Whether you learned that light was a particle or a wave in high school physics, you likely inferred that only physicists could ultimately weigh in on the subject. Technically true, I suppose, but there are a number of artists demonstrating quite deftly that light is a medium, too.
Artist Darren Pearson is one such person. Pearson paints with light directly, rather than using paints to reflect and absorb certain wavelengths. This direct method of expressing images with light is done with a flashlight and a camera capable of a long exposure. If you've ever seen a night image of cars on a highway where their headlights blur together into a snake-like line, then you have seen this concept illustrated. Pearson sets up at dusk facing the camera with flashlight in hand. He opens the camera shutter remotely, turns on his light and begins to draw in the air. To a passing observer, he must look like a crazy man, flailing wildly about for no one in particular. But when the shutter finally closes, he is left with this:
And if that isn't impressive enough, he recently stitched together over 700 of his light paintings to create a stop-motion video of a skateboarding skeleton. It took over a year to create: