Hi, I’m Doctor Kiki Sanford and today on Food Science, we’re talking microwaves. Have you ever wanted hard boiled goodness but not 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 popping an egg into the microwave on at least one occasion. But then you learn your lesson. Anyone having to clean egg out of a microwave probably won’t repeat the mistake. But what just happened?
Microwave ovens work by creating electromagnetic waves in the form of microwaves that energize the electrons in molecules. Microwaves have wavelengths from one millimeter to one meter in length. Microwave ovens have a device inside them called a magnetron which produces strong rapid pulses of microwaves. DC pulses are created within the microwave oven’s power supply, which electrically heat a cathode causing it to release electrons. With the help of a strong magnet, beams of electrons are sent to special chambers that resonate at 2.45 gigahertz, the frequency at which microwave ovens operate. An antenna then transmits the current from the magnetron 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 converts kinetic energy into heat.
Microwaves can pass through non-polar materials that do not conduct electricity and that do not contain water. This lets them penetrate more deeply into foods more rapidly than conventional cooking methods.
In the case of our poor egg here, the microwaves excited the water molecules inside the egg to boiling. This led to steam buildup inside the egg that increased the pressure enough to explode. But is it possible to cook an egg in the microwave in its shell without having it explode? I’ve found a gadget that says it’ll let me do just that – the microwave egg boiler.
This microwave egg boiler consists of a lid, an 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 this tray is nice and round, there’s 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 the microwave. Now look carefully at the glass in the door. The holes in the screen are smaller than the wavelengths of the microwaves which also helps 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 the bombarding microwaves. You fill the well with water. Put the eggs on the tray. Set the lid on top. Make sure it’s 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 creating steam internally and exploding. That’s hot.
See what nice cooked eggs? And no mess to clean up. Yey! But remember, it’s not just food. It’s science. Oh yeah, it’s science.
All original shows, all in HD, from onnetworks.com.
Transcription by:
Scribe4you Transcription Services