Two Slit (Double Slit Experiment) Rose

Thomas Young's classic double-slit experiment. Waves hit a screen with two gaps. The gaps act as new wave sources, creating two sets of circular waves radiating outwards. These two new waves create an interference pattern as they superimpose on each other. The waves sum together producing higher peaks and deeper troughs at some points (constructive interference), whilst cancelling each other out at other points (destructive interference).