Microwave Oven day takes place annually on 6 December. Microwave oven day commemorates the occasion when, Quite by accident, self- taught American engineer Percy Spencer discovered in 1945 a way to heat food safely with microwaves whilst working with an active radar for the company Raytheon when he noticed that a candy bar in his pocket had begun melting whilst he was near the radar. Spencer then began experimenting and deliberately attempted cooking popcorn with the microwaves and then he tried an egg. Unfortunately The egg exploded in his fellow engineer’s face! Spencer, then started experimenting with different methods of heating food safely with microwaves.
A microwave oven heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range This induces polar molecules in the food to rotate and produce thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm (1–1.5 inches) of a homogeneous, high water content food item; food is more evenly heated throughout than generally occurs in other cooking techniques.
The development of the cavity magnetron in the UK made possible the production of electromagnetic waves of a small enough wavelength (microwaves). American engineer Percy Spencer is generally credited with inventing the modern microwave oven after World War II from radar technology developed during the war. Named the “Radarange”, it was first sold in 1946. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. Sharp Corporation introduced the first microwave oven with a turntable between 1964 and 1966. The countertop microwave oven was first introduced in 1967 by the Amana Corporation. After Sharp introduced low-cost microwave ovens affordable for residential use in the late 1970s, their use spread into commercial and residential kitchens around the world. In addition to their use in cooking food, types of microwave ovens are used for heating in many industrial processes.
Since then Microwave ovens have become common kitchen appliance and are popular for reheating previously cooked foods and cooking a variety of foods. They are also useful for rapid heating of otherwise slowly prepared foodstuffs, which can easily burn or turn lumpy when cooked in conventional pans, such as hot butter, fats, chocolate or porridge. Unlike conventional ovens, microwave ovens usually do not directly brown or caramelize food, since they rarely attain the necessary temperatures to produce Maillard reactions. Exceptions occur in rare cases where the oven is used to heat frying-oil and other very oily items (such as bacon), which attain far higher temperatures than that of boiling water. However Microwave ovens have limited roles in professional cooking, because the boiling-range temperatures of a microwave will not produce the flavorful chemical reactions that frying, browning, or baking at a higher temperature will. However, additional heat sources can be added to microwave ovens.
Microwave cooking is thought to be less healthy than normal cooking although All forms of cooking Have an effect on food and nutrients, Any form of cooking will destroy some nutrients in food, but the key variables are how much water is used in the cooking, how long the food is cooked, and at what temperature. Nutrients are primarily lost by leaching into cooking water, which tends to make microwave cooking healthier, given the shorter cooking times it requires. Like other heating methods, microwaving converts vitamin B12 from an active to inactive form; the amount of conversion depends on the temperature reached, as well as the cooking time. Boiled food reaches a maximum of 100 °C (212 °F) (the boiling point of water), whereas microwaved food can get locally hotter than this, leading to faster breakdown of vitamin B12. The higher rate of loss is partially offset by the shorter cooking times required.
Spinach retains nearly all its folate when cooked in a microwave; in comparison, it loses about 77% when boiled, leaching out nutrients. Bacon cooked by microwave has significantly lower levels of carcinogenic nitrosamines than conventionally cooked bacon. Steamed vegetables tend to maintain more nutrients when microwaved than when cooked on a stovetop. Microwave blanching is 3–4 times more effective than boiled water blanching in the retaining of the water-soluble vitamins folic acid, thiamin and riboflavin, with the exception of ascorbic acid, of which 28.8% is lost (vs. 16% with boiled water blanching). Microwaving human milk at high temperatures is not recommended as it causes a marked decrease in activity of anti-infective factors.
A safety benefit of using microwave oven is that Microwave ovens heat food without getting hot themselves. Taking a pot off a stove, unless it is an induction cooktop, leaves a potentially dangerous heating element or trivet that will stay hot for some time. Likewise, when taking a casserole out of a conventional oven, one’s arms are exposed to the very hot walls of the oven. A microwave oven does not pose this problem.
