Schrödinger's cat
In 1953, Schrödinger came up with a thought experiment that expanded the limits of basics understanding of classical physics at the time. The purpose of this Gedankenexperiment is to consider the consequences of a principal in question, and if it's possible to even perform it. Schrödinger's experiment is one of the more famous thought experiments along with Maxwell's Demon, and they have both led to massive gains in the physics and scientific communities. This is how Schrödinger's thought experiment works:A cat is locked in a box along with a radioactive atom that is connected to a vial of poison. When the atom decays it causes the vial to be opened which kills the cat. With the box sealed, it is unknown whether or not the atom is decayed, which means it could be both in the decayed state and the non-decayed state at the same time. Therefore, the cat is both DEAD and ALIVE at the same time....
(http://www.cartoonsidrew.com)
Surely this can't be possible, but yet physicists have used this method and way of thinking to find amazing results much like Jonathan Friedman of the State University of New York (SUNY) in Stony Brook. They demonstrated how a superconducting device would work in a quantum superposition of two states (current flow in different directions).