Can someone explain Schrodinger's cat paradox to me in a very, very simple way?

This revolves round a principle of quantum theory called "superposition", which basically claims that if you don't know what the state of any object is, then - as long as you don't look to check - it is actually in all possible states simultaneously. "echotolosa" therefore is simultaneously male, female and hermaphrodite according to superposition, until you meet me and see I'm female ! It's the checking that limits it to a single possibilty.

Erwin Schrodinger proposed a theoretical experiment in which a cat was put in a steel box along with a vial of hydrocyanic acid along with a tiny amount of a radioactive substance. If just one atom of this decayed during the test period, it would trigger a sequence in which a hammer would break the vial and kill the cat. As long as the box stayed closed, you wouldn't know whether this had happened or not, so according to quantum law and the superposition of states, the cat is both alive and dead at one and the same time. It's only when you take a measurement, ie look in the box, that the superposition ceases to be and the cat is either alive or dead. The paradox is that observation (=measurement) affects the outcome, so the outcome doesn't exist until the measurement is made.

Apparently superposition does occur on the subatomic level, ie as regards electrons, and this could have implications about reality on the observable level, when dealing with cats rather than electrons.

http://whatis.techtarget.com/definition/0,,sid9_gci341236,00.html

Schrödinger's cat is a thought experiment about quantum physics. It was proposed by Erwin Schrödinger.

A cat is placed in a room that is shielded from the environment. A Geiger counter and a little bit of a radioactive element are in the room. Within some time, say one hour, one of the atoms of the radioactive element may decay, or it may not. The Geiger counter can of course measure that. If it does measure the decay, it will release some poisonous gas, which will kill the cat.

The question now is: at the end of the hour, is the cat alive or dead?

Schrödinger's interpretation is that as long as the door is closed, the cat is both dead and alive in dual superposed quantum states. When the door is opened, the quantum states are made known and the cat is observed to be either alive or dead.

The problem exists in that by opening the room, the person is interfering with the experiment. The person and the experiment have to be described with reference to each other. By merely looking at the experiment the person has influenced the experiment.

http://simple.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat

Take one ordinary cat, one large box, a particle detector, a radiation source, a bottle of cyanide gas. Hook up the detector so that if it detects a particle from the radiation source, it will open the cyanide gas. Set it up inside the box in such a way that there will be a 50% probability of a particle being detected from the radiation source within a five minute period. Add the cat to the box.

Theory says that the cat will enter a quantum state where it is 50% alive and 50% dead until the experimenter looks inside the box. However, reality teaches us that the severely pissed off cat WILL escape the box well before the 5 minutes are up, attack the experimenter and depart just in time for the severely lacerated experimenter to watch the hammer descend on the cyanide bottle one inch from his nose.

Video explanation: