5 ms·
Pitch has a viscosity of 3x10^10 P. That's still way less than glass, which (according to this article) is 10^20 P.
by pionar 12y ago
Pitch has a viscosity of 3x10^10 P. That's still way less than glass, which (according to this article) is 10^20 P.
- lisper 12y agoSo if time to form a drop is linear in viscosity (I have no idea if it is or not, but it seems like a plausible guess) then it would take longer than the present age of the universe for glass to form a single drop. In those circumstances, saying "glass doesn't flow" seems like a pretty darn good approximation to the truth.
- Dylan16807 12y agoThat's within an order of magnitude of lead! Does lead flow? The article dismisses it but only in a casual way.
- jdmichal 12y agoWell, we could test it. Put lead into a funnel, suspend the funnel above a beaker, and wait for a drop. Assuming the scale is linear, you should only have to wait around 80 to 130 years based on pitch experiments: http://en.wikipedia.org/wiki/Pitch_drop_experiment http://en.wikipedia.org/wiki/Pitch_drop_experiment More seriously, there's possibly a viscosity at which gravity is no longer enough acceleration to overcome whatever mechanisms are holding the atoms together. If we assume that metallic lead does not exhibit any flow on Earth, then we can estimate this as being between 10^10 and 10^11P at g.