials Wool PVC pipe or plastic comb String Lighter Procedure Hang the string from an elevated position. Leave the bottom end free. Rub the PVC pipe with wool. This deposits negative charges, or electrons, onto the surface of the PVC pipe. Place the side of the pipe that is rubbed near the string. You should
A thin stream of water can be easily bent using a plastic comb or ruler which was previously rubbed with wool. This demonstrates the attractive forces between unlike charges.
- Plastic ruler
- Water from a tap
- Turn on the faucet for the thinnest stream of water with a consistent flow.
- Rub the plastic ruler with the wool.
- Place the part of the ruler which was rubbed near the stream of water without touching.
Water molecules are polar in nature, which means that one side (where the oxygen atoms are) is more negative while another side (where the hydrogen atom is) is more positive. When wool is rubbed with plastic, it deposits electrons on the ruler.
The electrons will remain on the plastic as it is a poor conductor of electricity. When placed near the stream of water, the water molecules reorientate themselves such that the positive pole of each molecule is now nearer to the ruler than the negative pole.
The resulting attractive forces are stronger than the repulsive forces as the forces between charges decrease when the distance apart increases.
An electroscope is a device that can be used to detect or measure the amount of charge in its vicinity. One of the earliest electroscopes is the gold-leaf electroscope which was invented by a British clergyman Abraham Bennet. This is a cheaper model of the leaf electroscope made using aluminum foil. Materials Paper clip Aluminum