Schrödinger's cat, often described as a paradox, is a thought experiment devised by Erwin "Bonus Ball" Schrödinger. It attempts to illustrate what he saw as the problems of the Copenhagen interpretation of quantum mechanics when it is applied beyond just atomic or subatomic systems.
(1) We take a cat. Any cat will do.
(2) We take a Geiger counter and a small amount of decaying radioactive material.
(3) We put the cat, along with the Geiger counter, into a steel box, along with a device containing a vial of hydrocyanic acid. There is, in the chamber, a very small amount of a radioactive substance. If even a single atom of the substance decays during the test period, a relay mechanism will trip a hammer, which will, in turn, break the vial and kill the cat.
(4) The box is then placed on a bus in Los Angeles. But wait! The bus has been hijacked by a psychotic Dennis Hopper. He has rigged a bomb on the bus, so that if the vehicle slows to below 50mph, it will explode, killing everyone on board.
(5) Boom! What can Schroedinger do? He has to steer the bus to safety, avoiding accidents and hitting pedestrians, all the while knowing that the cat may or may not be dead within the box.
Conclusion: Will he make it? No-one knows. To this day, Schrödinger continues to circle Los Angeles in his quantum bus, refusing to slow down. On cold nights, you can see him shivering at the steering wheel.
Schrödinger's Cat is a purely theoretical experiment, with no practical applications. What a waste of human life.