From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: rec.pyrotechnics
Subject: Re: Fire in movies
Date: 26 Mar 1996 07:41:15 GMT

In article <31577209.6D00@olympus.net>, gsmith <gsmith@olympus.net> says:
>
>The Silent Observer wrote:
>> and insulation) and other agents to make the mixture thixotropic and
>> prevent excessive evaporation.  They're commonly custom made, though I
>> gather one or two of them are available on a semi-commecial basis within
>
>        Okay, I'll bite. It's not in my Websters...I don't recognize the 
>root...Please define "thixotropic". One of those damn terms that's going 
>to be rolling around in my head until I find out!

Thixotropes have time-dependent viscosity. They are liquid materials
which take a "set" on standing, then thin out when stirred and again
take a set when the stirring stops. Oil well drilling mud (bentonite)
is an example. Many cosmetics, paints and foodstuffs and even 
explosives rely on thixotropy to prevent settling in storage or 
transportation.

Thixotropy is often the result of hydrogen bonding between 
hydrophillic suspended particles which form a lattice of filaments
through the liquid and are classified generically as colloidal 
gels. Yoghurt and gelatin both have thixotropic properties.

Once in a while you'll see it spelled "thyxotropic," which looks
nice to me but not to Merriam Webster.

Jerry (Ico)