Sciencemadness Discussion Board

I'm baffled. Light from envelope glue???

Pumukli - 27-1-2017 at 04:11

Dear All,

It's been quite a while that I posted something (meaningful - some might think? -) but a few days ago I noticed something that baffles me since.

I was lazily opening a regular local (thin, white paper, with self-sticky edge) mail envelope which was surely closed about 4-5 months ago. I did not used a knife or a sophisticated "envelope opener" but tried to open it by de-attaching the self-adhesive "ear" of the envelope. While I was doing this I was in a half-shaded room which was only faintly lit and was talking to people so was not really concentrating on what I was doing with the envelope.

Now comes the fun part: I noticed from the corner of my eye that the separating self-adhesive layers EMITTED a very noticeable blue light!!! I was mesmerized and before I could stop my fingers I opened the envelope all the way up while I was watching the separation zone GLOWING in blue!
I cursed myself afterwards because I should had recorded the light with my cam to share with you, but the whole thing happened so quickly and out of blue that I was not prepared mentally. :-)

Of course I tried imediately re-attaching the self-adhesive layers and repeated the opening process but this time there was no light phenomenon at all. :-(

Anyway, I never encountered anything like this before, although I'm not a kid.

My questions are obvious: what was this? Sort of triboluminescence? How could I repeat it? Has anyone of the readers of this report seen something similar?

EDIT: Please, mods, move this post from the equipment acquisition thread to Beginnings! Sorry!

[Edited on 27-1-2017 by Pumukli]

Tdep - 27-1-2017 at 04:59

Why yes, what a nice discovery to make, you are not going crazy, it is triboluminescence. https://youtu.be/54R6q2_-4Yo

Marvin - 27-1-2017 at 05:01

This is known and I believe that by pulling apart the sides you are separating charges. The glow may be from ionised air.

Sulaiman - 27-1-2017 at 06:03

not just light, x-rays too ! https://www.newscientist.com/article/dn15016-humble-sticky-t...

EDIT : Original reference : http://www.nature.com/nature/journal/v455/n7216/full/nature0...
YouTube https://www.youtube.com/results?search_query=scotch+tape+x+r...

[Edited on 27-1-2017 by Sulaiman]

Morgan - 27-1-2017 at 14:11

"The triboelectric effect (the prefix tribo- comes from the Greek τρίβω for “rubbing” or “friction”) results in the creation of a charge difference between two surfaces: one becomes positive and the other negative. The difference in charge is neutralised when a spark jumps between the two surfaces."

"Opening “self-stick” envelopes quite often results in a noticeable triboelectric effect, as I discovered when opening this week’s copy of The Economist."
http://wordpress.mrreid.org/2011/06/09/triboelectric-envelop...

Morgan - 29-1-2017 at 07:29

It helps to go full screen to see it better.
Blue Lightning Envelope Effect
https://www.youtube.com/watch?v=2beDZY9XGGE

Maybe of interest
https://www.youtube.com/watch?v=JywjBAxxJHE

[Edited on 29-1-2017 by Morgan]

Chlorine - 29-1-2017 at 16:05

It's basically just a static discharge, same thing happens when duck tape is pulled apart or pop rocks are crushed.

j_sum1 - 29-1-2017 at 16:17

Quote: Originally posted by Chlorine  
It's basically just a static discharge, same thing happens when duck tape is pulled apart or pop rocks are crushed.

No. I don't think so. Triboluminescence is a real phenomenon.
http://recipes.howstuffworks.com/question505.htm