First start by rubbing the balloon on wool or your hair or your dogs hair.
When you rub the balloon on your hair, tiny parts of the atoms in your hair, called ELECTRONS, collected on the balloon. These electrons have a NEGATIVE charge. Now that the balloon has a negative charge, it is attracted to things that have a POSITIVE charge.
When you bring the negatively charged balloon near the faucet it is attracted to the POSITIVE force of the water. The attraction is strong enough to actually pull the water towards the balloon as it is flowing! It is thanks to what scientist call static electricity.
Static Electricity with a soda can
Using the same balloon with negative electrons makes it possible to pull very light objects (with a positive charge) toward them – like the soda can. You can control the can by moving the balloon away from the can and back again.