When you peel sticky tape in the dark, you can see tiny sparks. This is a process called Triboluminescence. The same thing happens when you smash sugar crystals (for instance, by chewing). Materials scientists lack a consensus but the current theory is that after the bonds are broken, electrons hurry back to their atom of interest. Once they get back, the energy they had while zooming is released as a photon, which can be in the X-ray region of the spectrum!
AP: a machine peeled ordinary Scotch tape off a roll in a vacuum chamber at about 1.2 inches per second. Rapid pulses of X-rays, each about a billionth of a second long, emerged from very close to where the tape was coming off the roll.
That's where electrons jumped from the roll to the sticky underside of the tape that was being pulled away, a journey of about two-thousandths of an inch, Escobar said. When those electrons struck the sticky side they slowed down, and that slowing made them emit X-rays.
Reuters: Carlos Camara of University of California, Los Angeles and colleagues used a motorized peeling machine to unwind a roll of tape in a vacuum.
They generated enough X-rays to show the bones inside their fingers.
"The tape has to be in the vacuum. Your hand can be outside," Camara said in a telephone interview on Thursday.
"If you unroll the tape on your office desk in ambient conditions you only get visible light. You don't get X-rays," he added. This is because gases in the air slow down the electrons that produce the X-rays.
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