Alan Braggins wrote:
In article , Big Grin wrote:
D.M. Procida wrote:
"Big Grin" wrote:

True - but as glass is classed as a fluid (look it
up) then that will eventually sink to the bottom.

Glass isn't a fluid and it doesn't flow. That it does is an urban
legend of astonishing durability.
[...]
discussions - so shall we agree to disagree?

It won't change the fact that he's right and you are wrong.

Alan,


Now you have made such a dramatic statement, please prove absolutely
convincingly by scientific methods that I am wrong - please supply all
calculations and experimental data to confirm your theory.

to the bottom in one big amorphous lump in a few millions years.
Come back to the group then and let us all know who was correct. ;-)

Or you could save time by looking at a piece of volcanic glass a few
million years old, and noticing it still has sharp edges. On a
slightly smaller timescale, you can see sharp engraving on Roman
glass in museums.

Now, if that is your theory that glass is not a liquid, then please go to
the bottom of the class for lack of effort.

Now a question for you - what is the most prolific solvent?

Big Grin

PS do *YOU* know where I can get some glass wedges from to hold up my
sagging window glass?

It's starting to get bloody draughty in here now. and I don't want to
replace it as I'm not sure that the new glass won't suffer the same fate.
:-(

"Big Grin" wrote in message
...


PS do *YOU* know where I can get some glass wedges from to hold up my
sagging window glass?

It's starting to get bloody draughty in here now. and I don't want to
replace it as I'm not sure that the new glass won't suffer the same fate.
:-(

Have you forgotten to turn the windows every two years like you should?

dennis@home wrote:
"Big Grin" wrote in message
...


PS do *YOU* know where I can get some glass wedges from to hold up my
sagging window glass?

It's starting to get bloody draughty in here now. and I don't want to
replace it as I'm not sure that the new glass won't suffer the same
fate. :-(

Have you forgotten to turn the windows every two years like you
should?

Dennis,

I've tried turning them upside down and that does the trick for a while -
but then it starts to sag again.

Bloody annoying having to turn the stuff every million years or so! *eg*


I really must leave this modern technology alone and go back to milking my
three legged cows. ROLFL


Big Grin

Huge writes:

On 2009-02-23, Alan Braggins wrote:

Or you could save time by looking at a piece of volcanic glass a few
million years old, and noticing it still has sharp edges. On a slightly
smaller timescale, you can see sharp engraving on Roman glass in museums.

My wife has two pieces of Roman glass (she collects "art glass"). Neither
of them show any evidence of flow, and both are well over 1000 years old.

Do they show evidence of devitrification? (I'd expect the
glass to be a little cloudy or even have visible crystals.)

What's always struck me about the myth that glass (which
does have the molecular organisation of a liquid) flows is
how, supposing that it flowed, could the rearrangement of
molecules that that entails avoid hitting the more stable
crystalline arrangement, at least microscopically? And once
it starts crystallising, it'll keep going, just as if you
have super-cooled water, a tiny disturbance can make it turn
to ice in a twinkling (not that undisturbed glass is going
to do anything quickly).

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2009-01-31)

Jon Fairbairn wrote:
Huge writes:

On 2009-02-23, Alan Braggins wrote:

Or you could save time by looking at a piece of volcanic glass a few
million years old, and noticing it still has sharp edges. On a slightly
smaller timescale, you can see sharp engraving on Roman glass in museums.
My wife has two pieces of Roman glass (she collects "art glass"). Neither
of them show any evidence of flow, and both are well over 1000 years old.

Do they show evidence of devitrification? (I'd expect the
glass to be a little cloudy or even have visible crystals.)

What's always struck me about the myth that glass (which
does have the molecular organisation of a liquid) flows is
how, supposing that it flowed, could the rearrangement of
molecules that that entails avoid hitting the more stable
crystalline arrangement, at least microscopically? And once
it starts crystallising, it'll keep going, just as if you
have super-cooled water, a tiny disturbance can make it turn
to ice in a twinkling (not that undisturbed glass is going
to do anything quickly).

Indeed. I think the truth is that glass is a supercooled liquid, but no,
it doesn't flow at room temperatures at all appreciably even in 1000 years.