What you need:
A plastic spoon, woollen cloth and a plate of of puffed rice.
What you do:
Hold the spoon over the plate of puffed rice.
Rub the spoon with a woollen cloth. Then hold it over the plate of puffed rice.
What you see:
Nothing happens when you hold the plastic spoon over the plate of puffed rice but when you rub the spoon with the woollen cloth and then hold it over the puffed rice, the grains leap onto the spoon and then fall down in different directions.
Why does this happen?
When the spoon is rubbed with woollen cloth, it gets negatively charged. The grains of puffed rice are attracted to the negatively charged spoon because the charged spoon induces and opposite charge-positive charge-in the grains by induction. Opposite charges attract and hence the grains leap to the charged spoon. The minute they touch the charged spoon, the grains get the same negative charge as spoon because of conduction. Similar charges repel each other and the now negatively charged grains fall off from the spoon in different directions.
Picture Credit : Google
