Talk:Ute tribe

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[edit] Title

Why is "Tribe" capitalized?--Rockero 01:55, 26 April 2006 (UTC)

I changed it. — Omegatron 15:40, 25 November 2006 (UTC)

[edit] Comment on piezoelectricity

1) Piezoelectricity has been observed by the greeks, who noticed that a heated piece of quartz attracts ashes.

2) Triboluminescence is the physics effect that explains the light emitted by Utes rattles filled with quartz crystals rather than piezoelectricity. I changed the explaination in my french translation of the article[1]. Charele 14:16, 23 July 2006 (UTC) Charles@Hirlimann.net]]

Do you mean pyroelectricity? — Omegatron 04:52, 28 November 2006 (UTC)

• Triboluminescence is caused by electrical discharges from breaking crystal bonds, or cracks in the crystal.
• Piezoelectric flashes are caused by electrical discharges from deformation of the crystal and the production of large voltages, without breaking anything.

I know quartz is piezoelectric. I don't know if it also produces triboelectric flashes. I don't know which is causing the effect in this case, if not both, but people continue to change it without providing any references. Please provide an (authoritative) reference for the cause of the effect before changing it again. — Omegatron 22:46, 22 November 2006 (UTC)

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Moved from User:Deglr6328:

Why do you think the quartz rattles are triboluminescence? — Omegatron 22:40, 22 November 2006 (UTC)

Cuz its light created by charge asymmetry separation upon crystal fracture. I suppose VEEERY strictly speaking its "fractoluminescence" but nearly no one ever uses that term. Some materials are only piezoelectric, some are only triboluminescent, some are both and many are neither. [2] [3].--Deglr6328 22:48, 22 November 2006 (UTC)

And you were there to witness the crystals fracturing? Electrical discharges can be created by deforming piezoelectric materials without fracturing them, too. Talk:Ute_Tribe#Comment on piezoelectricity — Omegatron 08:32, 23 November 2006 (UTC)

wha? I don't know what you mean. Triboluminescence of SiO2 crystal fracture is well well known. you can buy a little kit from edmund scientific for like 5 bucks or something that includes a pair of quartz rocks that emit lots of light when rubbed against eachother. tribo=rubbing luminescence=light emitting. My first refrence link above discusses in detail the spectra and mechanisms of triboluminescence in crystalline quartz. --Deglr6328 09:26, 23 November 2006 (UTC)

Yeah, I had one of those as a kid. It was described as a piezoelectric effect. [4] [5] [6] [7] — Omegatron 16:26, 23 November 2006 (UTC)

Well, I really don't know what else I can say. There are several peer reviewed sources attributing the effect specifically to triboluminescence...here's some more [8] [9]. I think the fact that silica exhibits both a piezoelectric effect and triboluminescence accounts for the common public confusion between the phenomena especially because the term triboluminescence is not very well known.--Deglr6328 07:09, 24 November 2006 (UTC)

After doing some more reading, it seems that several different distinct effects are involved in any kind of mechanoluminescence, some of which are caused by cracks and some that aren't. There's luminescence from piezoelectric nitrogen discharge, from elastic deformation, plastic deformation, blackbody radiation from heat at crack edges, chemical reaction and oxidation at new crack surfaces, and others? The word "triboluminescence" is used to mean a few different things, apparently.

Even one of your references says that that luminescence can be caused by piezoelectric discharge through nitrogen, which can in turn induce photoluminescence of the quartz. This is the dominant mechanism in crushing of quartz according to Triboluminescence of glasses and quartz. In Piezoluminescence from a ferroelectric polymer and quartz, they short out the surfaces of the quartz to prevent piezoelectric nitrogen discharges from affecting their measurements of luminescence caused only by elastic deformation.

I'm just going to change it to say "mechanoluminescence".  :-) — Omegatron 02:29, 5 February 2007 (UTC)