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Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
Hi guys, Yesterday I received a letter and while opening it in a dark room I noticed that the glue emits blue light when the glued pieces are pulled apart. Do you somebody knows whether this has some purpose or it is just coincidental by-product? And also what principle of light generation is this?
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
I had forgot about this, but also noticed it when opening the mail in the dark if i dont get to turn on the light first, thanks for bringing it up and for the solution :)
At first I thought it was a safety thing so you could see if a letter had been opened, but since it can be done multiply times I dropped that again.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
When you strike two milk quartz beach pebbles together in the dark, they glow momentarily at the points of impact. It does seem to work best when you strike glancing 'friction' blows, but thought the materials had to be of different electronegative materials to produce triboelectricity. Is this glowing after percussion perhaps due of the piezoelectric effect, I wonder, or some other effect?
Registered Member #1630
Joined: Sat Aug 09 2008, 11:36AM
Location: Seoul Korea
Posts: 115
It is triboelectric/triboluminescent effect with the glue, same situation with the tape. Acetate overhead sheets are really an amazing Triboluminescent material!! fractolumienscent/Piezoelectric effect is with quartz or crystalline materials
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Strange light emission during opening of a letter
Et least I learned a new word - Triboluminescence
