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115-484: Copper frying pans were used in ancient Mesopotamia . Frying pans were also known in ancient Greece , where they were called tagēnon ( Ancient Greek : τάγηνον ) and teganon (τήγανον) and Rome , where they were called patella or sartago . The word pan derives from the Old English panna . Before the introduction of the kitchen stove in the mid-19th century, a commonly used cast-iron cooking pan called

230-428: A 'spider' had a handle and three legs used to stand up in the coals and ashes of the fire. Cooking pots and pans with legless, flat bottoms were designed when cooking stoves became popular; this period of the late 19th century saw the introduction of the flat cast-iron skillet. A versatile pan that combines the best of both the sauté pan and the frying pan has higher, sloping sides that are often slightly curved. This pan

345-548: A 10 kW, 60 MHz shortwave transmitter . The Westinghouse team, led by I. F. Mouromtseff, found that foods like steaks and potatoes could be cooked in minutes. The 1937 United States patent application by Bell Laboratories states: This invention relates to heating systems for dielectric materials and the object of the invention is to heat such materials uniformly and substantially simultaneously throughout their mass. ... It has been proposed therefore to heat such materials simultaneously throughout their mass by means of

460-415: A United States patent application for Spencer's microwave cooking process, and an oven that heated food using microwave energy from a magnetron was soon placed in a Boston restaurant for testing. Another independent discovery of microwave oven technology was by British scientists, including James Lovelock , who in the 1950s used it to reanimate cryogenically frozen hamsters . In 1947, Raytheon built

575-440: A common kitchen appliance and are popular for reheating previously cooked foods and cooking a variety of foods. They rapidly heat foods which can easily burn or turn lumpy if cooked in conventional pans, such as hot butter, fats, chocolate, or porridge . Microwave ovens usually do not directly brown or caramelize food, since they rarely attain the necessary temperature to produce Maillard reactions . Exceptions occur in cases where

690-426: A complicated and extensive syllabary. A considerable amount of Babylonian literature was translated from Sumerian originals, and the language of religion and law long continued to be the old agglutinative language of Sumer. Vocabularies, grammars, and interlinear translations were compiled for the use of students, as well as commentaries on the older texts and explanations of obscure words and phrases. The characters of

805-656: A cooking power of between 600 and 1200 watts. Microwave cooking power, also referred to as output wattage, is lower than its input wattage, which is the manufacturer's listed power rating . The size of household microwave ovens can vary, but usually have an internal volume of around 20 liters (1,200 cu in; 0.71 cu ft), and external dimensions of approximately 45–60 cm (1 ft 6 in – 2 ft 0 in) wide, 35–40 cm (1 ft 2 in – 1 ft 4 in) deep and 25–35 cm (9.8 in – 1 ft 1.8 in) tall. Microwaves can be turntable or flatbed. Turntable ovens include

920-464: A countertop. (The legs usually attach to handles.) Electric frying pans are common in shapes that are unusual for 'unpowered' frying pans, notably square and rectangular. Most are designed with straighter sides than their stovetop cousins and include a lid. In this way they are a cross between a frying pan and a sauté pan. A modern electric skillet has an additional advantage over the stovetop version: heat regulation. The detachable power cord incorporates

1035-570: A glass plate or tray. Flatbed ones do not include a plate, so they have a flat and wider cavity. By position and type, US DOE classifies them as (1) countertop or (2) over the range and built-in (wall oven for a cabinet or a drawer model). A traditional microwave only has two power output levels, fully on and fully off. Intermediate heat settings are achieved using duty-cycle modulation and switch between full power and off every few seconds, with more time on for higher settings. An inverter type, however, can sustain lower temperatures for

1150-437: A higher temperature than water (the temperature they require to vaporize is higher), so inside microwave ovens they normally reach higher temperatures – sometimes much higher. This can induce temperatures in oil or fatty foods like bacon far above the boiling point of water, and high enough to induce some browning reactions, much in the manner of conventional broiling (UK: grilling) , braising, or deep fat frying. The effect

1265-580: A higher temperature, or even if the inner layer is more thermally conductive than the outer layer making it feel hotter despite having a lower temperature. In most cases, however, with uniformly structured or reasonably homogeneous food item, microwaves are absorbed in the outer layers of the item at a similar level to that of the inner layers. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast with broiling / grilling (infrared) or convection heating methods which thinly deposit heat at

