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I'm a Mechanical Engineer, not a Physicist, but I think the following conditions make it a theoretical possibility: 1. The water must be very pure without any contaminants or minerals that would help precipitate the formation of bubbles. 2. The container must be smooth at the microscopic level and very clean. 3. The liquid must be held very "quiet" during the heating process, i.e., no vibration or outside disturbance. 4. The heating process must be fast. 5. The liquid must be heated somewhat beyond 212 to get a substantial explosion. The reason is the latent heat of evaporation would very quickly lower the temperature to below the boiling point if the temperature was just at or slightly above 212. 6. Surface tension could also have a bearing on the phenomenon. There may be more, but these are the significant ones. As to your adding instant coffee to hot water, I believe that is related to 1 above in that the coffee is a "contaminant" that helps kick the process. Some chemicals actually lower the boiling point temperature, therefore if you add it to water at 200 degrees F, it could start boiling if the mixture lowers the boiling point to something less than 200. (We achieve the same type effect at the other end of the scale by adding salt to ice (or water) to lower the freezing point. If there was a way to suddenly remove the salt from liquid water at say 20 degrees F, it would instantly freeze. Personally, I never heat my coffee water to the boiling point (cause I need to drink it as soon as possible, I am not a morning person!) unless doing it over a campfire (boiled coffee). I heat it based on time (1 minute and 40 seconds, where 2 minutes would make it boil - in my microwave oven - everyone's would be different). It's been 41 years since college, so don't you people out there nit pick this dissertation too much! > ---------- > From: Robert A. Fink, M. D.[SMTP:[log in to unmask]] > Sent: Tuesday, September 12, 2000 3:42 PM > To: Hawkins, Darwin > Subject: Re: NON PD - Micro wave caution > > On 12 Sep 00, at 11:29, Hawkins, Darwin wrote: > > > Do you honestly think if something like this could happen as easily as > > inferred, that there would not be warnings plastered all over the > > microwave literature? > > Darwin, > > My follow-up post (about what happens when you add instant coffee > to microwave-heated water) represents a true experience. Is that to > be considered a hoax, also? Can you explain the physics? > > > Best, > > Bob > > > Robert A. Fink, M. D., F.A.C.S. > Professional Corporation > 2500 Milvia Street Suite 222 > Berkeley, California 94704-2636 USA > Phone: 510-849-2555 FAX: 510-849-2557 > WWW: <http://www.dovecom.com/rafink> > > "Ex Tristitia Virtus" >