Ever had this happen in your house - something gets broken and Dad goes over and
takes a look at it. He studies it for a while and then suddenly - bing....
a little light bulb goes on above his head? Everybody in the house sighs and
knows it's in everyone's best interest to get out of there - quick.
In this experiment, we'll make a fluorescent light bulb 'go on' - literally.
And no evacuation will be called for...
- Take the comb and light bulb into a dark closet.
- Take the comb and rub it thoroughly through your hair. If you don't have any
hair, a wool shirt or sweater will work fine.
- Now hold the comb to the metal end of the light bulb while carefully watching the
filament in the bulb.
Pretty cool, huh? When you rub the comb through your hair, the friction between
your hair and the comb actually causes electrons to travel from your hair to the
comb. Your body (hair) becomes positively charged (because it has more protons
than electrons) while the comb becomes negatively charged (it gained electrons from
your hair) . The comb, in effect, becomes charged. When you touch the
comb to the end of the light bulb, the charged comb discharges into the light bulb
causing the bulb to emit small pulses of light.
Parent's Note . Sometimes, a large number of atoms in an object
gain or lose electrons. When such a gain or loss happens, the entire object takes
on an electric charge (then they're called ions). The term static electricity describes
situations where objects carry electric charge.
Static electricity occurs, for example, when you rub a balloon on your shirt. The
friction between the cloth and the balloon causes electrons to transfer from your
shirt to the balloon. The shirt then has an overall positive charge because it has
more protons than electrons. The balloon takes on a negative charge because it has
extra electrons. The balloon will then stick to the shirt or to another surface,
such as a wall.
Static electricity has many uses in homes, businesses, and industries. For example,
the copying machines found in most offices are electrostatic copiers. They make
duplicates of printed or written material by attracting negatively charged particles
of toner (powdered ink) to positively charged paper. Static electricity is also
used in air cleaners called electrostatic precipitators. These devices put a positive
electric charge on particles of dust, smoke, bacteria, or pollen in the air. Negatively
charged collector plates attract the positive particles out of the air.