Food and cookware taken out of a microwave oven are rarely much hotter than 100 °C (212 °F). Cookware used in a microwave oven is often much cooler than the food because the cookware is transparent to microwaves; the microwaves heat the food directly and the cookware is indirectly heated by the food. Food and cookware from a conventional oven, on the other hand, are the same temperature as the rest of the oven; a typical cooking temperature is 180 °C (356 °F). That means that conventional stoves and ovens can cause more serious burns.
The lower temperature of cooking (the boiling point of water) is a significant safety benefit compared to baking in the oven or frying, because it eliminates the formation of tars and char, which are carcinogenic. Microwave radiation also penetrates deeper than direct heat, so that the food is heated by its own internal water content. In contrast, direct heat can burn the surface while the inside is still cold. Pre-heating the food in a microwave oven before putting it into the grill or pan reduces the time needed to heat up the food and reduces the formation of carcinogenic char. Unlike frying and baking, microwaving does not produce acrylamide in potatoes, however unlike deep-frying, it is of only limited effectiveness in reducing glycoalkaloid (i.e. solanine) levels. Acrylamide has been found in other microwaved products like popcorn.
There are also hazards to using a Microwave oven these include the superheating of Water and other homogeneous liquids when heated in a microwave oven in a container with a smooth surface when the liquid reaches a temperature slightly above its normal boiling point without bubbles of vapour forming inside the liquid. The boiling process can start explosively when the liquid is disturbed, such as when the user takes hold of the container to remove it from the oven or while adding solid ingredients such as powdered creamer or sugar. This can result in spontaneous boiling (nucleation) which may be violent enough to eject the boiling liquid from the container and cause severe scalding.
Closed containers, such as eggs, can explode when heated in a microwave oven due to the increased pressure from steam. Intact fresh egg yolks outside the shell will also explode, as a result of superheating. Insulating plastic foams of all types generally contain closed air pockets, and are generally not recommended for use in a microwave, as the air pockets explode and the foam (which can be toxic if consumed) may melt. Not all plastics are microwave-safe, and some plastics absorb microwaves to the point that they may become dangerously hot. Products that are heated for too long can catch fire. Though this is inherent to any form of cooking, the rapid cooking and unattended nature of the use of microwave ovens results in additional hazard.
Microwaving metal objects is also dangerous as any metal or conductive object placed into the microwave will act as an antenna to some degree, resulting in an electric current. This causes the object to act as a heating element. This effect varies with the object’s shape and composition, and is sometimes utilized for cooking.
Any object containing pointed metal can create an electric arc (sparks) when microwaved. This includes cutlery, crumpled aluminium foil (though some foil used in microwaves are safe, see below), twist-ties containing metal wire, the metal wire carry-handles in paper Chinese take-out food containers, or almost any metal formed into a poorly conductive foil or thin wire; or into a pointed shape. Forks are a good example: the tines of the fork respond to the electric field by producing high concentrations of electric charge at the tips. This has the effect of exceeding the dielectric breakdown of air, about 3 megavolts per meter (3×106 V/m). The air forms a conductive plasma, which is visible as a spark. The plasma and the tines may then form a conductive loop, which may be a more effective antenna, resulting in a longer lived spark. When dielectric breakdown occurs in air, some ozone and nitrogen oxides are formed, both of which are unhealthy in large quantities.
Direct microwave exposure is also dangerous but is not generally possible, as microwaves emitted by the source in a microwave oven are confined in the oven by the material out of which the oven is constructed ovens are equipped with redundant safety interlocks, which remove power from the magnetron if the door is opened. According to the United States Food and Drug Administration’s Center for Devices and Radiological Health, a U.S. Federal Standard limits the amount of microwaves that can leak from an oven throughout its lifetime to 5 milliwatts of microwave radiation per square centimeter at approximately 5 cm (2 in) from the surface of the oven. This is far below the exposure level currently considered to be harmful to human health.
Other events occurring on 6 December
Mitten Tree Day
National Miners Day
National Gazpacho Day
National Pawnbrokers Day
Put On Your Own Shoes Day
St. Nicholas Day