Transcript icrowave.ppt

Microwaves
History of Microwaves
• In 1945, Dr. Perry Spencer, a scientist,
was working in a lab when he felt some
heat on his hand. The heat was coming
from microwaves. These were being
emitted from a nearby vacuum tube. Dr.
Spencer was curious and place a
chocolate bar near the tube. Within
seconds, the chocolate melted. That sticky
mess was the beginning of a brilliant idea
– the microwave!
Diagram of a Microwave
How Does a Microwave Work?
• The microwave oven generates electromagnetic
waves (called microwaves) which makes water
move. This motion leads to friction, and friction
leads to heating.
motion
friction
heating
How Does a Microwave Work?
• This heat starts on the outside of the food
and moves in.
• The denser the food the longer it will take
to cook.
– Water will heat faster than a burrito, because
a burrito is more dense than water.
Microwaves
• Microwaves are attracted to foods that are
high in:
sugar
fat
water
Microwave-able Containers
• Paper
• Plastic
• Glass
• Microwaveable Dishes
Non-Microwave-able Containers
• Metal
• Dishes with gold or silver on it.
Acceptable coverings for
microwave dishes:
• Paper towel – to absorb moisture,
spatters, and spills.
• Wax paper – holds in some of the
moisture
• Plastic wrap – hold in moisture
Techniques for Microwaving
• Stirring: To pull heated part of the food to
the center
• Turning over: To microwave all sides
• Rotating: Makes cooking even
• Pricking: To keep foods from exploding
• Standing Time: To allow foods to complete
its cooking by placing on the counter.
Cooking Time
• These will increase the cooking time and
standing time.
– The volume of the food
• Example: Small potatoes versus large potatoes
– The quantity or number of food
– Round containers will cook more evenly than
square containers.
Microwave Safety
• To prevent burning yourself from
microwave cooking, remember:
– Foods can create hot containers
– Items can explode (eggs, potatoes). Pierce
them with a fork.
– Lifting the cover or plastic from the food can
cause a burn.
– Hot steam escaping can cause a burn
What foods should not be
microwaved?