Finding the Viscosity of Pitch

ColdChrist writes "The University of Queensland has a page about a 72-year-old experiment on the fluidity of pitch. There's a webcam where you can try to become the first person ever to see a drop of the pitch fall; eight drops have fallen since 1930 and the ninth is now forming. The experiment 'demonstrates the fluidity and high viscosity of pitch, a derivative of tar once used for waterproofing boats. At room temperature pitch feels solid - even brittle - and can easily be shattered with a blow from a hammer', but it does flow, as the pictures demonstrate." I know this is going to bring up glass comparisons, so we'll head those off: glass is not a fluid.

Comments

Did michael read his "glass is not a fluid" link?

[pmc]

Apparently not, or the link would have been "Is Glass liquid or solid?", the actual title of the article. I'll repeat the start of its conclusion here:

There is no clear answer to the question "Is glass solid or liquid?". In terms of molecular dynamics and thermodynamics it is possible to justify various different views that it is a highly viscous liquid, an amorphous solid, or simply that glass is another state of matter which is neither liquid nor solid. The difference is semantic.