Microwaves and How They Work

Microwaves are a form of high frequency radio waves similar to those used by a radio, including AM, FM and CB.

Electricity is converted into microwave energy by the magnetron tube (which is the heart of the microwave oven).

From the magnetron tube, microwave energy is transmitted to the oven cavity. The microwaves are converted to heat in the food. The microwaves enter from the outside of the food and travel through the food. Continued cooking to the centre occurs by conduction.

Although pacemakers used to be affected by microwaves (as well as by other radio waves), they are now shielded and are not bothered by these interferences. This allows people with pacemakers to sit calmly by their radio or television and cook with microwave ovens.

When the microwaves come in contact with a substance, any one or a combination of three things may occur. They can be:

1.REFLECTED

2.TRANSMITTED

3.ABSORBED

Reflection

Metal substances REFLECT microwave energy because there is no absorption and there is no heating. This is why the oven interior is either stainless steel or paint-coated steel. This ensures that the microwaves are kept inside the cavity and evenly distributed throughout the food with the help of the turntable.

Transmission

Such substances as paper, glass and plastic TRANSMIT microwave energy and do not become hot except from food. Because these substances do not reflect or absorb microwave energy, they are ideal materials for microwave cooking containers.

Absorption

Food contains moisture and will ABSORB microwave energy, which causes the moisture molecules within the food to vibrate at an incredible rate (2,450,000,000 times per second). Friction, created by vibration, produces heat energy which is conducted throughout the food.

Before Operation

Cookware and Utensil Guide

It is important to use correct containers when cooking in a microwave oven. The following will help you to make the right selection.

How to Test a Container for Safe Microwave Oven Use

Fill a 1-cup glass measure with water and place it in the microwave oven along with the container to be tested; heat one minute on HIGH. If the container is microwave oven safe, it should remain comfortably cool and the water should be hot. If the container becomes very hot, it has absorbed some microwave energy and should not be used. This test cannot be used for plastic containers.

Paper Products and Freezer Wrap

Waxed paper, paper plates, cups and napkins should not be used for heating or cooking food by Convection, Combination and Grill. Freezer wrap should not be used as it is not heat resistant and may melt. Paper towels, greaseproof paper and bake paper may be safely used for short periods of time for covering or lining.

Glass, Ceramic and China

Heat-Resistant glass cookware is invaluable in microwave cooking. Many of these items are readily available in most homes: glass jugs, mixing bowls, loaf dishes, covered casseroles, oblong baking dishes, pie plates and round or square cake dishes. Examples of this type of cookware are Pyrex® and Corningware®.

Dinnerware can be used for microwave heating. Many brands of dinnerware are microwave safe. Check the care information for reference to microwave use for dinnerware and serving pieces. If dinnerware is marked ovenproof, it frequently is safe to use in the microwave oven. However, to be sure, check by conducting a microwave dish test.

Several types of glassware and dinnerware are not recommended for use in the Microwave Oven. Do not use dishes with metallic trim or containers with metal parts. Do not use cups or mugs with glued on handles, as they may fall off with continued heating. Do not use delicate glassware. Although the glassware may be transparent to microwave energy the heat from the food may cause the glassware to crack.