Wednesday, March 19, 2008

A bright idea!

Charge up a light bulb

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 (a negatively charged subatomic particle. Electrons are found at varying distances from a atom's nucleus. They make up almost the entire volume of a atom but only account for a small part of the atom's mass.) 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.