1) Fill plastic tube with small amount of styrofoam balls.
2) Close end of tube
3) Rub the outside of the plastic tube with the styrofoam balls inside with wool, your hair or something to charge it up for about 15 to 30 seconds.
You should start to see the styrofoam balls jump, dance and then stick to the walls of the plastic tube.
By rubbing the tube we transferring electrons from the wool cloth to the surface of the plastic tube. The electrons now on the surface of the tube are attracted to the protons in the styrofoam balls.
Opposites attract each other. Hence the name of the experiment. So we have electrons which have a negative charge on the surface of the plastic tube and protons that have a positive charge on the styrofoam balls. When they get close to each other the attraction makes them, jump around then stick to the plastic tubes sides.
And the negatively charged electrons on the surface of the plastic tube repel the
negatively charged electrons inside the styrofoam balls. Since the negative electrons in the styrofoam is being repelled, the positive charges in the styrofoam balls are closer to the plastic tubes sides. When the positive charges styrofoam balls and negative charges plastic tube get close they attract and stick to each other.