Create Static Electricity
2 inflated balloons
Rub the balloons, one by one, against the woolen fabric and then try moving the balloons close to each other. You will see that the balloons tend to move away from each other.
Put an aluminum can on a table. Rub one of the balloons against the woolen fabric or your hair and then, bring it close to the aluminum can. You will notice that the aluminum can rolls toward it and follows the balloon even if it is moved away from the can.
How does this work?
Rubbing the balloon against the woolen fabric or hair, creates static electricity. It is a process whereby negatively charged electrons jump into positively charged ones.
In the first step, both the balloons were negatively charged on being rubbed against the woolen fabric. Therefore, they were repelling each other. This proves that similar poles repel each other.
In the second step, the aluminum can is drawn to the negatively charged balloon as the area near it becomes positively charged. This proves that opposite charges attract.