The Photon: Slit experiments: Cancelling each other out

The photon is one of the most enigmatic objects in the Universe. In the late nineteenth century it seemed clear that light was an electromagnetic wave. But today scientists accept that light can behave both as a wave and a particle, the latter known as the photon. Understanding light in terms of photons has enabled the development of some of the most important technology of the last fifty years. With Frank Close, Professor Emeritus of Physics at the University of Oxford; Wendy Flavell, Professor of Surface Physics at the University of Manchester; and Susan Cartwright, Senior Lecturer in Physics and Astronomy at the University of Sheffield.