Glowing lifesavers and Masking tape - why does it happen?

When we were kids, we would take Wint-O-Green Lifesavers (at least I think it was Wint-O-Green... may have been Spearmint or Peppermint) and go into a dark room. When we would bite down, with our mouths open, we could clearly see sparks and flashes as the candy broke up. And the same thing with masking tape. We'd take it into the dark room, and pull a strip of tape off of the roll, quickly and firmly, and we'd see a bright glow along the interface where the tape pulled-away from the surface of the roll.


What causes this?

Glowing lifesavers and Masking tape - why does it happen?
Hi zeebya, I happen to know the phenomena you speak about. The light from the Life Savers is called triboluminescence. Basically, the crystalline structure in methyl salicylate (wintergreen oil flavour) flouresces when struck by ultraviolet light; the UV is in turn emitted by sugar crystals under the stress of the crushing force of your jaw.





I saw an article , at least 20 years ago, in Scientific American about triboluminescence. They also disussed the Scotch tape effect. I remember being intrigued by the fact the tape gets much thinner at the point where it's being pulled off -- it's under immense tension.
Reply:Hi. The life-saver uses a dye that glows when subjected to electricity. Biting the life-saver produces a small electric charge. I've never seen the masking tape trick (I'll try it) but I would guess that was static electricity discharging at the edge.