Like many inventions, microwave ovens for modern kitchens are the product of a completely unrelated scientific experiment. In the mid-1930s, quite intensive experiments were conducted with a magnetron, a device that emits waves in the ultra-high range. During the work, an interesting effect was discovered – the employees of the American laboratory managed to heat the sausages to readiness without using fire. They accidentally left them in the range of the microwave generator.
Later, this result was confirmed by new experiments, and enterprising engineers received a patent for “radar ovens” – a prototype of today’s microwaves. Initially, they were used only for defrosting products of strategic purpose, but a decade later (in the early fifties), Japanese companies began to produce similar devices, adapting them for kitchen needs. Let’s figure out what it is – a modern microwave oven?
What does a microwave oven consist of?
Many people are familiar with the appearance and shape of microwave ovens, but not everyone knows how a microwave oven works. Almost all models of microwaves have a basic structural configuration, which includes:
- A chamber made of special alloys, in which heated food is placed;
- The special design of the door does not allow radiation to go outside the camera;
- Play ventilation holes;
- Electronic control unit with external panel;
- Air ducts;
- A roller for rotation and a glass plate for products;
- Gear motor;
- Elements of electrical circuits.
The inner, metal part of the camera shields microwave waves, protecting the user from the effects of radiation. The glass door is also made with the inclusion of a shielding metal mesh.
The electronic control unit does not allow the use of the oven in the open, blocking its activation. It also controls the supplied power and the set time of operation.
responsible for the timer, program launch, sound signals, can be set independently on the control panel.
But that’s not all a microwave oven is made of. Heating heaters or infrared lamps (grill) can be added to the basic design, for example, as in the Beko MGC20100S, and a convector, which is a fan inside the chamber.
What are microwaves?
Some users are afraid to equip their kitchens with microwave ovens. Having read on the Internet about the harm of microwave radiation, people do not want to be exposed to “harmful” rays and do not try to understand the principle of using the energy of electromagnetic waves. Knowing the nature of microwaves will help to understand exactly how a microwave oven works and what is the source of heat in it.
Everyone knows that the source of heat for all living things on our planet is the Sun. Solar energy is delivered to the Earth using electromagnetic radiation. It is what gives us the bright color palette of the surrounding world: after all, COLOR is the radiation that we SEE. And the waves that we cannot see are also included in the SPECTRUM of EM radiation: X-rays, infrared, radio waves, ULTRAVIOLET. Microwaves also belong to them. These are almost the same radiations as radio waves, which ensure the operation of telephones, televisions, and the Internet.
They differ among themselves in two parameters – wavelength and frequency of oscillation. It should be noted that microwaves in household microwave ovens do not have an ionizing effect like ultraviolet or gamma radiation, they cannot cause changes in cells or harm a person. They don’t have enough energy for this. They can only heat food with their energy. In addition, the internal housing of the microwave oven is made of metal alloys, fully protecting a person from even such, safe, radiations.
How does a microwave heat food?
Let’s figure out why a microwave oven heats up food. Electromagnetic waves, affecting the charged water molecules of the food placed inside it, force them to oscillate at an ultra-fast speed. With such a high-frequency oscillation, the molecules begin to rub against each other, due to which they heat up sharply.
It happens like this:
- Turning on the microwave oven activates the operation of the magnetron – the microwave generator.
- The waves are directed inside the microwave housing, constantly reflecting off the inner walls.
- The water molecules contained in the food begin to work like microscopic electromagnets, changing the direction of the electric field about 5 million times per second.
- Accelerating under the influence of microwave energy, the molecules quickly gain temperature due to movement, transferring the heat inside the dish.
Interestingly, not all products can be heated in a microwave oven. For example, oil. It does not contain enough charged molecules – dipoles, which are the main molecules heated by a microwave oven. But water can be brought to a higher temperature than during normal boiling. It is not even possible to see through the glass door – there is no steam condensation. Therefore, you need to be careful when taking out a cup with such boiling water – disturbed overheated water can boil and splash out of the container right in your hands.
How can a microwave oven affect a person? No way, if you follow precautions. So, experts warn against using ordinary plastic for heating food, some of its types emit dangerous chemicals when heated. In addition, it is considered wrong to reheat slightly sour food. The fast process does not have time to kill disease-causing microbes, it is better to boil such food. And one more warning: in order to avoid an electric arc inside the housing, you cannot put food in foil or on a plate with a golden pattern in the oven. This can not only break the stove itself, but also lead to a fire. Knowing how a microwave oven heats food, and following the rules of caution, you can not worry about the health of your loved ones.
It is interesting to read: or microwave – 3 key parameters for the right choice
Properties of food after heating in a microwave oven
Opponents of microwaves, in addition to horror stories with harmful radiation, argue their fears with the molecular change of products. However, its structure itself does not change at all when heated – it’s just that the molecules move quickly. Accordingly, the properties and composition of food remain the same.
Arguments that the food does not taste the same as freshly prepared can be refuted by the very nature of microwave heating. If the dish in the oven or pan heats up more strongly from the outside, then in the microwave the heating is much more uniform and is carried out throughout the entire thickness of the product. And the moisture inside the heated dish is distributed differently. But the vitamin composition in a microwave, such as the Electrolux EMM20000OK, remains more complete than with traditional heat treatment.
However, there are products that doctors do not recommend putting in a microwave oven. Experts do not recommend heating breast milk in it, as well as eggs and any other products in a single shell – they can explode and contaminate the entire interior of the microwave.
There are no official bans on the use of microwave ovens in any country. Therefore, to use it or refuse it depends only on the person himself. It should be noted that a microwave oven is considered a very popular appliance not only for the home, but also in modern offices. And many small cafes and hotels offer their customers the opportunity to have a snack with hot food heated in a microwave oven. Most experts believe that proper equipment and compliance with the rules of use minimize the negative impact of radiation in microwave ovens.
By the way, users usually compare a microwave oven with an oven. Here are the key performance indicators of these two units: