|Thomas Edison's first successful light bulb model, used in public demonstration at Menlo Park, December 1879 |
Strip off a little less than an inch of the insulation from the other end and bend the wire into a hook.
Drill two holes in the top of a jar's lid. Push the wires through the holes. hooked ends first and glue them into place with a glue gun.
Straighten out a paper clip and then curl it around a nail to make a coil. Rest the coiled clip in the hooks of wire to form a filament.
Light a tea-light candle and drop it into the jar and put the top on tightly. After a few seconds the candle will run out of oxygen and go out, leaving a vacuum of sorts.
In a dark room, attach the metal clips to the terminal of a 6-volt lantern battery. Wait a few seconds, and your bulb should glow.
The Science Behind It?
The paper clip is made out of steel, which conducts electricity much more poorly than the metal in the electric wire. The resistance is so high and produces so much heat that the paperclip begins to glow. The candle consumed the oxygen inside the jar that would otherwise react with the hot filament and make it burn out more quickly.
- The Story Of Thomas Alva Edison, Margaret Davidson, On October 19, 1879 Thomas Edison turned electricity into light with the invention of the electric light bulb. Thomas Edison also invented the phonograph and an early form of motion pictures. This is the amazing story of his life---and of his inventions that changed the world.
- Science Rocks!