Quote:
Originally Posted by omon
i suspect your glass had flaws, like a hairline crack or a air bublle, cuz in my family boiling water in microwave is everyday task for many years, in any cups we did it, foam, glass, china, plactic. not once it exploded.
meat sometimes does explode.
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It might have had something to do with how long I set the timer (too long).
To have the water "blow up", you need a container that's fairly flawless and does not absorb microwave radiation. The reason is this: Thermodynamically, water likes to be a gas at 100C once it has absorbed the latent heat of vaporization. However, the laws of thermodynamics do not state how quickly water has to turn into a gas or the manner in which it does this. That depends on microscopic processes. If you have a kettle that's being heated from the bottom by a flame, then hot spots and imperfections could cause little bits of water to vaporize at a time, causing the bubbling of boiling water. However, in a microwave, if you have a container that's fairly transparent to the microwave radiation, the water in your container will heat up uniformly. Since most glass containers also have fairly smooth and perfect surfaces, there won't be enough sites to nucleate steam bubbles. Instead, the entire bowl of water will continue to absorb heat at 100C until the entire bowl of water has absorbed enough latent heat to vaporize all at once. At that point, any slight disturbance of the water will cause an "explosion" like what happened at my parents' house.
Of course, this depends on the material of your container, the geometry of the microwave's heating coils, how long you've heated the water, etc. Just be careful not to heat your water for too long. For safety, you might consider dropping a few tea leaves or something else that's insoluble and harmless in the container to prevent accidents.
Disclaimer: Of course I'm not an authority on microwaves so this is just some friendly advice and I take no responsibility for any accident or injuries.