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1380-635: A language of the Zagros possibly related to the Hurro-Urartuan language family , is attested in personal names, rivers and mountains and in various crafts. Akkadian came to be the dominant language during the Akkadian Empire and the Assyrian empires, but Sumerian was retained for administrative, religious, literary and scientific purposes. Different varieties of Akkadian were used until

1495-417: A large number of copper pans are sold with a tin lining which can be replaced when it wears out. Cast iron pans are used because although they do not conduct heat very evenly, they do retain it quite well, making them useful for searing meats and vegetables. Carbon steel cookware is used because over time it can develop a highly nonstick patina of polymerized oil called seasoning useful for cooking protein that

1610-533: A lengthy duration without having to switch itself off and on repeatedly. Apart from offering superior cooking ability, these microwaves are generally more energy-efficient. As of 2020 , the majority of countertop microwave ovens (regardless of brand) sold in the United States were manufactured by the Midea Group . Domestic microwave ovens are typically marked with the microwave-safe symbol, next to

1725-409: A less expensive re-engineered magnetron. Several other companies joined in the market, and for a time most systems were built by defence contractors, who were most familiar with the magnetron. Litton was particularly well known in the restaurant business. While uncommon today, combination microwave-ranges were offered by major appliance manufacturers through much of the 1970s as a natural progression of

1840-453: A microwave oven in 1994, but that number had increased to 65% by 2004. Adoption has been slower in less-developed countries , as households with disposable income concentrate on more important household appliances like refrigerators and ovens. In India , for example, only about 5% of households owned a microwave oven in 2013, well behind refrigerators at 31% ownership. However, microwave ovens are gaining popularity. In Russia, for example,

1955-457: A microwave oven, up from only about 1% in 1971; the U.S. Bureau of Labor Statistics reported that over 90% of American households owned a microwave oven in 1997. In Australia, a 2008 market research study found that 95% of kitchens contained a microwave oven and that 83% of them were used daily. In Canada, fewer than 5% of households had a microwave oven in 1979, but more than 88% of households owned one by 1998. In France, 40% of households owned

2070-534: A motor driven mode stirrer in the top of the oven cavity rotated allowing the food to remain stationary. In the 1960s, Litton bought Studebaker 's Franklin Manufacturing assets, which had been manufacturing magnetrons and building and selling microwave ovens similar to the Radarange. Litton developed a new configuration of the microwave oven: the short, wide shape that is now common. The magnetron feed

2185-488: A patient could not be cured physically, the Babylonian physicians often relied on exorcism to cleanse the patient from any curses . Esagil-kin-apli's Diagnostic Handbook was based on a logical set of axioms and assumptions, including the modern view that through the examination and inspection of the symptoms of a patient, it is possible to determine the patient's disease , its aetiology, its future development, and

2300-554: A precursor to the Socratic method . The Ionian philosopher Thales was influenced by Babylonian cosmological ideas. Ancient Mesopotamians had ceremonies each month. The theme of the rituals and festivals for each month was determined by at least six important factors: Some songs were written for the gods but many were written to describe important events. Although music and songs amused kings , they were also enjoyed by ordinary people who liked to sing and dance in their homes or in

2415-499: A process known as dielectric heating . These molecules have a partial positive charge at one end and a partial negative charge at the other. In an alternating electric field, they will constantly spin around as they continually try to align themselves with the electric field. This can happen over a wide range of frequencies. The electric field's energy is absorbed by the dipole molecules as rotational energy. Then they hit non-dipole molecules, making them move faster as well. This energy

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2530-425: A rapidly alternating electric field. The invention of the cavity magnetron made possible the production of electromagnetic waves of a small enough wavelength ( microwaves ). The cavity magnetron was a crucial component in the development of short wavelength radar during World War II . In 1937–1940, a multi-cavity magnetron was built by British physicist Sir John Turton Randall, FRSE and coworkers, for

2645-761: A recent hypothesis, the Archimedes' screw may have been used by Sennacherib, King of Assyria, for the water systems at the Hanging Gardens of Babylon and Nineveh in the 7th century BC, although mainstream scholarship holds it to be a Greek invention of later times. Later, during the Parthian or Sasanian periods, the Baghdad Battery , which may have been the world's first battery, was created in Mesopotamia. The Ancient Mesopotamian religion

2760-567: A sacred, ceremonial, literary, and scientific language in Mesopotamia until the 1st century AD. Libraries were extant in towns and temples during the Babylonian Empire. An old Sumerian proverb averred that "he who would excel in the school of the scribes must rise with the dawn." Women as well as men learned to read and write, and for the Semitic Babylonians, this involved knowledge of the extinct Sumerian language, and

