How is the microwave heating food?

In the XX century, people first began to use the energy of electromagnetic waves to heat food. The same waves that distribute television broadcasts provide mobile communications and wireless Internet. But not all electromagnetic radiation can fry chicken.

Let’s try to figure out what is the secret. From the school curriculum, we know that the electromagnetic field affects charged particles, forcing them to move quickly and line up in strict order.

Some substances, including water, contain atoms of the opposite polarity. In water molecules, hydrogen atoms are positive particles, and oxygen atoms negative. Such a tandem of charges is called – dipole. Getting into the electric field that creates the microwave, the dipole begins to rotate and move. This process resembles the exposure of the magnet on metal chips. After some time, the molecules calm down and stop, but if the electric field will change its polarity all the time, then the dyspoly will be rebuilt all the time. While in motion, they hit each other, thus highlighting heat.

Knowing the properties of a particular substance, you can choose the frequency of an alternating electric field, optimal for its heating.

Most products used in cooking contain water. Therefore, everyday microwave ovens are as tuned as possible to its heating. For this, scientists experimentally measured the time during which water molecules are completely rebuilt under the influence of an electric field. Based on this time, the frequency is calculated optimal for heating water. It is 2450 MHz. That is, in one second, the molecule rotates about two and a half billion times.

The power of the home microwave is usually enough, to penetrate the product up to 2.5 cm. If the water is not concentrated in the warm -up dish, then accordingly, the temperature as a result will not be uniform. For example, potatoes in a soup, for a while will remain cold.