Superconductors are one of the trending topics in the science world at the moment. They are materials that conduct electricity with no resistance, which means that when it carries a current, it doesn't lose any energy. Also no magnetic field can pass through a superconductor. These properties have led to their applications in many fields such as medicine (for MRI machines), Power utilities, military and even transportation (there is a train with a superconductor base that hovers above the tracks, which means that there is little to no friction!).
The first discovery of a superconductive material was in 1911 by H.K. Onnes. He was also the first to liquefy helium and reach temperatures as low as 1.7 kelvin ( -271.45 celsius). He first discovered superconductivity by cooling a wire made of mercury to a temperature of 269 Celsius (4K) and found that the electrical resistance suddenly disappeared. He also found that if a strong magnetic field is applied, the superconductivity is gone.
The best theory we have currently of how superconductors work is the BCS theory, developed by John Bardeen, Leon Cooper and Robert Schrieffer. Normally, when we pass a current through a material, the electrons flow through. However, resistance is caused when the impurities, defects and vibrations of the materials crystal lattice (caused by thermal or kinetic energy) deflecting the electrons. However, when there are low temperatures, the vibrations significantly decrease and the electrons inside the material join to make Cooper pairs and can move more freely without being scattered.
The inability of magnetic fields to pass through a superconductor is known as the Meissner Effect, discovered by Karl Meissner and Robert Ochsenfeld. This happens when we stand a superconductor in a magnetic field. The magnetic field induces an electric current. This electric current flowing through the surface of the superconductor creates its own magnetic field. This makes a force that exactly cancels the original field trying to get inside the superconductor and repels the magnetic field outside. This explains how you can make a superconductor levitate in a magnetic field.
The first discovery of a superconductive material was in 1911 by H.K. Onnes. He was also the first to liquefy helium and reach temperatures as low as 1.7 kelvin ( -271.45 celsius). He first discovered superconductivity by cooling a wire made of mercury to a temperature of 269 Celsius (4K) and found that the electrical resistance suddenly disappeared. He also found that if a strong magnetic field is applied, the superconductivity is gone.
The best theory we have currently of how superconductors work is the BCS theory, developed by John Bardeen, Leon Cooper and Robert Schrieffer. Normally, when we pass a current through a material, the electrons flow through. However, resistance is caused when the impurities, defects and vibrations of the materials crystal lattice (caused by thermal or kinetic energy) deflecting the electrons. However, when there are low temperatures, the vibrations significantly decrease and the electrons inside the material join to make Cooper pairs and can move more freely without being scattered.
The inability of magnetic fields to pass through a superconductor is known as the Meissner Effect, discovered by Karl Meissner and Robert Ochsenfeld. This happens when we stand a superconductor in a magnetic field. The magnetic field induces an electric current. This electric current flowing through the surface of the superconductor creates its own magnetic field. This makes a force that exactly cancels the original field trying to get inside the superconductor and repels the magnetic field outside. This explains how you can make a superconductor levitate in a magnetic field.
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