Interesting 16/sec ball bearing production process: https://www.youtube.com/watch?v=19duYMdiXi0 Falling raindrops form cabochons: https://www.youtube.com/watch?v=a9CRrGvQwe0 1961|2 freshman chemistry lecturer demoed Prince Rupert's Drops, and then something more interesting. (Prince <othername>'s Drops? Google fails me.) Hollow, thick-walled glass blobs, open at one end. He hammered nails with one, then wrapped it in a towel, dropped in some carborundum crumbs, BAM! --rwg On 2017-10-22 11:57, Dan Asimov wrote:
Henry got that right — in fact, something quite interesting happens, as Wikipedia says:
----- Prince Rupert's Drops (also known as Dutch or Batavian tears) are toughened glass beads created by dripping molten glass into cold water, which causes it to solidify into a tadpole-shaped droplet with a long, thin tail. These droplets are characterized internally by very high residual stresses, which give rise to counter-intuitive properties, such as the ability to withstand a blow from a hammer or a bullet on the bulbous end without breaking, while exhibiting explosive disintegration if the tail end is even slightly damaged. In nature, similar structures are produced under certain conditions in volcanic lava. -----
more at https://en.wikipedia.org/wiki/Prince_Rupert's_Drop.
—Dan
Henry Baker wrote: ----- If you don't remove the air in such a column, you're likely to get shot that is more raindrop-shaped than sphere-shaped. -----
I wrote: ----- ... I'd try dropping molten glass some distance through the air to make it form into a sphere, and have it land in water to make it rigid.
—Dan
Henry Baker wrote: ----- It's the year 1500, and some wealthy patron wants a transparent glass and/or rock crystal sphere perhaps 6-8" in diameter.
How would you fabricate it? ... ... ----- -----
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