Re: [math-fun] glasses are liquids?
You all might enjoy the "Pitch drop experiment" "The most famous version of the experiment was started in 1927 by Professor Thomas Parnell of the University of Queensland in Brisbane, Australia, to demonstrate to students that some substances that appear to be solid are in fact very-high-viscosity fluids. Parnell poured a heated sample of pitch into a sealed funnel and allowed it to settle for three years. In 1930, the seal at the neck of the funnel was cut, allowing the pitch to start flowing. Large droplets form and fall over the period of about a decade. The eighth drop fell on 28 November 2000, allowing experimenters to calculate that the pitch has a viscosity approximately 230 billion (2.3Ã1011) times that of water.[1] The ninth drop is expected to fall in 2012 or 2013. [2]" http://en.wikipedia.org/wiki/Pitch_drop_experiment The _live_ "pitch drop webcam" is located here: http://smp.uq.edu.au/content/pitch-drop-experiment At 02:57 PM 12/26/2012, Warren Smith wrote:
But insofar as glass is amorphous there are arbitrarily small energy barriers against changes of configuration and so it is technically a liquid, even though in practical terms it's a solid.
Brent Meeker
--I deny this. I claim, it is at least in principle possible for an amorphous solid to exist in which any change requires at least a fixed energy change. One simple example would be usual periodic packing of bricks, but each brick is in one of 2 orientations ("upside down" or "rightside up") selected randomly, and any switch takes 1 electron volt to get you over the barrier.
Also, re the claim glass is a "liquid with very high viscosity" how about solid crystalline metals? They can be deformed. In fact, they are a lot more deformable than glass. So are they liquids with high viscosity?
participants (1)
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Henry Baker