How does it Work?

http://www.oddmix.com/elec/bat_nicd_varta_5099_9v100ma.html

This soup bowl works in a way that allows it to heat up over and over again. The stainless steel inside heats up with the use of two rechargeable 9-volt batteries that are connected by wires to pass a current through the metal inside of the bowl. This current is enough to heat a bowl of soup up in the same time as a conventional microwave but the benefit is that you will never burn your hand on the outside of this bowl. How can this be safe? The outside of the bowl has a barrier of rubber and plastic allowing the bowl to heat up while the outside of the bowl does not change temperature at all. This product is safe but is not recommended for children under the age of 10 because if a child touches the metal part during the heating process it could burn them.