How do microwave ovens work

How do microwave ovens work
The science made easy.

There are plenty of people out there who wish to know exactly how do microwave ovens work and while at first glance it may look difficult to understand it is in fact quite simple.

Let’s start with the microwaves themselves they are a form of electromagnetic waves meaning they are oscillations of electric and magnetic fields that take the form of waves. The microwaves used in microwave ovens have a wavelength of 12.2 centimeters and oscillate at a frequency of 2.45 gigahertz.

In a microwave oven the microwaves are generated from a special type of vacuum tube called a magnetron which was first invented sometime in the forties for research related to radar detection.

How do microwave ovens work in a simple form?

A microwave oven heats food by acting upon the water molecules found in any type of organic matter, the frequency the ovens use is ideal for this process. The microwaves cause the water molecules to shake and vibrate extremely fast thus creating friction by rubbing against the other molecules in the food thus heating them. This is easily explained by the fact that you cannot cook dry foods such as pasta or rice in a microwave oven unless they’re in water.

How does microwave heating affect water?

A water molecule is comprised of three atoms: two hydrogen atoms and one oxygen atom. The water molecule is what scientists call polar molecules, meaning that they arranged their electrons in such a manner that the positive charges are on one side of the molecule while the negative charges are on the other.

Since microwaves are electromagnetic waves these create constantly changing electric fields in the matter inside the microwave oven, this acts upon water molecules by making them rotate in order to minimize the force both their polar sides. Since electromagnetic waves create quickly changing electric fields, the water molecules in our food are in constant rotation to orient themselves in the opposite direction.

This is easily understood by the difference of how frozen foods heat unevenly. When water molecules are frozen they cannot move in response to electromagnetic waves so that’s why heating ice can’t be done very easily in a microwave. This is also the reason why most microwaves nowadays have a special setting for defrosting foods.

It is interesting to note that the 2.45 gigahertz frequency used by microwave ovens is the ideal one for causing water molecules to rotate at their fastest possible rate. There is also the added bonus that the frequency is not used for communication so microwave ovens do not interfere with cell phones, wireless internet, televisions and so on.

Now you may be asking yourself why exactly does the rotation of water molecules in your food heat food; well the answer has to do with the intrinsic nature of heat energy and temperature. Heat energy is the random kinetic energy of individual atoms and molecules, this means that something is hooter because the atoms and molecules it is comprised of are moving around faster than their default position.

When water molecules rotate under the action of microwaves, they bump into other molecules causing these molecules to randomly move as well and this friction motion creates heat. Microwave energy transforms the kinetic energy of the moving water molecules into heat energy by causing them to move the molecules around them.

This in a nut-shell is how and why microwaves heat up your food.

To help you more understand about how do microwave ovens work, you can take a look at this microwave oven schematic picture.