Some of the more interesting answers when people were questioned what is light are light is an element, light is brightness and that’s a good question.  Apparently this question has been debated for centuries and Newton hypothesized that light was a stream of particles.  He proposed this in his book Opticks.  At the same time a Dutch physicist proposed that light was a wave and the battle raged on.

Somehow they gained access to a vault in London where they gained access to Thomas Young’s hand written notes.  They go on to shine light through two very narrow slits side by side and the viewers seem to see a bunch of dots when they look through the device.  However when they go to a pond and take two balls creating outgoing overlapping ripples, they demonstrate how the waves gets amplified and can also cancel each other out.  So different colors of light are from different wavelenghts from their meetup points, thus proving light is made of waves.

photo by John Liu