Superconductivity
It was known that resistance is proportional to temperature, and an experiment on very cold mercury found that by 4.2°K, its resistance was 0. This phenomenon was called superconductivity and was soon observed in some other metals.
It was known that resistance is proportional to temperature, and an experiment on very cold mercury found that by 4.2°K, its resistance was 0. This phenomenon was called superconductivity and was soon observed in some other metals.