SUPERCONDUCTIVITY
DEFINITION OF SUPERCONDUCTIVITY
Superconductivity is a phenomenon displayed by certain conductors that show no resistance to the flow of electric current. Conductors are materials in which the electron current goes through. There are 4 different kinds of conductors. Insulators, like glass or wood, have a very high resistance to electron current while semi-conductors, such as silicon, have a medium resistance. Conductors, like copper and other metals, have very low resistance, and superconductors, comprised of certain metals such as mercury and ceramics such as lanthanum-barium-copper-oxide, have no resistance. Resistance is an obstacle in the flow of electricity. Superconductors also have strong diamagnetism. In other words, they are repelled by magnetic fields. Due to these special characteristics of superconductors, no electrical energy is lost while flowing and since magnetic levitation above a superconductor is possible. This principle is employed in high-speed trains that travel at 483 km/h (300 mph) while levitating on a cushion of air.
MAKING OF THE SUPERCONDUCTOR
When superconductivity was first discovered, it was established that the compounds needed to be cooled to within several degrees Kelvin to absolute zero (zero Kelvin). The large amount of cooling was done by putting the compound in liquid helium. Helium, which is usually a gas, liquefies when its temperature drops to 4 K. Once the material had cooled to that temperature, it became a superconductor. However, using liquid helium to cool down material has been a problem. Liquid helium is very expensive, and the cooling equipment is very large. In the past, there was no economic incentive to replace ordinary conductors with superconductors because the cooling costs for superconductors were so high. Scientists have found two ways to overcome the cooling problems. The first is to find a way to cool the material using something less expensive and less bulky than liquid helium. The second way is to raise the temperatures that are necessary to cause superconductivity in the metals, or the critical temperatures. By combining materials into superconducting alloys, the temperature was raised slightly. By 1933, the critical temperature was at 10 K, and it wasn't until 1969 when the critical temperature was raised to 23 K and scientists tried, unsuccessfully, to raise it again. The...
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...ving atoms wandered out of the field, while the coldest atoms stayed in the center. Very few atoms could escape the coldness at the center, and the center is what became the new state of matter.
Future Developments
In the future, many scientists expect to have many new things due to superconductivity. Room temperature superconductivity would totally revolutionize the electrical power industry by making copper wires obsolete. Superconductivity would also improve transportation by changing the way trains, cars, and ships run. Magnetically levitated trains have the advantages of speed and quiet operation and the same magnetic levitation could be used with cars. Drivers would travel as fast as 150 mph on a highway and they would never have to worry about collisions. Ships propelled by superconducting motors would weigh less and would be more maneuverable. In conclusion, superconductivity will have a tremendous impact on our future, totally revolutionizing our way of life.
Works Cited
Seeber, Bernd Handbook of Applied Superconductivity University of Geneva
Switzerland, 1998
Kresin, Vladimir. and Wolf, Stuart Fundamentals of Superconductivity New York and
London Plunum Press., 1990
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