Casserole Science (With Built In Profit)
Good old Tesco’s: Britain’s biggest and richest supermarket. Not only are they able to still eek out impressive profits in these dark financial days, but they also seem to be able to change the effect of microwaves upon metal. How else can we explain this wonderful cast iron Le Creuset casserole which also appears to be MICROWAVE SAFE. That’s Cast Iron + Microwaves.
Can any budding physicists tell me what they think would happen and if anyone has a microwave and a similar Le Creuset cast iron casserole dish they want to test it on please do. Else follow my three step plan to instant profit:
1) Buy casserole from Tesco
2) Microwave (stand back)
3) Sue Tesco for false advertising
4) PROFIT
Pete Baran in FT • 121 views
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They’ve got quite a range of pots and pans that they call ‘microwave safe’. I wonder who will be the first person to blow up their microwave and sue.
It’s not necessarily going to cause problems (though I wouldn’t try it!).
The reason that microwaving metal objects can be a bad idea is that the electromagnetic wave used to transmit energy into your food creates potential differences across the surface. Because metal is a conductor, this results in current flowing through the object as electrons move to neutralise the potential difference.
If your object has poor conductivity (eg. if it is thin) this will result in large amounts of heat, which can damage the metal object, your microwave, or (most ghastly of all) your dinner! Metal objects that converge into points can result in relatively close areas of different potential being separated by air. Sparks will fly as electrons bridge air gaps to equalise potential.
Cast iron pots are relatively conductive and don’t converge to points, so should safe in a microwave.
Conductive surfaces also reflect electromagnetic waves. This will prevent your food from being heated if you leave the lid on your pot – also, if there is nothing to absorb microwaves while the unit is being operated, you will eventually cause damage to the magnetron.