Almost everyone uses a microwave, and a lot of people use it daily. Perhaps to heat the lunch, or thaw the meat for tonight’s dinner.
The technology behind a microwave is rather interesting. How can it heat up something without essentially using heat? How does a microwave oven really work? How come the microwaves heat the food but not the plate? In this article, we will find out.
Magnetic fields are created through a magnetron
In the microwave, there is a technology that creates micro waves, which is a kind of electron tube (known as a magnetron. With the help of electrons, it creates a magnetic field, which in turn generates micro waves. More specifically, when the microwave is turned on, it takes electricity and converts it into high-powered radio waves. The microwave oven generates microwaves, which fly around inside the microwave. The waves bounce back and forth inside the microwave, but when they hit the food, they don’t bounce. Instead, they find their way into the food. When the microwaves hit the food, they cause the water, sugar, and oil molecules (liquids) in the food to move. As the water molecules move, they create heat. This thermal energy warms up the other molecules, and in this way the food becomes hot. A microwave thus heats the food via radiation.
The water in the food is the reason for the heating
But what essentially ensures that the food is heated is actually the water that is found in virtually all food, because the water molecule is a dipole. The water molecule consists of one oxygen atom and two hydrogen atoms, but the bond between the three atoms results in the oxygen atom getting two free electron pairs, which causes the bond with the two hydrogen atoms to shift and the molecule becomes angled. The angle means that the center of gravity of the negative charges does not coincide with the positive ones, which is why the water molecule is a dipole.
In the microwave oven, high-frequency electromagnetic field of about 2450 MHz is generated by a microwave emitting microwaves. These powerful energy waves change the polarity of molecules back and forth between positive and negative charge millions of times per second. It causes atoms and cells to move at high speed. This violent movement in, for example, water molecules, causes (direct) heat to occur.
There is research that shows that the microwave oven reduces the nutrition of the food, but at the same time, others claim that it does not.
Of course, it also depends on how you measure. A vitamin may be left in the food, but no longer have the same bioavailability. Thus, the body cannot absorb nutrients. But there are studies that show that vitamin levels are actually lowered when the food is microwaved.
But the primary reason people use the microwave is that it is fast and convenient.
When cooking by grilling or boiling, waves of infrared frequencies are used. For example, direct heat is generated during grilling, while indirect heat is generated in a hot pot. The food is heated by a frequency, a shaking motion, and everything gets hot, even the vessel. Today we know that food cooked through cooking or oven baking (indirect heat) has more health effects than food that is grilled or fried (direct heat) which can have direct health-damaging effects.
Microwaves are not able to heat all substances, but it is only where liquid is found that the heat can be generated (as it is the water that the oven activates). No indirect heat is possible in the microwave, as hard liquid-free materials do not allow the molecules to rotate. You may have noticed that a plate does not get hot other than by the heat from the heated food in the microwave, and this is the answer why.
The result of microwave heating is a breakdown of the food at the molecular level. It can be said that microwave food is food that has been molecularly deconstructed.
The microwave oven was constructed by German scientists during the Second World War so that large quantities of food could be quickly heated for the soldiers, to support the invasion of the Soviet Union. After the war, the Russians did extensive research on microwave ovens, which resulted in them being totally banned in 1976 for health reasons, but then it was allowed again after the perestroika, but with much less radiation is in many other parts of the world.