Microwave ovens are very common these days and there are some points that need to be brought to the users attention.
No two models and makes are alike. For instance there are different wattages and each is set relatively close to the same at the factory, but they will be different. So cooking times will vary slightly with each. Also, all of them have what could be called a “hot spot” where the rays are more concentrated, you can check out the marshmallow test below to find out.
Also, I’ve never seen any insulation around the outside of cooking cavity of a microwave, and that includes the convection combination models as well.
You can view the marshmallow test in action and find out how to determine the wattage of your microwave using a new learning tool Nebraska Extension and North Dakota State University Extension developed.
Visit http://tinkerlab.com/microwave-marshmallow-experiment to see the this experiment.
If you are curious about the “marshmallow test,” here is how to do it. Use a microwaveable plate or flip the turntable upside down so it does not rotate.
Line the plate or turntable with miniature marshmallows. Place in the microwave oven, then set the timer for one minute. Watch carefully. If the marshmallows begin to burn, turn off the microwave oven. The marshmallows that expand first show where your microwave oven’s hot spots are. Remember that uneven cooking (hot and cold spots) can lead to undercooked food that is unsafe to eat.
there’s a lot more information that you can find interesting so to see t he full article for the above marshmallow test click this link: http://www.inforum.com/event/article/id/433044/group/News/