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.
