There are several misconceptions regarding microwave ovens, many of which are simply not true. In fact, one of the most abstract claims made about microwaves is that they can cause cancer. As scientists, we understand that this is not the case. Microwave ovens exploit high wavelength radiation at the lower energy region of the electromagnetic spectrum, which is not particularly dangerous. It is thus important to dispel some of the misconceptions regarding microwave ovens, especially the myths about radioactivity and poor protection.
SEATTLE, WA – SEPTEMBER 20: An “Amazonbasics Microwave,” which can be controlled by Alexa, is pictured at Amazon Headquarters shortly after being launched, on September 20, 2018, in Seattle Washington. Amazon launched more than 70 Alexa-enable products during the event. (Photo by Stephen Brashear/Getty Images)
Radioactive species are not generated in a microwave oven
Radioactivity involves the emission of radiation from spontaneous decay of unstable atomic nuclei. Energy is lost through the release of elementary particles, such as gamma-ray photons, from the nucleus or from electron shells as x-rays. Fortunately, microwave ovens do not release these high energy species, nor do they produce such high energy species. Most microwaves use a magnetron to generate either pulsed or continuous microwaves. In the magnetron, beams of electrons are made to follow curved trajectories, in vacuum tubes, through the combination of electric and magnetic fields. The consumer microwave magnetron emits 2.45 GHz microwaves. This frequency is quite low, which corresponds to low energy. What this means is microwaves do not have enough energy to remove electrons from the food being heated. What they will do is generate heat by inducing molecular vibrations, breaking hydrogen bonds, and allowing for ionic migration of free salts in an electric field.
Microwave ovens are well protected
While the microwave door might seem simple, it is actually inherently complicated. Many different components are used to form the protective door. One of those pieces is known as a choke. In a study conducted by Kusama et al., it was found that the structure of the choke derived in a finite-difference time-domain (FDTD) analysis was very similar to the experimentally designed choke structure. This structure was also found to obtain the maximum shielding effect. While there were many parameters and factors, they assessed the metal lengths (S1 and S2) and the angle (theta). They calculated the radiation power P2 exiting the choke by changing the three previously mentioned parameters. One rather interesting finding from their paper was the effect of the angle on the shielding. This portion was conducted at fixed metal lengths of 4.00 mm and 9.01mm for S1 and S2 respectively.
| Angle (theta)[Deg] | 0 | 15.52 | 26.56 | 33.69 | 45.00 | 56.31 | 63.40 | 70.56 | 90 |
| Approximate Shielding effect [dB] | 21 | 18 | 27 | 35 | 29 | 22 | 18 | 17 | 16 |
From the data, it is evident that the shielding length changed with the angle, and the optimum angle was found to be 33.69o. This theoretical structure (S1 4 mm, S2 9.01 mm, 33.69o) was found to resemble the empirical structure, and thus the choke has been designed shield effectively. Hence, the choke and other components, which reflect microwave radiation, provide apt protection and prevent the release.
Don’t believe everything you read online; Microwaves are safe. Let me know what your opinions are in the comments.
