The "Schrödinger's cat" experiment was created by Erwin Schrödinger in 1935 and demonstrates superposition in quantum theory. It proves that the conflict between what quantum theory tells us, where we know the nature and behaviour of matter, and what we observe to be true all depends on what we see with our eyes. This is due to the fact that we never know the actual truth of what the behaviour of the matter is until we see it with our own eyes.
The experiment consists in placing a living cat into a steel chamber that has a vial containing a very small amount of hydrocyanic acid inside. If the acid decays it causes a mechanism to release a hammer which will to break the vial and therefore kill the cat.
The observer, on the other hand, will never know if the acid has decayed and released the hammer and therefore won't be able to prove if the cat is dead or alive. Here the quantum law states that the cat is dead and alive at the same time, this is called superposition of states. Meaning that we only know for sure the behaviour and state of the cat once we open the chamber. Once we do so the superposition is lost as the cat then will either be alive or dead but not both. This can be called "observer's paradox" where there are no true results if observation isn't used.
by Clara N. 3ºY