So, let's go back to my niece's question: Can we actually destroy an oven by merely turning it on without nuking anything inside? Before I answered her, I had to bop her in the head. "Yes!" The insight is simple. The oven uses hi-freq sound waves to heat up the soup. If there's nothing to suck the heat, it will be reabsorbed by the walls of the oven and damage the magnetron. The magnetron is the internal antenna -- an extremely essential part of microwave ovens.
