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Microwave Experiments Cause Sponge Disasters
gollum123 writes "Reports about a study that found microwave ovens can be used to sterilize kitchen sponges sent people hurrying to test the idea this week — with sometimes disastrous results. A team at the University of Florida found that two minutes in the microwave at full power could kill a range of bacteria, viruses and parasites on kitchen sponges. They described how they soaked the sponges in wastewater and then zapped them. But several experimenters evidently left out the crucial step of wetting the sponge. "Just wanted you to know that your article on microwaving sponges and scrubbers aroused my interest. However, when I put my sponge/scrubber into the microwave, it caught fire, smoked up the house, ruined my microwave, and pissed me off," one correspondent wrote in an e-mail to Reuters."
How else did they expect it to work? Of course you need the god-damn water in the sponge. Microwaves have a wave length measured in the centimetre. The size of a bacterial spore is a couple of orders of magnitude smaller The size of a bateria is a lot smaller than this again.
This means that if you wanted to destroy the blighters with radiation alone you have to choose a frequency a lot higher than microwaves, otherwise there will be areas in the minima of the standing wave that won't heat sufficently to kill the microbes.
The mechanism for steralisation is through the formation of steam that kills the majority of the nasties - not the microwave energy itself.
Simon
The microwave steralizes the wet sponge because it makes the water hot enough to kill anything living. The same effect can be had by dunking the sponge in a pot of boiling water.
... and in the DRM, bind them.
of course, those of us with children and bottle sterlisers know that placing water and objects in a microwave leads to the steam cleaning them... "well duh" was my reaction when i saw this "news" item yesterday....
People may not understand microwaves, but the original article I saw gave the following advice:
Maybe some news sources edited the article down to a short filler piece and left out some of these crucial details.
... how else did _you_ expect it to work?
A simple question for you: water molecules, are they larger or smaller than the bacteria and spores to be killed?
Last time I've checked, the wavelength used in the microwave is about 12.5 cm. Sure, the bacteria are much smaller than that, but is it at all relevant?
KnightTristan
Calling these people stuipd only makes you look like an arrogant asshole. For most people, a microwave is a black box contraption in their kitchen that makes food hot. Sure, they also know that you shouldn't put a fork or knife in, but have no idea why. This isn't because they're stupid, it's because they're ignorant about the inner workings of that particular machine in their kitchen.
No, it's because they're stupid. No knowledge of inner working of microwave required to understand that putting flammable things into a device that makes them hot IS NOT A GOOD IDEA.
no, they're not stupid. they put shit in a "black box that makes food hot" and it caught fire. WOW! color me surprised. I'd say that's pretty stupid.
No. The media told them "if you put shit into a black box that makes food hot it will sterilize it".
So they did. And it caught fire... because the media forgot to mention that you should use *wet* shit.
That is totally different to waking up one morning and trying to microwave a random object to see what would happen.
Humans set goals which evolution can work for or against. In the case of the goal "All humans become smarter and more peaceful, and achieve worldwide safety and comfort, and stop shooting each other over which hand the invisible man in the sky wants you to wipe your a** with", the goal is nearly universal, at least among men who have thought at all about the optimal future state of mankind.
It is implied, and obvious to everyone except for pedantics like yourself, that value judgments about evolution are using that goal as the standard of value. And therefore evolution can move in 'right' or 'wrong' directions, relative to that goal.
FATMOUSE + YOU = FATMOUSE
Because microwave ovens work best by vibrating water molecules. As they vibrate friction causes them to turn to steam which is what sterilizes the sponge in the first place.
How else did they expect it to work? Of course you need the god-damn water in the sponge. Microwaves have a wave length measured in the centimetre. The size of a bacterial spore is a couple of orders of magnitude smaller The size of a bateria is a lot smaller than this again.
...Or maybe someone who feels superior to "the masses" need to really review the concept of dielectric heating.
So, are you suggesting that any body shorter than the wavelength of microwave radiation (12 cm) will be left unheated? Neat! That must be why my pizza rolls are still frozen when I get them out.
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
Why not just put your sponges in a pot of boiling water for two minutes and skip all the exploding parts? It even works on metal scouring pads.
The days of the digital watch are numbered.
**(For the record, I don't downmod comments)**
The whole robots/unemployment thing has been hashed out repeatedly, argued even before there was a term/name for "robots". The following is the outline of personal notes i used for a speech i had to give in speech class a few years ago: