Muy explicativo el video Habra que ir con cuidado con los microondas :) Dalton
Cybermani@ C/ Cronista Vte. Beguer Esteve, 8 - B 46900 Torrent (Valencia) SPAIN Tel. 96 108 18 56 E-mail: [EMAIL PROTECTED] http://www.cybermania-torrent.com Canal #cybermani@-torrent de IRC-HISPANO ----- Original Message ----- From: "e" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, April 22, 2002 12:02 PM Subject: Video Re: [Internauta] AGUA EN EL MICROONDAS A les 09:31 22/04/02 +0200, Xavier m'has escrit, >Sincerament, com diuen en Castella "Han oido campanas y no saben donde". Passa't per (l'enlla� ja el va passar un internauta ahir o abans d'ahir) http://howthingswork.virginia.edu/microwave_ovens.html mira la pregunta " Why does water react in a violent and dangerous way when overheated in a microwave oven? CA " i mira el video (a partir del 13 experiment... a veure si ho trobes normal....�s bastant explicatiu, per molt que tiri la forquilla dins del got l'aigua normalment no salta d'aquesta forma) http://howthingswork.virginia.edu/movies/shw28k.rm El que diuen all�, (almenys el que jo he ent�s) �s que si el recipent que cont� l'aigua no t� cap (o prous) impureses o rugositats (cosa que passa amb el vidre), aleshores no hi ha cap lloc a on es poguin comen�ar a formar les bombolles, i per tant l'aigua es va """sobreescalfant""" fins que entra amb contacte amb alguna cosa que li "permet" crear les bombolles, per� com que ja est� tan calenta en lloc de fer bombolletes en fa una de moooolt gran * e * -------------------------------- " Why does water react in a violent and dangerous way when overheated in a microwave oven? CA " Water doesn't always boil when it is heated above its normal boiling temperature (100 �C or 212 �F). The only thing that is certain is that above that temperature, a steam bubble that forms inside the body of the liquid will be able to withstand the crushing effects of atmospheric pressure. If no bubbles form, then boiling will simply remain a possibility, not a reality. Something has to trigger the formation of steam bubbles, a process known as "nucleation." If there is no nucleation of steam bubbles, there will be no boiling and therefore no effective limit to how hot the water can become. Nucleation usually occurs at hot spots during stovetop cooking or at defects in the surfaces of cooking vessels. Glass containers have few or no such defects. When you cook water in a smooth glass container, using a microwave oven, it is quite possible that there will be no nucleation on the walls of the container and the water will superheat. This situation becomes even worse if the top surface of the water is "sealed" by a thin layer of oil or fat so that evaporation can't occur, either. Superheated water is extremely dangerous and people have been severely injured by such water. All it takes is some trigger to create the first bubble- a fork or spoon opening up the inner surface of the water or striking the bottom of the container-and an explosion follows. I recently filmed such explosions in my own microwave (low-quality movie (749KB), medium-quality movie (5.5MB)), or high- quality movie (16.2MB)). As you'll hear in my flustered remarks after "Experiment 13," I was a bit shaken up by the ferocity of the explosion I had triggered, despite every expectation that it would occur. After that surprise, you'll notice that I became much more concerned about yanking my hand out of the oven before the fork reached the water. I recommend against trying this dangerous experiment, but if you must, be extremely careful and don't superheat more than a few ounces of water. You can easily get burned or worse. For a reader's story about a burn he received from superheated water in a microwave, touch here. -------------------------L'INTERNAUTA------------------------------- Per enviar missatges a la llista: <mailto:[EMAIL PROTECTED]> Altes, baixes i informaci� de la llista: <http://www.internauta.net> -------------------------------------------------------------------- -------------------------L'INTERNAUTA------------------------------- Per enviar missatges a la llista: <mailto:[EMAIL PROTECTED]> Altes, baixes i informaci� de la llista: <http://www.internauta.net> --------------------------------------------------------------------
