The light passed through the two pinholes and to a screen, where the two sources of light generated so-called interference fringes, alternating stripes of brightness and darkness. The bright stripes developed where both waves were at a peak or a trough, and dark stripes indicated where a peak of one wave coincided with a trough of another. Such an example of interference can be seen wherever two waves overlap in space and time, whether the waves exist in light, water or virtually anything else. Unfortunately for Young, many scientists still accepted Newton's theory. Eventually, scientists realized that Young was right.
Light travels in waves.
But in the early 1900s Albert Einstein confused the issue again. Just three more twists set the stage for the work at Weizmann. First, wave-particle duality applies to more than light. For instance, electrons act like particles in some cases and waves in others. Second, Niels Bohr posed the principle of complementarity, which states that something cannot act simultaneously like a particle and a wave.