MW heating is based on a physical phenomenon generated by the interaction between electromagnetic waves and foods.
Dipole rotation and ionic conduction are the 2 most important phenomena occurring during the MW heating. With dipole rotation, when polar molecules such as water are exposed to an MW field, the rapid change in the direction of the electric field causes the water molecules to attempt to align in the direction of the electric field. As the molecules agitate, heat is generated. In ionic conduction, heat is generated because of the increase mobility of the ions caused by the exposure of them to an MW field