How does a Microwave Oven works and is it harmful?

Owning a microwave oven would be one of the best investments you can make to enjoy your time in Kitchen. Not only it saves you time, fuel and effort but also it is proven to retain nutrients more efficiently when compared to traditional stove-top cooking. So, if you haven’t been utilizing this genius invention all along, you’ve been probably missing out on the promised nutrition of your veggies and other foods.

However, there has been some discussion on the safety aspect of the use of microwaves in cooking especially in the past when cooking for children. But there also have been subsequent studies and researches in favor of the appliance. Leading health organizations like Harvard medical school and World Health Organisation have cleared the use of microwave ovens of any such accusations. These honorable mentions should single-handedly sweep all allegations.

Knowing already the importance of it and also that it’s incredibly safe to use, one must wonder what kind of sorcery is it. If it weren’t for the 21st century, talking about fire-less cooking would sound utterly absurd. It’s quite unlikely that you’ll find an individual unaware of the fact that microwave cooking doesn’t involve fire.

A Microwave Oven makes it so much more safe for amateurs than traditional cooking methods. But, as with any other gadget, with massive popularity, comes a flooded market. As the competition increases, manufacturers resort to tricky jargon to portray their models as superior to the competition. While they make profits, buyers are at loss. If you’re currently in the market, looking for an resourceful yet cost-effective microwave, you may use our comprehensive guide for the best convection microwaves.

So, how does it really come around? How come a metal box plugged into an electric socket can fetch you delicious meals at the snap of fingers. It is no magic, believe us! All you have is a little bit of science in the picture. If you’re curious too as to how a microwave oven does what it does, read along and find out for yourself.

Introduction to Microwave Oven

Microwaves are technically a segment of the electromagnetic wave spectrum. The electromagnetic spectrum is basically divided into subgroups based on different wavelengths or frequencies. Microwaves have found many modern day applications such as radar detectors, telecommunication gadgets, medical treatment of specific illnesses, etc.

Similarly, certain of their properties make them suitable for cooking purposes which is by far the most common use of microwaves. This ability of microwave energy to cook food was discovered in the 1940s by Dr. Percy Spencer. His experiments revealed that, when subject to a metallic enclosure, high-frequency radio waves penetrate and excite specific molecules present in food resulting in a rise in its temperature.

Components of a microwave oven

Outer casing made up of metal
Interior panels and door made up of galvanized steel.
Cooking cavity made up of ceramic minerals or stainless steel.
Electromechanical components: the magnetron tube, the waveguide and the stirrer fan.

While there are many different types of Microwave oven, almost all of them work on the same technology.

How does a Microwave Oven Work

In extremely simple terms, a Microwave oven heats the food as the sun heats your face on a sunny day i.e via radiation. Radiation is basically the transfer of heat energy through Atmosphere. Microwave ovens are so quick and efficient because they channel heat energy directly to the molecules inside food. In other words, the microwaves transfer their energy to the minute particles in food which leads in rising of the temperature of the food. But the waves are not strong enough to alter the properties of food or change its molecular structure. So, rest assured for the quality of your food is never compromised.

The source of the microwaves inside the oven is a unit called as a ‘magnetron‘. It is located at top of the oven cavity (opposed to radiant heating elements in case of wall ovens). The magnetron is a tubular structure that generates high frequency microwaves. It basically consumes electricity and produces highly energetic 12 cm (approximately 5 inches) radio waves that are responsible for heating up the food placed inside the microwave oven.

The microwaves produced by the magnetron are then funneled to the food compartment through a component termed as the ‘waveguide‘. The waveguide directs the generated microwaves into the food placed on the rotating cooking surface.

We have a yet another component termed as the ‘stirrer fan’. The stirrer fan is located just below the waveguide and it’s sole function is to distribute the microwaves evenly throughout the cooking compartment.

The scattered microwaves in the food compartment get reflected off the metallic walls and keep travelling until they encounter the food surface. Once the microwaves hit the surface of the food, they penetrate and excite polarised particles (H₂O for instance) present in food. The vigorously vibrating molecules inside the food result in rise of temperature of the food.

The food sitting on the rotating cooking surface evenly cooks from outside in as newly generated microwaves are bombarded continuously at the food for the amount of time set by the user. The magnetron stops generating microwaves under the following conditions:

The timer set by the user is completed.
The door of the microwave oven is abruptly opened.

As the magnetron instantaneously stops on unexpected opening of door, there lies absolutely zero chances of interaction with those highly energetic microwaves rendering the user safe and sound. Also, the metallic casing does not allow the microwaves to escape and encloses them as long as the appliance is in operation.

Now, there’s a general misconception among people regarding the differences between a microwave a baking oven. While countertop oven and microwaves look similar, they are far from same with regards to their working. Having countertop baking ovens out of the picture, there’s a great deal of variety in microwaves on the basis of their function and configuration. You get standard microwaves that are used exclusively for simple heating and reheating priced as less as $100, Over-the-range microwaves that double as a range hood and built-in wall oven microwave combos that are to be installed in custom cabinetry. In recent times, manufacturers have introduced speed ovens that tend to cook 2-4x faster than standard micorwaves. GE’s Advantium Microwave series is a competent example in this category.

There might be additional functionalities in some of these types of microwaves, but the basic mechanism of heating stays the same. For instance, microwave drawers are designed in such a way that the heating cavity is accessible from the top and not the front as in countertop microwaves. Similarly, OTR microwaves are equipped with a venting apparatus and work surface lights which makes them ill-suited for countertop installation.

That is pretty much how a microwave oven works and how it is widely customized to serve varied requirements. It is not so complicated after all!

Fun Fact: The discovery of the ability of microwaves to cook food was rather an accident. The magnetron was actually used for research on radar vacuum tubes during the World War II. Who would’ve thought in their rightful minds that we’d be having this technology installed in our kitchens. However, be it an accidental discovery, we cannot be grateful enough for this device has taken cooking comfort to a whole different level.