2875-415: A table of Pythagorean triples and represents some of the most advanced mathematics prior to Greek mathematics. From Sumerian times, temple priesthoods had attempted to associate current events with certain positions of the planets and stars. This continued to Assyrian times, when Limmu lists were created as a year by year association of events with planetary positions, which, when they have survived to

2990-469: A thermostatic control for maintaining the desired temperature. With the perfection of the thermostatic control, the electric skillet became a popular kitchen appliance. Although it largely has been supplanted by the microwave oven , it is still in use in many kitchens. Mesopotamia Mesopotamia is a historical region of West Asia situated within the Tigris–Euphrates river system , in

3105-499: A turntable between 1964 and 1966. The countertop microwave oven was introduced in 1967 by the Amana Corporation . After microwave ovens became affordable for residential use in the late 1970s, their use spread into commercial and residential kitchens around the world, and prices fell rapidly during the 1980s. In addition to cooking food, microwave ovens are used for heating in many industrial processes. Microwave ovens are

3220-519: A vast mountainous region. Overland routes in Mesopotamia usually follow the Euphrates because the banks of the Tigris are frequently steep and difficult. The climate of the region is semi-arid with a vast desert expanse in the north which gives way to a 15,000-square-kilometre (5,800 sq mi) region of marshes, lagoons, mudflats, and reed banks in the south. In the extreme south, the Euphrates and

3335-453: A wavelength that is small relative to the cavity (as in a modern microwave oven) is due to "far-field" effects that are due to classical electromagnetic radiation that describes freely propagating light and microwaves suitably far from their source. Nevertheless, the primary heating effect of all types of electromagnetic fields at both radio and microwave frequencies occurs via the dielectric heating effect, as polarized molecules are affected by

3450-595: Is an-ki , which refers to the god An and the goddess Ki . Their son was Enlil, the air god. They believed that Enlil was the most powerful god. He was the chief god of the pantheon . The numerous civilizations of the area influenced the Abrahamic religions , especially the Hebrew Bible . Its cultural values and literary influence are especially evident in the Book of Genesis . Giorgio Buccellati believes that

3565-414: Is a composite product, although it is probable that some of the stories are artificially attached to the central figure. Mesopotamian mathematics and science was based on a sexagesimal (base 60) numeral system . This is the source of the 60-minute hour, the 24-hour day, and the 360- degree circle. The Sumerian calendar was lunisolar, with three seven-day weeks of a lunar month. This form of mathematics

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3680-469: Is accurate to about six decimal digits, and is the closest possible three-place sexagesimal representation of √ 2 : The Babylonians were not interested in exact solutions, but rather approximations, and so they would commonly use linear interpolation to approximate intermediate values. One of the most famous tablets is the Plimpton 322 tablet , created around 1900–1600 BC, which gives

3795-668: Is called a sauteuse (literally a sauté pan in the female gender), an evasée (denoting a pan with sloping sides), or a fait-tout (literally "does everything"). Most professional kitchens have several of these utensils in varying sizes. A "rappie pan" is a pan used to make rappie pie , an Acadian potato dish. The pan is made from aluminum or stainless steel . Traditionally, frying pans were made of cast iron , carbon steel or copper lined with tin, for their different qualities and properties. Copper pans are highly thermally conductive, making them useful for evenly sautéing. However, they are also highly reactive with most foods, so today

3910-597: Is compatible with ergodic axioms. Logic was employed to some extent in Babylonian astronomy and medicine. Babylonian thought had a considerable influence on early Ancient Greek and Hellenistic philosophy . In particular, the Babylonian text Dialogue of Pessimism contains similarities to the agonistic thought of the Sophists , the Heraclitean doctrine of dialectic , and the dialogs of Plato , as well as

4025-476: Is fairly uniform in the outer 25–38 mm (1–1.5 inches) of a homogeneous , high-water-content food item. The development of the cavity magnetron in the United Kingdom made possible the production of electromagnetic waves of a small enough wavelength ( microwaves ) to efficiently heat up water molecules. American electrical engineer Percy Spencer is generally credited with developing and patenting

4140-429: Is glass, which can exhibit thermal runaway in a microwave oven to the point of melting if preheated. Additionally, microwaves can melt certain types of rocks, producing small quantities of molten rock. Some ceramics can also be melted, and may even become clear upon cooling. Thermal runaway is more typical of electrically conductive liquids such as salty water. Another misconception is that microwave ovens cook food "from

