Superconductors are materials that conduct electricity without resistance. As a result, they can conduct electricity indefinitely without losing energy unlike common conductors like copper and steel.
In 1911, Dutch physicist Heike Kamerlingh Onnes of Leiden University first observed superconductivity in mercury. When he cooled it to the temperature of liquid helium, which is 4 degrees Kelvin its resistance suddenly disappeared. The Kelvin scale represents an absolute scale of temperature.
Heike Onnes also discovered that a superconducting material can be returned to normal, non-superconducting state, in two ways. This can be done either by passing a sufficiently large current through it or by applying a sufficiently strong magnetic field. In 1913, Onnes was awarded the Nobel Prize in physics for his research in this area.
The discovery of superconductors has made drastic improvements in the medical field. With the advent of MRI machines, exploratory surgeries are no longer as necessary as it once was.
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