Microwaves
How does a microwave work???
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.
 If you’re unsure, check the label on the dishware.
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
Microwave Safety
 To prevent burning yourself from microwave
cooking, remember:
 Foods
can create hot containers…Use Pot Holders
 Items with an unbroken outer “skin” can explode.
Pierce them with a fork.

Items with an unbroken outer “skin” potatoes, hot dogs, apples, sausages,
chicken livers, etc.
 Lifting
the cover or plastic from the food can cause
a burn.
 Hot steam escaping can cause a burn
Cooking Controls
Time Features
Time
Cook
Convenience Features
Amount of cooking time
Starts Immediately (1,2,3,4)
Starts Immediately (1 or 2)
Time
Defrost
Power
Level
Power Level
1-10
Amount of defrost time
Popcorn
Add 30
Sec
Express Cook
Food Type 1-4
Beverage
Reheat
Cook
Food Type (1-6)
Starts Immediately
Starts Immediately
1
2
3
4
5
6
Auto
Defrost
Kitchen
Timer
Food type & Weight
Cooking Controls
Time Cook
Time Defrost
 Microwave for any time
 Defrost for a selected
up to 99 minutes.
 Press time cook
length of time.
 Press Time Defrost



Enter cooking time
Change power level if
needed
Press start


Enter defrosting time
Press start
Cooking Controls
 Power Level
 Press Time Cook OR Time Defrost




Enter cooking or defrosting time
Press Power Level
Select Desired power level 1-10
Press start
 Each power level gives you microwave energy a certain %
of the time.


Power level 7 = 70%
Power level 10 = 100%
 Lower settings cook more evenly & need less stirring or
rotating.
 Higher settings cook faster
What things should not be microwaved?
Potato Lab
 How to cook a potato in the microwave
 How to make Cheese Sauce on the stove top
Baked Potatoes- ½ potato per person. You will share with a person in your group!
• Prick a well-scrubbed potato several times with fork tines.
• Microwave on HIGH for 6 to 8 minutes, using 100 percent power.
• Turn the potato over and rearrange. Cook for additional 6 to 8 minutes until done.
Wrap in foil.
• Let stand 5 to 8 minutes to finish cooking.
Broccoli
• Wash, cut and chop broccoli into bite-size pieces.
• Put in a glass pie plate with saran wrap.
• Add 1-2 tablespoons of water.
• Cover with saran wrap.
• Cook on HIGH for 3-5 minutes or until tender crisp and done. Place in a small
bowl. Let stand, keep covered, for 5 minutes.
• Drain any excess water and mix with the cheese sauce.
Cheese Sauce
2 tbs. butter
2 tbs. plus 1 tsp. flour
Dash pepper
1 ¼ cup milk
1 ¼ cup grated cheese
•
•
•
•
•
In a pot, melt butter
Gradually, stir in flour and pepper. Mix with a wisk
Continue until the mixture is smooth.
Add milk all at once. Stir until combined.
Cook, uncovered, on HIGH for 3 to 5 minutes or until thickened and
bubbly; stirring until the sauce starts to thicken.
• Stir every 30 seconds.
• Add 1 ¼ cup grated cheese and stir until the cheese is melted.
• Then pour over the cooked broccoli and serve on top of the potato.
5 Easy Microwave Desserts you
need to Try!
VIDEO
Are microwaves Dangers?
 Video Clip