(1) Microwave ovens. When the word microwave is used, most people
probably immediately think of microwave ovens. The microwave oven has been used
for years for food preparation in restaurants and the military, but it is now readily
available for home use. The number of microwave ovens in use by conservative
estimate in 1980 was more than ten million.
(a) Microwave ovens operate like this:
1 Microwaves flip the tiny molecules that make up the food
backward and forward. This causes heat by friction.
2 In the microwave oven is a valve called a magnetron. This
valve causes microwaves to move along a waveguide and into the oven.
3 These waves swing back and forth through the food being
cooked, flipping the molecules in the food back and forth.
4 The flipping molecules in the food heat up. As the food
molecules heat up, the food is cooked.
Figure 2-3. Cooking by microwaves--the microwave oven.
Advantages of microwave cooking are:
1 Only the food is heated, not the oven walls; therefore, the oven
is easily cleaned and cooking is more efficient.
2 The food is cooked throughout rather than only from the surface
inward (as in conventional ovens).