Rub each balloon on the sweater, so that they each have negative charges on them. Place one balloon as far away from the sweater as possible on the right. Then bring the other balloon close to that balloon. What happens and why?
When the balloons are rubbed on the sweater, they acquire a negative charge due to the transfer of electrons from the sweater to the balloons. As a result, the balloons become negatively charged objects.
When the two negatively charged balloons are brought close to each other, they repel each other. This repulsion occurs because both balloons have acquired a negative charge. According to the principle of electrostatics, objects with the same charge repel each other, while objects with opposite charges attract each other.
This repulsion is due to the fact that the balloons have acquired excess electrons and thus possess a negative charge. The excess negative charges on each balloon create an electrostatic force pushing them apart, causing the repulsion observed.
The force of repulsion is stronger when the balloons are closer to each other and diminishes as they move farther apart. Therefore, if one balloon is placed as far away from the sweater as possible on the right, and the other balloon is brought close to it, the balloons will repel each other and start moving away from each other.