Answer to Question 1
Construction includes more effective washing action and energy efficient motors. There are water-saver dishwashers that use only 6 gallons. There are other advanced technology such as settings that determine the length of the wash cycle and the temperature of the water necessary to clean the dishes.
Answer to Question 2
Microwave cooking activates the molecules in food about 2 1/2 billion times per second. The friction between the molecules produces the heat.