Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Pyrex "Explosion" Conserves Energy?

First I will note that the amount of kinetic energy involved in
this explosion is minuscule relative to the internal energy change
produced by heating the Pyrex dish. You should not be surprised to
see such an effect on that basis.

The coefficient of thermal expansion of Pyrex is smaller than that
of many glasses, but it is not zero, and it is greater than that
of fused quartz. It is possible that the interior of your Pyrex
dish was much hotter than its surface at the moment of explosion,
and that the surface ruptured under the resulting stress.

I used to do a trick with liquid nitrogen and a Pink Pearl eraser.
If I placed the eraser in liquid nitrogen for about thirty seconds
starting from room temperature, and then removed it from the cold
and placed it on an insulating tabletop, the eraser would often
explode in a manner similar to what happened with the Pyrex dish.
The effect is not highly reproducible, but it can be spectacular
when it works.