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Microwave cooking, in fact, will involve lower peak temperatures and shorter times because, effectively, the heat source is nearer the centre of the food.
However, it is not totally obvious that em radiation has no effect on vitamins (double negative, I'm afraid) when you bear in mind that very low fields from the magnetic gizmos you buy to deal with hard water change the way in which limescale forms. They do work, although the result is subtle.
But since the food ends up in our digestive systems, does it really matter if the cooking process has "damaged" the molecules? The food we eat gets torn to shreds in our bodies at a molecular level anyway. The only problem I can think of is that the microwaved molecules become compounds that the body isn't able to chemically process and utilize, or which are toxic.
Microwaves don't penetrate very far into the food....few mm before becoming very weak. The centre is cooked by conduction.
6mm more like. You wouldn't even get 6cm at 27 MHz, let alone 2.45 GHz.
Depends on the food and the temperature. They don't define exactly what they mean by penetration depth. Loss in dB will be proportional to depth... http://220.127.116.11/search?q=cache:ipk7b33xrmEJ:www.bsyse.wsu.edu/tang/tang69.pdf+Microwaves+%2Bpenetration+%2Bfood+%2BdB&hl=en&ct=clnk&cd=45&gl=uk
Math looks right to me! But why would the microwave only penetrate half-way?
From ...http://books.google.com/books?id=xqhCHespUwUC&pg=PA184&lpg=PA184&dq=microwave+temperature+penetration+depth+food&source=web&ots=2brfXqKZsN&sig=eHe2miBqCOj8Ke_XFe0MRBzbUAY#PPA45,M1Thus, MW radiation at 915 MHz penetrates more than the 2450 MHz radiation, ie, 30 versus 10 mm.
Some define penetration depth as being the point at which the RF falls to 1/e of initial power.. 37% or 4.3 dB down.
Looks like it was the wrong link...Thus, MW radiation at 915 MHz penetrates more than the 2450 MHz radiation, ie, 30 versus 10 mm. http://books.google.com/books?id=OycSdO1F0_sC&pg=PA111&lpg=PA111&dq=%22thus+mw+radiation+at+915+mhz+penetrates+more+than+the+2450+mhz+radiation+ie+30+versus+10+mm%22&source=web&ots=A4dcYlAnRj&sig=PWzwx-A1-gXr7Y25Qx7o5vUvcVY
But after another 6mm (12 mm total) the 1 kW is down to 140 Watts. By 18 mm it is down to 51 Watts and by 24mm ..19 Watts.. So essentially very low at 24mm (bit less than an inch).
Most things I cook are in flat rectangular trays.
But as regards if there is any 'damage', (which many conclude is rubbish) to food from microwave cooking many foods may have been processed anyway in the factory with RF possibly with the deeper penetrating 915 MHz.
Others conclude that overcooking or overboiling is the problem and nowt to do with microwaves per se. http://news.bbc.co.uk/1/hi/health/3188558.stm
I have just tried putting wet paper sheets between a satellite dish and the LNB. 3 wet sheets is enough to 'kill' the signal. I think it has to be 4 - 6 dB down before it can't decode the digital TV. So that suggests a 4 - 6 dB loss through only 0.3mm of wet paper. I need the whole of a (dry) 20 mm catalogue to for the receiver to fail. This is at 12GHz of course rather than 2.45.