Thomas Edison tried many filament designs in his quest to perfect a long-burning "incandescent bulb." You can imitate his experiments by running two insulated copper wires vertically through a cork that fits tightly into a wide-mouth clear jar letting the bottom end dangle about two inches into the jar. Strip the plastic coating off these short ends and bend the wire into a "J"-shape. Experiment with laying different filament designs across the hook using different filament materials, shapes and single strand vs. multi-strand filaments. Try iron wire, aluminum wire, carbon wire, charred cotton thread and bamboo, for example. Place a lighted tea light candle in the bottom of the jar and seal with the cork. When the candle flame goes out indicating that all oxygen is used up creating a vacuum, attach the long end of the copper wire to a 6-volt battery and measure the longevity of the bulb life.
Edison was the first to successfully create a machine that could both record sound and play it back. This started a revolution in the way people listen to music, beginning with his phonograph and evolving into the MP3 players that are common today. His design used a diaphragm to help conduct the sound. Try your own sound experiments by constructing a diaphragm out of tin foil or rubber balloon stretched tightly and secured over the open ends of a tin can or funnel. Tape a needle to the diaphragm so that it hangs off the edge. Place an old vinyl record on a turntable and turn it on. Lightly touch the needle to the first groove in the record and listen for the music. Repeat the experiment with different diaphragm designs to compare the loudness and clarity of playback.
In 1892, the U.S. Patent Office issued Edison a patent for the first two-way telegraph. With a 9-volt battery, 9-volt snap connectors, two push switches, two piezo buzzers and hookup wire available from an electronics store, you can rig up your own two-way telegraph to send messages to your friends. Connect the push button switches to the buzzers on the opposite end. Connect the push button and buzzer on one end to the negative battery terminal and the other pair to the positive battery terminal. Tap the switch on one end to activate the opposite buzzer. Recruit a friend and give her a copy of Morse code. Try sending simple messages back and forth for one another to record and decode.
Edison and the staff of his Menlo Park lab pioneered film as a form of mass media with the development of the kinetoscope and vitascope. The latter projected the first motion pictures in New York City in 1896. Make your own motion picture using a salad spinner and series of successive movement images that will appear animated when viewed in rapid sequence. Cover two slits in the salad bowl with black tape and leave the third uncovered. Continue taping in this pattern around the circumference of the bowl. Glue or tape the images in order around the inner wall of the bowl. Invert the spinner lid and secure the bowl on the rotating disk. Look through the side slits as you rapidly rotate the spinner handle to view your animation.
Edison's inventions ran off of direct current, or DC electricity, as opposed to alternating current or AC. He was convinced that AC was dangerous and put a great deal of effort into proving his claim and promoting the adoption of DC as the electricity standard for the new industry, a battle he lost as AC inventions became more popular. With copper wire and a D battery, you can make a simple direct current motor. Make a tight coil of enamel-coated 20- to 24-gauge magnet wire looping the wire 25 to 30 times and wrapping the free end around the coil opposite one another to secure it. Leave an inch or two of wire sticking out perpendicular to the loop on each and remove the top half of the coating. Wrap two pieces of bare copper or brass wire around a pencil a couple of times, letting the free ends hang down two inches on both sides. Lay the battery holder on its side and insert the supports on each end. Insert the coil into the rings and lay the magnet just under it on the holder adjusting the supports to make sure the coil can spin freely. Place the battery in the holder to watch your motor spin.