4255-408: Is most often noticed by consumers from unexpected damage to plastic containers when microwaving foods high in sugar, starch, or fat generates higher temperatures. Foods high in water content and with little oil rarely exceed the boiling temperature of water and do not damage plastic. Cookware must be transparent to microwaves. Conductive cookware, such as metal pots, reflects microwaves, and prevents

4370-407: Is prone to stick, such as fish and eggs. While all of these materials are still commonly used in professional kitchens, many modern materials have supplanted them in the consumer market. Nowadays, most frying pans are now made from metals such as aluminium or stainless steel . The materials and construction method used in modern frying pans vary greatly and some typical materials include: A coating

4485-400: Is shared deeper into the substance as molecular rotations, vibrations or other movement signifying an increase in the temperature of the food. Once the electrical field's energy is initially absorbed, heat will gradually spread through the object similarly to any other heat transfer by contact with a hotter body. Microwave heating is more efficient on liquid water than on frozen water, where

4600-465: Is sometimes applied to the surface of the pan to make it non-stick . Frying pans made from bare cast iron or carbon steel can also gain non-stick properties through seasoning and use. A process for bonding Teflon to chemically roughened aluminium was patented in France by Marc Gregoire in 1954. In 1956 he formed a company to market non-stick cookware under the " Tefal " brand name. The durability of

4715-541: Is that they should be in one of the industrial, scientific, and medical (ISM) frequency bands set aside for unlicensed purposes. For household purposes, 2.45 GHz has the advantage over 915 MHz in that 915 MHz is only an ISM band in some countries ( ITU Region 2) while 2.45 GHz is available worldwide. Three additional ISM bands exist in the microwave frequencies, but are not used for microwave cooking. Two of them are centered on 5.8 GHz and 24.125 GHz, but are not used for microwave cooking because of

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4830-404: Is to be incorporated in a later step such as a pan sauce. Since little or no residue can stick to the surface, the sauce will fail for lack of its primary flavouring agent. An electric frying pan or electric skillet incorporates an electric heating element into the frying pan itself and so can function independently off of a cooking stove . Accordingly, it has heat-insulated legs for standing on

4945-421: Is uncertain. The Babylonian development of methods for predicting the motions of the planets is considered to be a major episode in the history of astronomy . The only Greek-Babylonian astronomer known to have supported a heliocentric model of planetary motion was Seleucus of Seleucia (b. 190 BC). Seleucus is known from the writings of Plutarch . He supported Aristarchus of Samos' heliocentric theory where

5060-674: The Earth rotated around its own axis which in turn revolved around the Sun . According to Plutarch , Seleucus even proved the heliocentric system, but it is not known what arguments he used, except that he correctly theorized on tides as a result of the Moon's attraction. Babylonian astronomy served as the basis for much of Greek , classical Indian , Sassanian, Byzantine , Syrian , medieval Islamic , Central Asian , and Western European astronomy. The oldest Babylonian texts on medicine date back to

5175-449: The ISM (industrial, scientific, medical) bands , which are otherwise used for communication amongst devices that do not need a license to operate, so they do not interfere with other vital radio services. It is a common misconception that microwave ovens heat food by operating at a special resonance of water molecules in the food. Instead, microwave ovens heat by causing molecules to spin under

5290-613: The Jazira , is the area between the Euphrates and the Tigris from their sources down to Baghdad . Lower Mesopotamia is the area from Baghdad to the Persian Gulf and includes Kuwait and parts of western Iran. In modern academic usage, the term Mesopotamia often also has a chronological connotation. It is usually used to designate the area until the Muslim conquests , with names like Syria , Jazira , and Iraq being used to describe

5405-684: The Neo-Assyrian Empire asserted control over much of the ancient Near East. Subsequently, the Babylonians, who had long been overshadowed by Assyria, seized power , dominating the region for a century as the final independent Mesopotamian realm until the modern era. In 539 BC, Mesopotamia was conquered by the Achaemenid Empire . The area was next conquered by Alexander the Great in 332 BC. After his death, it became part of

