Figure 3-2Wave Travel (a) Electromagnetic radiation travels as waves. Thomas Young’s interference experiment shows that light of a single color passing through a barrier with two slits behaves as waves that create alternating light and dark patterns on a screen. (b) Water waves passing through two slits in a ripple tank create interference patterns. The water waves interfere with each other, creating constructive interference (crests) and destructive interference (troughs) throughout the right side of the tank and on the far right wall.