1. From water waves to light waves

2. So far, we have learned that the particle theory and the wave theory of light both predict the observed phenomena's of light. However, as we saw, neither theory could account for all observed phenomenons. So, for more than 100 years, both remained in conflict until Thomas Youngs double slit experiment. What was not known during Newtons and Huygens time was how small the wavelength of light really was. However, during Youngs time this was better understood. As such, Young used this knowledge to construct a better experimental apparatus that could show that light did in fact behave like a wave.

3. Conclusion: Light is a Wave!

4. Recall for water waves: Minima (Dark Band) However, this expression accounts only for destructive interference; what about constructive interference?

5. Constructive interference occurs when the incoming waves have a path difference of Thus, Maxima (Light Band)