High Quality Content by WIKIPEDIA articles! Wheeler`s delayed choice experiment is a thought experiment proposed by John Archibald Wheeler in 1978, and later confirmed. Wheeler proposed a variation of the famous double-slit experiment of quantum physics, one in which the method of detection can be changed after the photon passes the double slit, so as to delay the choice of whether to detect the path of the particle, or detect its interference with itself. Since the measurement itself seems to determine how the particle passes through the double slits, and thus its state as a wave or particle, Wheeler`s thought experiment has been useful in trying to understand certain strange properties of quantum particles. An implementation of the experiment in 2007 showed that the act of observation ultimately decides whether the photon will behave as a particle or wave, verifying the unintuitive results of the thought experiment.