FAIL. http://acid3.acidtests.org/

Popcorn panic due to the microwave detecting an invalid butter measurement.

If sunlight is replaced with a light source that is capable of producing just one photon at a time, and the screen is sensitive enough to detect a single photon, This experiment can, in theory, be performed one photon at a time -- with identical results. If either slit is covered, the individual photons hitting the screen, over time, create a pattern with a single peak. But if both slits are left open, the pattern of photons hitting the screen, over time, again becomes a series of light and dark fringes. This result seems to both confirm and contradict the wave theory. On the one hand, the interference pattern confirms that light still behaves much like a wave, even though we send it one particle at a time. On the other hand, each time a photon with a certain energy is emitted, the screen detects a photon with the same energy. Under the Copenhagen Interpretation of quantum theory, an individual photon is seen as passing through both slits at once, and interfering with itself, producing the interference pattern. A remarkable refinement of the double-slit experiment consists of putting a detector at each of the two slits, to determine which slit the photon passes through on its way to the screen (If the photon or electron passes through only one slit - which it must do, as, by definition, a photon or an electron is a quanta, or "packet" of energy which cannot be subdivided - then logically it cannot interfere with itself and produce an interference pattern). When the experiment is arranged in this way, the fringes disappear. The Copenhagen interpretation posits the existence of probability waves which describe the likelihood of finding the particle at a given location. Until the particle is detected at any location along this probability wave, it effectively exists at every point. Thus, when the particle could be passing through either of the two slits, it will actually pass through both, and so an interference pattern results. But if the particle is detected at one of the two slits, then it can no longer be passing through both - it must exist at one or the other, and so no interference pattern appears. The many worlds interpretation states that the particle not only goes through both slits but that it is detected at every possible final location as well -- but in different, mutually unobservable worlds. This is similar to the path integral formulation of quantum mechanics provided by Richard Feynman (although Feynman stresses that this is merely a mathematical description, not an attempt to describe some "real" process that we cannot see), in which a particle such as a photon takes every possible path through space-time to get from point A to point B. In the double-slit experiment, point A might be the emitter, and point B the screen upon which the interference pattern appears, and a particle takes every possible path - through both slits at once - to get from A to B. When a detector is placed at one of the slits, the situation changes, and we now have a different point B at the detector, and a new path between the detector and the screen - upon which the interference pattern no longer appears).