Now reset the balloon. Again, collect the blue negative charges from the sweater, by rubbing the balloon on the sweater. Even bring the balloon close to the wall again. What do you notice about the movement of the negative charges in comparison to the positive charges? Explain why.
When the balloon is rubbed on the sweater again, the blue negative charges will be collected on the surface of the balloon. As the balloon is brought close to the wall, the negative charges on the balloon will be repelled by the negative charges on the wall. The movement of the negative charges will be similar to the movement of the positive charges in the previous scenario.
The reason for this is that like charges repel each other. The negative charges on the balloon and the wall both have the same charge, which is negative. Therefore, they experience a repulsive force and move away from each other. This is why the blue negative charges on the balloon move away from the wall when the balloon is brought close to it.