in StemSocial3 months ago

Author: @madridbg, through Power Point 2010, using public domain images.

Welcome to all those readers of the Hive community who are passionate about science-related content. In this installment, we will address the different chemical fundamentals that are present in a microwave oven, starting from the premise that it is an instrument of common use in our daily lives and where questions arise about its effect on human health.

As has been constant in my publications, this type of material will be shared with the @stemsocial community, who are trending in scientific publications on the #Hive platform.


In recent years, a series of initiatives have been developed for an ecological energy consumption, where techniques such as electrochemistry and microwave radiation have been applied in equipment commonly used in our homes.

This technology, although it arises in the 40s, its maximum expression appears at the end of the 70s when it begins its commercialization in equipment of different sizes and models that we know as microwave oven.

In this sense, microwave radiation is one of the most used, where more than 20% of the world's population applies it through the ovens we use to heat and defrost food quickly and efficiently. Where the thermal process, is carried out through electromagnetic radiation that travels in the form of waves and move in parallel in space.

Therefore, through this publication we will address the chemical fundamentals present in this technology, which is related to the dipole moments exhibited by the different elements that form the substances that make up the food.


Chemically, the atoms present in the different compounds we know, have the property of displacing their electrons according to the electronegativity of the substances involved. In this sense, the displacement can be verified through an electric field, since the molecules orient their ends according to the cathode or anode of the electric field used. That is to say, the negative charges bring the positive ones and vice versa.

Therefore, the product of the charge (Q) times the length between the charges (r) is known as dipole moment, according to the following equation. [3]

Equation 1. Representation of the dipole moment. Author: @madridbg, through PowerPoint 2010.

At the molecular level and in order to instruct the reader on the operation and mechanism of action of microwave waves, we will talk about polar substances and non-polar substances. In reference to the former, they are formed with atoms of different elements that have different electronegativity, so that the momentum charges do not cancel each other out. With regard to the latter, they do not have a dipole moment since they have the same type of atom and the charges cancel each other out.

Fig. 1. Representation of a molecule. Author: @madridbg, through PowerPoint 2010. Adapted from Chang, (2010).

Table 1. Examples of molecules and their dipole elements. Author: @madridbg, adapted from McMURRY E., John and Fay C., Robert. (2008).


Electromagnetic waves or radiations arise due to the behavior of electrons in atoms, where electric and magnetic fields interact with each other, traveling parallel in empty space or in some diffraction medium [5]. Physically waves are considered as a disturbance or vibrational disturbances that have the property of transmitting energy through a medium.

Due to wave motions, disturbances are created with the formation of crests (higher height region) and valleys (lower height region) generating parameters such as amplitude, length and frequency of the waves. Concepts that will not be handled in this topic because of the orientation that will be given to it.

Fig. 2. Representation of electromagnetic waves. Author: helder100

The amount of energy that electromagnetic waves transmit, is related to the length, since as it becomes smaller, the energy that accumulates is greater as we can see in the following image.

Fig. 3. Representation of the electromagnetic spectrum. Author: NASA


In the previous sections, we mentioned that microwave ovens, have the ability to heat and defrost food with a fast that ranges from 3 to 5 minutes according to the type of work we want it to perform.

In this sense, the technology applied in these appliances consists of different parts that are assembled as a whole and that we will describe below.

1. The magnetron, this compartment aims to generate a kinetic process in the electrons that are generated in the magnetic field, consists of a cylinder that behaves as a cathode and the walls of the same serious anode, therefore the movement of electrons is given with the cathode - anode interactions and vice versa. The speed that the electrons acquire allow to generate microwave wave that are concentrated with a frequency of 2.45 GHz.

2. The waveguide, refers to an exit tube where the waves produced by the magnetron are directed and concentrated in the compartment where we place the food.

3. The ventilated, has with function to realize a uniform distribution of the waves so that every part of the food comes in contact with this type of electromagnetic radiation.

Fig. 4. Microwave internal components. Author: natureduca

Once the internal structure of microwave ovens is known, the following question arises.

What causes food to heat up so quickly in the presence of microwave waves?

To answer this question, it is necessary to remember that microwave waves are made up of an electric field and a magnetic field. The electric field is the one that interacts with the polar molecules of the food, which mostly refers to the water present in the food.

In this sense, the molecules tend to present a rotational movement at room temperature, a movement that is accelerated by the action of microwave energy that produces a friction between the molecules, aligning the dipole moments of these and generating the heating of the same.

Another aspect that we must take into account, is that the non-polar molecules present in food, do not have the ability to absorb this type of energy so it does not affect or interrupt the action of microwaves and therefore, this can reach the different parts of our food depending on the amount of water it contains.

Fig. 5. Representation of the microwave oven. Author: EK_Song


Nowadays it is common to hear about the problems caused by microwave radiation on health, in a certain way, a direct exposure to this type of wave according to studies conducted can induce the formation of cataracts and temporary sterility in men.

However, if we focus on the technology implemented in the furnaces, we can state with certainty that the correct use of the instrument does not cause any damage to health. Beyond possible burns due to overheated food, proliferation of bacteria due to undercooking of food.

However, it is necessary to instruct the reader about the use of plastic materials in microwave ovens (polystyrene), since these substances due to heating melt and pass into the food where they indirectly reach our body and can generate the appearance of diseases.


Dear readers, through the following topic we were able to establish concrete relationships between some technological equipment (microwave oven) and its chemical basis. Likewise, we were able to know some technical aspects of one of the electromagnetic radiations that are most used nowadays, making a tour of the effects of this type of radiation on health and establishing the ideal conditions that we should consider to use this type of devices.


[1] Aradilla, D. Oliver, R. Estrany, F. (2009). The chemistry of microwave radiation. Pictelia. Técnica Industrial 284. Article: Online Access

[2] Chang, R. (2010). Química. Decima edicion. McGraw-hill Interamericana editores. ISBN: 978-607-15-0307-7.

[3] McMURRY E., John y Fay C., Robert. (2008). Química general. Quinta edición PEARSON EDUCACIÓN, México, 2009 ISBN: 978-970-26 1286-5.

[4] Ralph, H. Petrucci, William S. Harwood, E. Geoffrey Herring. (2003). QUIMICA GENERAL. Octava edición. PEARSON EDUCACIÓN. S.A., Madrid.

[5] Rahman Zamani, MD, MPH. Adapted text based on consumer information on microwave oven radiation prepared by the Food and Drug Administration, Center for Devices and Radiological Health. Article: Online Access



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