Answer: Scotch Tape
In 2008, a group of researchers stated that UCLA came across evidence of experiments done in the 1
It turns out that when you unroll a roll of cellophane tape, you create a tiny interaction between the bonds of the adhesive and the tape. Much like chewing Wint-O-Green mints in a dark closet, you can quickly unroll a roll of cellophane tape to create a faint blue glow-a phenomenon known as triboluminescence. The energy generation of tape does not end there, however. If you take that same cellophane tape, capable of triboluminescence under normal atmospheric conditions and quickly unroll it in a vacuum, it also generates a surprising volume of X-ray radiation. How much radiation? The researchers were able to use small squares of dental film to create primitive X-ray images of their fingertips simply by resting their fingers at the experiment's enclosure.
Research is continuing on the discovery. One potential real-world application of the technology would be the deployment of x-ray devices in locations where the bulk and nuclear content of a regular x-ray machine would be prohibitive.