We have all certainly used a microwave oven at least once in our lives and, regardless of the model used, there is always a metal grid on the door. But what is its purpose? It is a security systemnecessary for to shield the oven and prevent us from absorbing microwaves.
Microwave ovens in fact – as the name suggests – have an operating mechanism that is based on the production of microwaveMeaning what electromagnetic waves with a certain wavelength, which in this case is equal to approximately 12 centimeters. These radiations are excellent for heating our dishes but if the oven were not shielded we would risk absorb a part of it too: to prevent this from happening, a grid is placed on the microwave door whose shirts they are wide a few millimetersTherefore much smaller compared to the wavelength of microwaves. These, therefore, cannot pass and are reflected inside the oven itself.
Trying to make a more “everyday” comparison, it is the same thing that happens when we kick a soccer ball into a goal: the ball is too big to pass through the mesh of the net, and therefore remains inside the goal. This grid therefore has two advantages: on the one hand it avoids the dispersion of radiation, on the other it increases theenergy efficiency of the oven itself!
Before concluding, someone might ask a further question, namely: “But if there is a grid that stops the electromagnetic waves, how can we see inside the oven?”
This is possible because the visible light It has a wavelength much smaller compared to microwaves, allowing us to easily see inside the oven!
