It is estimated that over 90% of American households use a microwave oven. But how does a microwave work? This post will answer that question!
How Does a Microwave Work?
Microwaves heat food by a process known as ‘dielectric heating’. A microwave oven converts electric energy to microwave radiation. This is done in the a cavity magnetron. The non-ionizing microwave radiation is passed through the food. It is important to understand that microwave radiation is a form of electromagnetic radiation. This means that microwave radiation has an electric field. Water, fat and some other substances also have an electric charge. One side of the molecule will have a positive charge and the other side has a negative charge. Chemistry students will understand that this is due to a difference in polarity (dipole-dipole forces). Therefore, when the microwave radiation passes through the molecules will attempt to line up with the electric field of the radiation.
But how does this heat the food? Well, appliances are on alternating current (AC). Hence, the molecules will continue to reverse direction as the current alternates. The molecules will, therefore, continue to move and collide with other molecules. This movement raises the temperature of the food. By definition, temperature is the average kinetic energy (measured by how fast a molecule is moving) of a molecule. Hence, the faster they move, the hotter the temperature!
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