In 1908 Kamerlingh Onnes a Dutch physicist had one goal only; to achieve the lowest temperature ever recorded but his work paved the way for a completely new branch of science that is still keeping researchers busy today.
To achieve his goal he cooled and compressed Helium gas using liquid Hydrogen, before suddenly expanding it, hence cooling the Helium further (similar to how a conventional refrigerator works) until it liquefied. Once he had accomplished a temperature of 1 Kelvin (just one degree above absolute zero) he opened up the way for the study of matter at extreme temperatures. The same day, he observed that helium stops boiling two degrees above absolute zero. He did not know it, but he was the first person to observe Helium superfluidity.
He used his new way of cooling materials to develop an understanding of how they may behave and he and his fellow scientists were astonished by their discoveries. At very low temperatures, the electric and magnetic properties of some materials, especially metals, radically change. These materials become known as superconductors. They have no electrical resistance and display no magnetic fields. The many free electrons of the material merge into a quantum wave which spreads across very large distances.
Today, superconductivity is an extremely active field of research which includes creating new superconductors, and finding more new applications. One of the most amazing features of superconductivity is the spectacular feats of levitation. The fastest train in the world in Japan does not touch the tracks and uses superconductors. The train actually levitates a few inches above the tracks using strong magnetic fields created by superconducting coils carried and cooled on board. There are also many other uses including in electricals, medical applications, in particle accelerators, in astrophysics with the use of bolometers and in ultrasensitive magnetic detectors called SQUIDs
However, their use in everyday life is restricted by the very low temperatures that need to be achieved and maintained and the cost of this.
Research now is focused on the possibility of supersolidity in around 10 universities around the world and the uses of these materials are still unknown.