What is the mechanism of Microwave oven?

Microwave ovens cook with the radiation similar to radar waves. In an ordinary oven, heat first hits the outside of the food and works its way inward. But in microwave oven, radiation goes through the food, bounces off the floor or wall of the oven and goes through the food again. The radiation changes its polarity or its '+'ve and '-'ve direction several billion times a second. The rapidly oscillating microwave radiation acts on the water in food because of a special property of water, ie. water molecule has a '+'ve and '-'ve end - Oxygen and Hydrogen. Every water molecule responds to the reversal of microwave field by reversing itself, twisting back and forth billions of times a second. By the twisting water molecules rub against other molecules, they generate friction, which causes the food to heat up and cook rapidly.