Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields. The interaction between charge and field is the source of the electromagnetic force, which is one of the four fundamental forces.

Electric charge which builds up on an insulator and is thus unable to flow is termed static electricity. Like-charged objects repel and opposite-charged objects attract one another. Static electricity is a class of phenomena involving the imbalanced charge present on an object, typically referring to charge with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. Static electricity can be seen at work when hair is combed on a cold, dry day. As the comb is pulled through the hair, strands of hair stand out stiffly. Some kind of force seems to pull the hair upward toward the comb.

Rubbing action creates charged objects because it tears electrons loose from some kinds of atoms and transfers them to others. In the case of plastic rubbed with wool, electrons are taken from the wool and pile up on the plastic, giving the plastic a net negative charge and leaving the wool charged positively. When glass is rubbed with silk, the glass loses electrons and the silk gains, producing glass that is charged positively and silk that is charged negatively.

Picking Up Paper Bits with a Comb

Tear some paper into small pieces and put the down on a table. Comb your hair. Move the comb close to the paper pieces. The pieces of paper should jump up to the comb!

Deflecting Water with a Comb

Turn on a water tap so that the water flows in a narrow stream. Comb your hair. Move the comb close to the water but don't let it touch. You should see the water stream move towards the comb!

Sticking Balloons to the Wall

Blow up a balloon, and rub it on your hair. Touch the balloon to the wall or ceiling. It should stick there!