Step 3

Repeat step one - slowly moving the inflated balloon towards the empty can. What happened?

The balloon should "pull" the can to itself as it nears the can.

How does it work?
It’s all because of static electricity.  Static electricity is a force that is created when objects lose or gain electrons.  An atom is made up of electrons (negative charge), protons (positive charge) and neutrons (no charge or neutral). The balloon starts off neutral. When you rub the balloon across the top of your head, it picks up electrons from your hair. Now it has more electrons (negative) than protons (positive) so it has an overall negative charge. In our static activity we discuss how opposite charges attract each other and like charges repel each other.

So what about the soda can? Is it positive or negative? You might assume it is positive since we know the balloon is negative. But this is where it gets interesting. Any charged object (positive or negative) will attract a neutral object (no charge). That is why you can take a charged balloon and "stick" it to a neutral wall. This has to do with "induction" which we do not have time to discuss here.


So ...
Opposites attract
Likes repel (see static activity)
Charged objects attract neutral objects.

The balloon is charged (negative) and the can is neutral so the balloon attracts the can.

Try this:
Try and "walk the can" with your invisible leash (balloon). Can you lead the can across the table without touching it? Can you make the can "turn"?