21
MICROWAVING PRINCIPLES
Microwave energy has been used in this country to cook and reheat food since early experiments with
RADAR in World War ll. Microwaves are present in the atmosphere all the time, both naturally and
manmade sources. Manmade sources include radar, radio, television, telecommunication links and car
phones.
CONVERSION CHARTS
In a microwave oven,
electricity is converted
into microwave by the
MAGNETRON.
REFLECTION
The microwaves
bounce off the metal
walls and the metal
door screen.
TRANSMISSION
Then they pass through the
cooking containers to be
absorbed by the water
molecules in the food, all
foods contain water to a
more or lesser extent.
ABSORPTION
The microwaves cause the water molecules to
vibrate which causes FRICTION, i.e. HEAT. This
heat then cooks the food. Microwaves are also
attracted to fat and sugar particles, and foods high in
these will cook more quickly. Microwaves can only
penetrate to a depth of 1
1
/2 - 2 inches(4-5cm) and as
heat spreads through the food by conduction, just as
in a traditional oven, the food cooks from the outside
inwards.
WEIGHT MEASURES
15 g
1
/2 oz.
25 g 1 oz.
50 g 2 oz.
100 g 4 oz.
175 g 6 oz.
225 g 8 oz.
450 g 1 lb.
HOW MICROWAVES COOK FOOD
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VOLUME MEASURES
30 ml 1 fl.oz.
100 ml 3 fl.oz.
150 ml 5 fl.oz. (
1
/4 pt)
300 ml 10 fl.oz. (
1
/2 pt)
600 ml 20 fl.oz. (1pt)
SPOON MEASURES
1.25 ml
1
/4 tsp
2.5 ml
1
/2 tsp
5 ml 1 tsp
15 ml 1 tbsp
FLUID MEASUREMENTS
1 Cup = 8 fl.oz. = 240 ml
1 Pint = 16 fl.oz. (UK 20 fl.oz.) = 480 ml (UK 560 ml)
1 Quart = 32 fl.oz. (UK 40 fl.oz.) = 960 ml (UK 1120 ml)
1 Gallon = 128 fl.oz. (UK 160 fl.oz.) = 3840 ml (UK 4500 ml)
SA37X(¿ )-1B4K9S 02.9.3 11:38 AM ˘`21
