Transcript: Microwaving Eggs

Food Science
Episode “Microwave eggs“

Dr. Kiki Sanford: Hi, I am Dr. Kiki Sanford and today on Food Science we are talking about microwaves. Have you ever wanted hardboiled goodness but didn’t have the time to dedicate, many of us have probably resorted to the microwave at one point or another. I know that I have tried to pop an egg into the microwave on at least one occasion but then you learn your lesson. Anyone having to clean a egg out of the microwave probably won’t repeat the mistake but what just happened?
Microwave ovens work by creating electromagnetic waves in the form of microwaves that energiz the electrons and molecules. Microwaves have wave lenghts 1mm to 1m in length. Microwave ovens have a device inside of them called a magnatron which produces strong and rapid pulses of microwaves. DC pulses are created within the microwave oven Power Supply which electrically heat a cathode causing it to release electrons. With the help of the special magnet beams of the electrons are sent to special chambers that resonate at 2.5 ghz, the frequency ad which might waive ovens a operate.
A antenna then transmits the current from the magnatron to the cooking chamber as microwaves. Microwaves primarily affect molecules that are polar in nature by making them rotate to remain aligned with the alternating electrical field of the microwaves. As they rotate some of the molecules bump into each other the resulting friction changes kinetic energy into heat. Microwaves can pass through non polar materials that do not conduct electricity and do not contain water. This lets them penetrate more deeply into foods and more rapidly than conventional cooking methods.
In the case of our pour egg here the microwave excited the water molecules inside the egg to boiling, this lead to steam build up inside of the egg that increased the pressure enough to cause it to explode. But is it possible to cook an egg in the microwave in its shell without having it explode? I found a gadget that says it will let me do just that. The microwave egg boiler.
This microwave egg boiler consists of a lid, a aluminum tray, and a well for water. But aluminum in the microwave? Well it turns out that as long as there are no sharp edges notice that this tray is nice and round, there is no place for the electrical current created in metal objects by microwaves to collect and create a spark.
If you inspect your microwave you’ll notice that the cooking chamber is metal walled, this keeps the microwaves inside of the microwave. Now look carefully at the glass in the door, the holes in the screen are smaller than the wave lenghs of the microwave which also helped keep them from escaping. The thickness of the metal also comes into play, lower resistance leads to less heating, the thicker the metal the lower the resistance so this tray should be just fine. The lid is lined with aluminum so that the eggs are completely shielded from bombarding microwaves.
You fill the well with water, put the eggs on the tray, set the lid on top and make sure it is snug, and then set the microwave to cook and you wait. The end result here is that the water is heated creating steam which heats the aluminum tray and cooks the eggs from the outside in via conduction, rather than the eggs heating internally, creating steam and exploding. That is hot, see what nice cooked eggs. And no mess to clean up, yeah. But remember it’s not just food, it is science, oh yeah, its science.