5520-650: The Old Babylonian period in the first half of the 2nd millennium BC . The most extensive Babylonian medical text, however, is the Diagnostic Handbook written by the ummânū , or chief scholar, Esagil-kin-apli of Borsippa , during the reign of the Babylonian king Adad-apla-iddina (1069–1046 BC). Along with contemporary Egyptian medicine , the Babylonians introduced the concepts of diagnosis , prognosis , physical examination , enemas , and prescriptions . The Diagnostic Handbook introduced

5635-631: The United States Department of Energy require less than 1 watt, or approximately 9 kWh per year, of standby power for most types of microwave ovens. A microwave oven generally consists of: In most ovens, the magnetron is driven by a linear transformer which can only feasibly be switched completely on or off. (One variant of the GE Spacemaker had two taps on the transformer primary, for high and low power modes.) Usually choice of power level does not affect intensity of

5750-402: The fall of Babylon in 539 BC. The rise of empires, beginning with Sargon of Akkad around 2350 BC, characterized the subsequent 2,000 years of Mesopotamian history, marked by the succession of kingdoms and empires such as the Akkadian Empire . The early second millennium BC saw the polarization of Mesopotamian society into Assyria in the north and Babylonia in the south. From 900 to 612 BC,

5865-438: The marketplaces . Songs were sung to children who passed them on to their children. Thus songs were passed on through many generations as an oral tradition until writing was more universal. These songs provided a means of passing on through the centuries highly important information about historical events. Hunting was popular among Assyrian kings. Boxing and wrestling feature frequently in art, and some form of polo

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5980-407: The É , a temple dedicated to the goddess Inanna at Uruk, from a building labeled as Temple C by its excavators. The early logographic system of cuneiform script took many years to master. Thus, only a limited number of individuals were hired as scribes to be trained in its use. It was not until the widespread use of a syllabic script was adopted under Sargon's rule that significant portions of

6095-419: The "Radarange", the first commercially available microwave oven. It was almost 1.8 metres (5 ft 11 in) tall, weighed 340 kilograms (750 lb) and cost about US$ 5,000 ($ 68,000 in 2023 dollars) each. It consumed 3 kilowatts, about three times as much as today's microwave ovens, and was water-cooled. The name was the winning entry in an employee contest. An early Radarange was installed (and remains) in

6210-701: The (two) rivers") comes from the ancient Greek root words μέσος ( mesos , 'middle') and ποταμός ( potamos , 'river') and translates to '(land) between rivers', likely being a calque of the older Aramaic term, with the Aramaic term itself likely being a calque of the Akkadian birit narim . It is used throughout the Greek Septuagint ( c.  250 BC ) to translate the Hebrew and Aramaic equivalent Naharaim . An even earlier Greek usage of

6325-830: The 7th century Muslim conquest of Persia of the Sasanian Empire and the Muslim conquest of the Levant from the Byzantines. A number of primarily neo-Assyrian and Christian native Mesopotamian states existed between the 1st century BC and 3rd century AD, including Adiabene , Osroene , and Hatra . The regional toponym Mesopotamia ( / ˌ m ɛ s ə p ə ˈ t eɪ m i ə / , Ancient Greek : Μεσοποταμία '[land] between rivers'; Arabic : بِلَاد ٱلرَّافِدَيْن Bilād ar-Rāfidayn or بَيْن ٱلنَّهْرَيْن Bayn an-Nahrayn ; Persian : میان‌رودان miyân rudân ; Syriac : ܒܝܬ ܢܗܪ̈ܝܢ Beth Nahrain "(land) between

6440-540: The 8,000-year-old remains of early farmers found at an ancient graveyard in Germany . They compared the genetic signatures to those of modern populations and found similarities with the DNA of people living in today's Turkey and Iraq . The earliest language written in Mesopotamia was Sumerian , an agglutinative language isolate . Along with Sumerian, Semitic languages were also spoken in early Mesopotamia. Subartuan ,

6555-670: The British and American military radar installations in World War II. A higher-powered microwave generator that worked at shorter wavelengths was needed, and in 1940, at the University of Birmingham in England, Randall and Harry Boot produced a working prototype. They invented a valve that could produce pulses of microwave radio energy at a wavelength of 10 cm, an unprecedented discovery. Sir Henry Tizard traveled to

6670-823: The Greek Seleucid Empire . Around 150 BC, Mesopotamia was under the control of the Parthian Empire . It became a battleground between the Romans and Parthians, with western parts of the region coming under ephemeral Roman control. In 226 AD, the eastern regions of Mesopotamia fell to the Sassanid Persians . The division of the region between the Roman Byzantine Empire from 395 AD and the Sassanid Empire lasted until

