Schrödinger’s Box is a thought experiment developed by Edwin Schrödinger to explain the fundamental idea behind quantum mechanics. The thought experiment is as follows: You are given a box that contains a cat. The instant you open the box the cat is killed. The question is, is the cat inside the box with the lid closed alive or dead? We don't know if the cat is alive or dead when inside the box. This idea demonstrates the fundamental nature of quantum mechanics. Until a particle is measured we do not know where it is, how fast it’s moving, what its mass is, or how much energy it has. Quantum mechanics deals in probabilities. The is a probability of 25% that the particle will be found here, a probability of 37% that it will be found over there, etc. When we measure a particle, we then know something about it. If we repeat an experiment a large number of times, the results will not be the same every time. The results will begin to distribute themselves like the theoretical probabilities. For example, if we repeat an experiment 10 000 times approximately2 500 times the experiment will yield result A while 3 700 times gives result B and so forth. What we know depends on what information we are trying to measure. I know that sounds obvious but some quantities in physics interact with each other. Heisenberg formulated this idea and it became know as the Heisenberg Uncertainty Principle (HUP). If we know one quantity with absolute precision, we cannot know its companion quantty with any precision. For example, we cannot know both the mass and the velocity of a particle with absolute precision. The HUP is derived from the mathematical formulation of quantum mechanics.

Timbugtoo is close, but implies that it is the act of opening the box that kills the cat. Actually, there is a device inside the box which will release a poisonous gas upon the first release of a decay particle from some radioactive material. It is not possible to know precisely when the decay will occur, only the probablility by a given time. Because the wave function in quantum mechanics seems to exist in two states simultaneously, taking one or the other only upon observation, so long as the box is closed, the decay has and has not occured and the cat can be both dead and alive at the same time. The act of opening the box and observing the cat collapses the wave functions and causes them to assume a single state. It is a thought experiment that illustrates some of the oddities of the quantum world.