Cool Tech/Geek Video of the Day

[AggieMike88]

Thread to post and discuss cool videos of a tech or geek nature

First up: Slow mo of Glass Breaking to Thermal Shock

 

[flhrci]

That's pretty neat. Not sure why Pyrex does that but I had heard of it happening. Cool vid. Might google the why's later.

 

[Cap'n Jack]

Although the label reads "pyrex", that is almost certainly soda-lime glass which shatters more easily under thermal stress (they mention that in the video). Soda-lime glass has a higher coefficient of expansion than type 33 borosilicate glass ("real pyrex"), and can't stand thermal stress as well. As to why the entire cup explodes, the glass is under stress created by the molding and cooling process. They try to reduce this stress after molding by heating, followed by cooling, in a Lehr oven, but the process isn't perfect. This stress is relieved as the glass breaks. The stress is more difficult to remove in thick parts of glass, such as the handle, which is why it sometimes turned back to sand.