Gertsch Group

Institute of Biochemistry and Molecular Medicine, University of Bern, Switzerland

Farewell to Edison

Farewell to Edison
Jurg Gertsch - Mon Oct 19, 2009 @ 04:49PM
Comments: 0

Science education is important but getting more difficult because of the increasing black box mentality in our society. If you are for example looking into a burning light bulb, the beautiful incadescent one that is now about to be banned worldwide, you really see a whole era of science. You look into the bulb and you see a piece of wire being heated up by electrical current until it starts to emit light. But if you look more closely you see the history of error and trial, the history of electricity and much more. Thomas Edison, the famous American inventor and scientist and his team wanted to chase electrons through a wire to have it glow up in order to emit light. They wanted electrical light for everybody. The final transition from stone age to modernity. At that time, they did not know that they see electrons moving in a conductor. The problem was that the wire got too hot and the bulb burned out quickly. So they discovered that evacuation of oxygen (vacuum) leads to increased efficiency. Kids learn that smashing a bulb is the contrary of an explosion called implosion. Edison knew that oxygen is important in the combustion process - that's the reason for the vacuum in the bulb. They tried out all sorts of wires, different metals. They started to learn about the properties of metals like copper, iron, nickel, and platinum. The electric current through these media was different. When a metal wire is connected across the two terminals of a direct current voltage source such as a battery, the source places an electric field across the conductor. The moment contact is made, the free electrons of the conductor are forced to drift toward the positive terminal under the influence of this field. The free electrons are therefore the current carrier in a typical solid conductor. In 1878, Edison applied the term filament to the element of glowing wire carrying the current, although the English inventor Joseph Swan had used the term prior to this. Edison tried all sorts of materials to improve the filament, teaching us how important it is to be inventive and persistent. Finally, when he tried carbonized bamboo fibres which lasted more than 1000 hours and thus much longer than any of the metals he had tried before (and was cheaper than platinum which would have been another good choice) - the modern light bulb was invented. It survived more than 100 years in different variations. I always thought that the light bulb was a good starting point to learn about electricity, electrons, atoms and photons and all the related subjects. The light bulb was the origin of the cathode discharge tube, radioactivity and beta-irradiation. Finally, thanks to Edisons`light bulb decades later the mass spectrometer based on ionizing molecules by adding or removing electrons or ions from molecules in vacuum was invented. Much of all this goes back to the incadescent light bulb. But with the divulgement of the energy efficient (cold) fluorescent gas discharge bulb things are different now. You don’t see anything if you look at it, all you see is a white box with a black box character. This does not really inspire a kids` brain. Did you know that the close to compulsory compact fluorescent lamps contain traces of mercury? Mercury is more neurotoxic than arsenic and far more neurotoxic than lead - so don't led implode a burning fluorescent lamp; either the black box character of the new lamp or the mercury vapours will cause problems - times are getting harder for science education.

Comments: 0

Post a Comment




powered by Doodlekit™ Free Website Maker