6785-473: The Mesopotamian population became literate. Massive archives of texts were recovered from the archaeological contexts of Old Babylonian scribal schools, through which literacy was disseminated. Akkadian gradually replaced Sumerian as the spoken language of Mesopotamia somewhere around the turn of the 3rd and the 2nd millennium BC. The exact dating being a matter of debate. Sumerian continued to be used as

6900-472: The Tigris unite and empty into the Persian Gulf . The arid environment ranges from the northern areas of rain-fed agriculture to the south where irrigation of agriculture is essential. This irrigation is aided by a high water table and by melting snows from the high peaks of the northern Zagros Mountains and from the Armenian Highlands, the source of the Tigris and Euphrates Rivers that give

7015-783: The US in late September 1940 to offer Britain's most valuable technical secrets including the cavity magnetron in exchange for US financial and industrial support (see Tizard Mission ). An early 6 kW version, built in England by the General Electric Company Research Laboratories, Wembley , London, was given to the U.S. government in September 1940. The cavity magnetron was later described by American historian James Phinney Baxter III as "[t]he most valuable cargo ever brought to our shores". Contracts were awarded to Raytheon and other companies for

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7130-517: The additional component cost could better be absorbed compared with countertop units where pricing was increasingly market-sensitive. By 1972, Litton (Litton Atherton Division, Minneapolis) introduced two new microwave ovens, priced at $ 349 and $ 399, to tap into the market estimated at $ 750 million by 1976, according to Robert I Bruder, president of the division. While prices remained high, new features continued to be added to home models. Amana introduced automatic defrost in 1974 on their RR-4D model, and

7245-556: The ancient history of lower Mesopotamia—commenced in the early-third millennium BC with cuneiform records of early dynastic kings. This entire history ends with either the arrival of the Achaemenid Empire in the late 6th century BC or with the Muslim conquest and the establishment of the Caliphate in the late 7th century AD, from which point the region came to be known as Iraq . In the long span of this period, Mesopotamia housed some of

7360-442: The average residential microwave oven consumes only 72 kWh per year. Globally, microwave ovens used an estimated 77 TWh per year in 2018, or 0.3% of global electricity generation. A 2000 study by Lawrence Berkeley National Laboratory found that the average microwave drew almost 3 watts of standby power when not being used, which would total approximately 26 kWh per year. New efficiency standards imposed in 2016 by

7475-410: The chances of the patient's recovery. Esagil-kin-apli discovered a variety of illnesses and diseases and described their symptoms in his Diagnostic Handbook . These include the symptoms for many varieties of epilepsy and related ailments along with their diagnosis and prognosis. Some treatments used were likely based off the known characteristics of the ingredients used. The others were based on

7590-729: The city of Eridu , the Akkadian kingdoms, the Third Dynasty of Ur , and the various Assyrian empires. Some of the important historical Mesopotamian leaders were Ur-Nammu (king of Ur), Sargon of Akkad (who established the Akkadian Empire), Hammurabi (who established the Old Babylonian state), Ashur-uballit I and Tiglath-Pileser I (who established the Assyrian Empire). Scientists analysed DNA from

7705-614: The cultural mix. Periodic breakdowns in the cultural system have occurred for a number of reasons. The demands for labor has from time to time led to population increases that push the limits of the ecological carrying capacity , and should a period of climatic instability ensue, collapsing central government and declining populations can occur. Alternatively, military vulnerability to invasion from marginal hill tribes or nomadic pastoralists has led to periods of trade collapse and neglect of irrigation systems. Equally, centripetal tendencies amongst city-states have meant that central authority over

7820-421: The cycles of the moon. They divided the year into two seasons: summer and winter. The origins of astronomy as well as astrology date from this time. During the 8th and 7th centuries BC, Babylonian astronomers developed a new approach to astronomy. They began studying philosophy dealing with the ideal nature of the early universe and began employing an internal logic within their predictive planetary systems. This

7935-428: The device's approximate IEC 60705 output power rating, in watts (typically either: 600W, 700W, 800W, 900W, 1000W), and a voluntary Heating Category (A-E). A microwave oven heats food by passing microwave radiation through it. Microwaves are a form of non-ionizing electromagnetic radiation with a frequency in the so-called microwave region (300 MHz to 300 GHz). Microwave ovens use frequencies in one of

