scotchYeah, yeah, I know, this is old news, but I finally got around to reading the articles about the fact that Scotch tape emits x-rays. I’ve known for a while that when you stick scotch tape to something and then peel it off, the scotch tape gets charged (negatively for those who care). This is a great way to make a cheap electroscope for your classroom (or just anytime you want to find out the charge on something). Just stick Scotch tape to a table, peel it off, and then hold it near some Charged Object. If the tape is repelled, then the Charged Object is negatively charged (since like charges repel). Try it, it’s cool.

So, anyway, when you peel the tape off the table, it gets negatively charged by ripping electrons off the table. This is, in effect, a current — electrons are flowing from the table to the tape. If you peel tape off a table in a dark room you’ll see light. From what I gather, as the electrons slow down when they hit the tape, they give off radiation (this would be Bremsstrahlung or “Braking” radiation). When you do this in a dark room, you’re seeing that radiation as visible light.

The new research shows that if you do it in a vacuum, instead of these visible photons (which are just a form of electromagnetic radiation with a relatively low energy), you get x-rays (electromagnetic radiation with high energy). The x-rays were strong enough to take a picture of one of the researchers’ finger.

The NY Times article on this says:

All of the experiments were conducted with Scotch tape, manufactured by 3M. The details of what is occurring on the molecular scale are not known, the scientists said, in part because the Scotch adhesive remains a trade secret.

Other brands of clear adhesive tapes also gave off X-rays, but with a different spectrum of energies. Duct tape did not produce any X-rays, Dr. Putterman said. Masking tape has not been tested.