Then let the balloon hang freely. Bring your sock-covered hand near the balloon. Try rubbing both balloons with the sock and then let them hang near each other. Look for other examples of static electricity around the house. All materials contain millions of tiny particles, called protons and electrons, that have electric charges.
Protons have positive charges, and electrons negative ones.
Usually, they balance each other, but sometimes when two surfaces rub together, some of the electrons rub off one surface onto the other and we can have static electricity.