8050-572: The dielectric loss produced in them when they are subjected to a high voltage, high frequency field. However, lower-frequency dielectric heating , as described in the aforementioned patent, is (like induction heating ) an electromagnetic heating effect, the result of the so-called near-field effects that exist in an electromagnetic cavity that is small compared with the wavelength of the electromagnetic field. This patent proposed radio frequency heating, at 10 to 20 megahertz (wavelength 30 to 15 meters, respectively). Heating from microwaves that have

8165-573: The dipole moments of their hydroxyl groups or ester groups . Microwave heating is less efficient on fats and sugars than on water because they have a smaller molecular dipole moment . Although fats and sugar typically absorb energy less efficiently than water, paradoxically their temperatures rise faster and higher than water when cooking: Fats and oils require less energy delivered per gram of material to raise their temperature by 1 °C than does water (they have lower specific heat capacity ) and they begin cooling off by "boiling" only after reaching

8280-401: The early coatings was initially poor, but improvements in manufacturing have made these products a kitchen standard. The surface is not as tough as metal and the use of metal utensils (e.g. spatulas ) can permanently mar the coating and degrade its non-stick property. For some cooking preparations a non-stick frying pan is inappropriate, especially for deglazing , where the residue of browning

8395-478: The end of the Neo-Babylonian period. Old Aramaic , which had already become common in Mesopotamia, then became the official provincial administration language of first the Neo-Assyrian Empire , and then the Achaemenid Empire : the official lect is called Imperial Aramaic . Akkadian fell into disuse, but both it and Sumerian were still used in temples for some centuries. The last Akkadian texts date from

8510-452: The first microwave oven with a turntable, an alternative means to promote more even heating of food. In 1965, Raytheon, looking to expand their Radarange technology into the home market, acquired Amana to provide more manufacturing capability. In 1967, they introduced the first popular home model, the countertop Radarange, at a price of US$ 495 ($ 5,000 in 2023 dollars). Unlike the Sharp models,

8625-454: The food surface. Penetration depth of microwaves depends on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating deeper. In use, microwave ovens can be as low as 50% efficient at converting electricity into microwaves, but energy efficient models can exceed 64% efficiency. Stovetop cooking is 40-90% efficient depending on the type of appliance used. Because they are used fairly infrequently,

8740-443: The form of a convection microwave oven. The exploitation of high-frequency radio waves for heating substances was made possible by the development of vacuum tube radio transmitters around 1920. By 1930 the application of short waves to heat human tissue had developed into the medical therapy of diathermy . At the 1933 Chicago World's Fair , Westinghouse demonstrated the cooking of foods between two metal plates attached to

8855-860: The galley of the nuclear-powered passenger/cargo ship NS Savannah . An early commercial model introduced in 1954 consumed 1.6 kilowatts and sold for US$ 2,000 to US$ 3,000 ($ 23,000 to $ 34,000 in 2023 dollars). Raytheon licensed its technology to the Tappan Stove company of Mansfield, Ohio in 1952. Under contract to Whirlpool, Westinghouse, and other major appliance manufacturers looking to add matching microwave ovens to their conventional oven line, Tappan produced several variations of their built-in model from roughly 1955 to 1960. Due to maintenance (some units were water-cooled), in-built requirement, and cost—US$ 1,295 ($ 15,000 in 2023 dollars)—sales were limited. Japan's Sharp Corporation began manufacturing microwave ovens in 1961. Between 1964 and 1966, Sharp introduced

8970-495: The influence of a constantly changing electric field, usually in the microwave frequencies range, and a higher wattage power of the microwave oven results in faster cooking times. Typically, consumer ovens work around a nominal 2.45  gigahertz (GHz) – a wavelength of 12.2 centimetres (4.80 in) in the 2.4 GHz to 2.5 GHz ISM band – while large industrial / commercial ovens often use 915  megahertz (MHz) – 32.8 centimetres (12.9 in). Among other differences,

9085-416: The inside out", meaning from the center of the entire mass of food outwards. This idea arises from heating behavior seen if an absorbent layer of water lies beneath a less absorbent drier layer at the surface of a food; in this case, the deposition of heat energy inside a food can exceed that on its surface. This can also occur if the inner layer has a lower heat capacity than the outer layer causing it to reach

9200-402: The invention of the wheel , the planting of the first cereal crops , the development of cursive script, mathematics , astronomy , and agriculture ". It is recognised as the cradle of some of the world's earliest civilizations. The Sumerians and Akkadians , each originating from different areas, dominated Mesopotamia from the beginning of recorded history ( c.  3100 BC ) to

