When you peel off a strip of Scotch tape, you're holding a tiny particle accelerator. Think of this during the upcoming holiday season. As you wrap present after present, you're simultaneously creating an electric field powerful enough to accelerate any free electrons hovering around. Under the right conditions, this can coax the electrons into spewing out X-rays. The good news: As long as you aren't playing Santa in a vacuum, you don't need to worry about the radiation exposure—the electrons will bump into air molecules long before they get a chance to start emitting any X-rays. Science News explains:
Peeling tape separates positive and negative charges, creating an electric field. The field jump-starts free electrons in the neighborhood, accelerating them fast enough to emit X-ray photons. This bremsstrahlung radiation is like that created in the bellies of particle accelerators as they whip charged particles around near the speed of light.
Other materials can generate X-rays using the same principle, says Putterman. He imagines that soldiers and medical workers in the field could use a hand crank to peel off adhesives and create X-rays. The light is powerful enough to image a human finger.
But it's still a mystery how tape could separate enough charge to create a strong electric field.
Thanks to RebNachum for Submitterating this one!