Waves often travel from one point to another. However when two waves travel at same time a medium these waves passes through each other without getting disturbed. This is what we call superimposing each other. Superposition is the term that explains what happens when waves superimpose each other. When they are in phase they add up to form a larger wave and when they are out of phase they cancel out with each other. The young’s double slit experiment gives the hypothesis of interference by explaining superposition . .