In 2008, scientists found that they could generate enough X-ray radiation to take an image of a researchers finger simply by unrolling a roll of adhesive tape. As the video above shows, the trick is to unroll the tape in a vacuum. According to Scientific American:
The reason, says Camara: electrons (negatively charged atomic particles) leap from a surface (peeling off of glass or aluminum works, too) to the adhesive side of a freshly yanked strip of tape, traveling so fast that they give off radiation, or energy, when they slam into it.In a regular atmosphere, the electrons still give off radiation, but because the air molecules slow them down, they appear in the visible spectrum.
We tested this in a dark room (so dark that you can't see) using both adhesive tape and duct tape. Peeling the tape off quickly gave off a bright blue flash, but peeling it slowly produced a steady blue line where the tape was unrolling from the roll. With adhesive tape, at least, we could create the effect again and again with the same piece of tape. It's called called triboluminescence-- the same process that creates sparks when you bite into Wintergreen Life Savers.
Our little camera wasn't sensitive enough to pick up the blue flash, but here's a YouTube video made by someone with better equipment: