The image shows an electric device designed for heating food and baking semi-finished products, called a microwave oven, in the shape of a box with front and back rectangular sides and right and left square sides.
The oven is viewed from the front and from its inside, through the heat-resistant glass of the door, where the food may be touched.
The oven outer shell is represented by a bold outlined rectangle.
The oven cavity, where the food is heated, is located on the left side and is separated from the mechanical components of the internal structure by a wall rendered in the center by a thickened vertical line.
The magnetron or the source of radiation, is the device that converts electric current into microwaves, shown in the upper right, through an embossed square, cut from the upper corners, with a small blank semicircle on top, highlighting the tube of the magnetron through which radiation is transmitted.
To the left of the magnetron is waveguide that guides the microwaves to the inner cavity, being rendered by a horizontal arrow, with the tip directed to the left.
Above the oven cavity is mounted a wave stirrer or a mode stirrer, a system of constant distribution of microwaves in the inner cavity, which evenly heats the food.
The wave stirrer is shown at the top, center-left, through a thin, thickened horizontal rectangle.
The step-up transformer, which raises the voltage to a level of a few kilovolts, is represented on the bottom left, by an embossed square, with its center blank.
Under the transformer, behind the oven, is the cable and the plug power cord, which is inserted into the socket for power supply.
It is shown in the lower right corner, by a thickened horizontal line, respectively the cable, at the end of which is illustrated an embossed circle with two teeth, respectively the power plug.
The oven cavity has a round support at the base, called the turntable, that rotates during the heating process of the food placed on a plate above, the image showing a chicken drumstick, marked embossed.
Currently, there is not a faster method to heat food, or even to prepare it, other than using the microwave oven. In just a couple of seconds we can heat water for a hot cup of tea. Moreover, in only a matter of minutes we can heat our food without having to stir it and without the fear that it might stick to the bottom of the plate while being heated. But let’s see how the microwave oven actually works.
Unlike the classic electric ovens, where the heating is achieved through resistors, the microwave oven uses very high frequency electromagnetic waves. The main components of a microwave oven are:
- the magnetron, a device that converts the electric current into microwaves, meaning electromagnetic radiations;
- the transformer, which has the role of boosting up the voltage by several kilovolts;
- the inside of the oven, where the food is being heated;
- a round base that is inside of the oven, onto which the food container is placed in order to heat it up;
- various safety elements;
- control elements, such as buttons, touchscreens, mechanical switches.
Upon turning on the microwave oven, the round base from inside onto which we have previously placed our food container starts to spin. This way it ensures proper heating from all sides, because the radiations would not focus just on one point of the container, but they can reach all around it. The microwaves make the water molecules from the food to spin at a very high speed. As a result of the friction force between those molecules, heat is created and this heat created directly inside the water molecules within food is what makes food heat up really fast.
The main advantage of the microwave oven is the fact that it can heat food very quickly. Its biggest drawback is however not being compatible with just any sort of food container unless it is made of ceramics or heat-resistant glass. It is not recommended to heat food in plastic plates and bowls, as the particles found in these types of containers can mix with the food molecules during the process of heating. However, there are some plastic food containers on the market which are safe to be used inside a microwave oven. The use of metallic plates is strictly prohibited and highly dangerous as it may cause explosions and can lead to appliance malfunction.
Did you know that in 1946 the American engineer Percy L. Spencer discovered the effects of microwaves on food while conducting experiments with magnetron tubes? He had chocolate in his pocket, which, due to the microwaves’ reaction, melted. The same American engineer made popcorn with the help of microwaves, using corn kernels. He set up the first microwave oven that had a cost of five thousand dollars and a height of more than a meter and a half.