(11-15-2014, 05:19 PM)PaytonA Wrote:(11-15-2014, 04:30 PM)archangle Wrote: BTW, be careful if you boil water in the microwave. Sometimes, the water will boil suddenly like opening a champagne bottle if you drop something into it. Turn the water off and let it sit for a while before dropping anything into microwave boiled water.
Actually the same thing can happen from boiling water normally although once it is actually boiling it will not occur. It would have to be just before it was ready to start boiling that one might cause an eruption.
Yup, in the microwave, if there isn't something to permit the gas formation associated with boiling, it is possible to superheat the water (get it over 100*C). When you introduce something to the water while it is superheated, it vigorously boils....that champagne bottle effect.
The same can be done on the stove, but most cookware is more porous and has more surface irregularities that keep this from happening. Glass is a fluid, though highly viscous at room temperature (give then 100+ years, and you'll see the distortion in your windows as they flow with gravity)...and typically has a much, much smoother surface than most solids.