Microwave Safty

[edwina]

Does anyone knows if it's safe to microwave a silvery colour aluminium (mixed with metal) dish that you can find in $10 shop or dept stores? I found that my maid used it to cover dishes when she heats up food for us in the microwave.

 

[barbwong_130]

I think that the reason we don?t use metal in microwaves is because it might cause a fire rather than any problem with the cooking.

There is a web site called Unwise Microwave Oven Experiments, http://www.amasci.com/weird/microexp.html

Q: If I put a fork in the Microwave, will it destroy the oven?
A: Nope, this is a myth, but it has some roots in reality.
In order to safely use metals inside a microwave oven, the cook has to learn numerous complex and mysterious rules in order to avoid fires and undercooked food. For example, thin metal will heat up fast in the oven, and may cause fires. The famous problem of the staple in the paper popcorn bag comes to mind, where the staple heats up and sets fire to the bag. And if a metal object in the oven is lightly touched to another one, or touched to the metal wall of the oven, an electric arc might ignite at the contact point. If not stopped it can set fire to the oven. In the higher power ovens when the amount of food is small, sharp points on metal objects can initiate a corona discharge, a "Saint Elmo's Fire," which behaves the same as a flame and can set fire to the food and the oven if allowed to continue for long.
So, it's much easier to totally ban the use of metals in microwave ovens. The alternative would be to send everyone to school to learn the complicated rules!

 

[edwina]

How about radiation? I remember during our old school days, it was taught in our Physics lesson that when you heat metal in microwave, it will emit certain type of harmful radiation ( which will be absorbed by the food), and it might be fatal to human beings.

Any scientist out there who can confirm this?

 

[kevin]

Don't worry about the radiation, it is non-ionizing "electromagnetic" radiation similar to radio waves. Microwaves cause the water molecules in food to vibrate and hence heat up and cook. The microwave energy is changed into heat as it is absorbed by the water in the food and therefore cannot make food radioactive.

You only need to worry about ionizing radiation such as from nuclear waste. Of course microwaves can be harmful if you put your hand (or head) in to the oven as it will heat up the water molecules in your body and cause damage.