http://www.youtube.com/watch?v=DfPeprQ7oGc&feature=player_embedded
Ok - The double Slit Experiment. Watch the video above and then read the following:
The theory seeks to explain how an entity such as a photon or an electron, could 'travel as a wave but arrive as a particle'. According to the theory, what is passing through the experiment is not a material wave at all, but is a 'probability wave'. In other words, the particle does not have a definite location, but has a probability of being here or there, or somewhere else entirely. Some locations will be more probable than others, such as the light areas in the interference pattern for example, and some will be less probable, such as in the dark areas. In this theory, an electron that is not being observed does not exist as a particle at all, but has a wave-like property covering the areas of probability where it could be found. Once the electron is observed, the wave function collapses and the electron becomes a particle. This theory rather neatly explains the behaviour of the particles in the double slit experiment. When we are not looking at the particle, the probability wave, of even a single particle, is spread out and will pass through both slits at the same time and arrive at the detector as a wave showing an interference pattern. When we observe the electron by placing detectors at the slits, it is forced into revealing its location which causes the probability wave to collapse into a particle. If the theory is correct, its implications are staggering. What it suggests is that nothing is real until it has been observed, Nothing is real until it has been observed! This clearly needs thinking about. Are we really saying that in the 'real' world - outside of the laboratory - that until a thing has been observed it doesn't exist? This is precisely what the Copenhagen Interpretation is telling us about reality. This has caused some very well respected cosmologists (Stephen Hawking for one) to worry that this implies that there must actually be something (or someone) 'outside' the universe to look at the universe as a whole and collapse its overall wave function.
Ok - The double Slit Experiment. Watch the video above and then read the following:
The theory seeks to explain how an entity such as a photon or an electron, could 'travel as a wave but arrive as a particle'. According to the theory, what is passing through the experiment is not a material wave at all, but is a 'probability wave'. In other words, the particle does not have a definite location, but has a probability of being here or there, or somewhere else entirely. Some locations will be more probable than others, such as the light areas in the interference pattern for example, and some will be less probable, such as in the dark areas. In this theory, an electron that is not being observed does not exist as a particle at all, but has a wave-like property covering the areas of probability where it could be found. Once the electron is observed, the wave function collapses and the electron becomes a particle. This theory rather neatly explains the behaviour of the particles in the double slit experiment. When we are not looking at the particle, the probability wave, of even a single particle, is spread out and will pass through both slits at the same time and arrive at the detector as a wave showing an interference pattern. When we observe the electron by placing detectors at the slits, it is forced into revealing its location which causes the probability wave to collapse into a particle. If the theory is correct, its implications are staggering. What it suggests is that nothing is real until it has been observed, Nothing is real until it has been observed! This clearly needs thinking about. Are we really saying that in the 'real' world - outside of the laboratory - that until a thing has been observed it doesn't exist? This is precisely what the Copenhagen Interpretation is telling us about reality. This has caused some very well respected cosmologists (Stephen Hawking for one) to worry that this implies that there must actually be something (or someone) 'outside' the universe to look at the universe as a whole and collapse its overall wave function.