9315-465: The late 1st century AD. Early in Mesopotamia's history, around the mid-4th millennium BC, cuneiform was invented for the Sumerian language. Cuneiform literally means "wedge-shaped", due to the triangular tip of the stylus used for impressing signs on wet clay. The standardized form of each cuneiform sign appears to have been developed from pictograms . The earliest texts, 7 archaic tablets, come from

9430-405: The longer wavelength of a commercial microwave oven allows the initial heating effects to begin deeper within the food or liquid, and therefore become evenly spread within its bulk sooner, as well as raising the temperature deep within the food more quickly. A microwave oven takes advantage of the electric dipole structure of water molecules , fats, and many other substances in the food, using

9545-443: The mass production of the cavity magnetron. In 1945, the heating effect of a high-power microwave beam was independently and accidentally discovered by Percy Spencer , an American self-taught engineer from Howland, Maine . Employed by Raytheon at the time, he noticed that microwaves from an active radar set he was working on started to melt a Mr. Goodbar candy bar he had in his pocket. The first food deliberately cooked by Spencer

9660-472: The methods of therapy and aetiology and the use of empiricism , logic , and rationality in diagnosis, prognosis and therapy. The text contains a list of medical symptoms and often detailed empirical observations along with logical rules used in combining observed symptoms on the body of a patient with its diagnosis and prognosis. The symptoms and diseases of a patient were treated through therapeutic means such as bandages , creams and pills . If

9775-528: The microwave radiation; instead, the magnetron is cycled on and off every few seconds, thus altering the large scale duty cycle . Newer models use inverter power supplies that use pulse-width modulation to provide effectively continuous heating at reduced power settings, so that foods are heated more evenly at a given power level and can be heated more quickly without being damaged by uneven heating. The microwave frequencies used in microwave ovens are chosen based on regulatory and cost constraints. The first

9890-572: The microwaves from reaching the food. Cookware made of materials with high electrical permittivity will absorb microwaves, resulting in the cookware heating rather than the food. Cookware made of melamine resin is a common type of cookware that will heat in a microwave oven, reducing the effectiveness of the microwave oven and creating a hazard from burns or shattered cookware. Microwave heating can cause localized thermal runaways in some materials with low thermal conductivity which also have dielectric constants that increase with temperature. An example

10005-452: The movement of molecules is more restricted. Defrosting is done at a low power setting, allowing time for conduction to carry heat to still frozen parts of food. Dielectric heating of liquid water is also temperature-dependent: At 0 °C, dielectric loss is greatest at a field frequency of about 10 GHz, and for higher water temperatures at higher field frequencies. Sugars and triglycerides (fats and oils) absorb microwaves due to

10120-530: The name Mesopotamia is evident from The Anabasis of Alexander , which was written in the late 2nd century AD but specifically refers to sources from the time of Alexander the Great . In the Anabasis , Mesopotamia was used to designate the land east of the Euphrates in north Syria . The Akkadian term biritum/birit narim corresponded to a similar geographical concept. Later, the term Mesopotamia

10235-590: The northern part of the Fertile Crescent . Today, Mesopotamia is known as present-day Iraq . In the broader sense, the historical region of Mesopotamia also includes parts of present-day Iran , Turkey , Syria and Kuwait . Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. It has been identified as having "inspired some of the most important developments in human history, including

10350-610: The number of households with a microwave oven grew from almost 24% in 2002 to almost 40% in 2008. Almost twice as many households in South Africa owned microwave ovens in 2008 (38.7%) as in 2002 (19.8%). Microwave oven ownership in Vietnam in 2008 was at 16% of households, versus 30% ownership of refrigerators; this rate was up significantly from 6.7% microwave oven ownership in 2002, with 14% ownership for refrigerators that year. Consumer household microwave ovens usually come with

10465-420: The origins of philosophy can be traced back to early Mesopotamian wisdom , which embodied certain philosophies of life, particularly ethics , in the forms of dialectic , dialogues , epic poetry , folklore , hymns , lyrics , prose works, and proverbs . Babylonian reason and rationality developed beyond empirical observation. Babylonian thought was also based on an open-systems ontology which

10580-444: The oven is used to heat frying-oil and other oily items (such as bacon), which attain far higher temperatures than that of boiling water. Microwave ovens have a limited role in professional cooking, because the boiling-range temperatures of a microwave oven do not produce the flavorful chemical reactions that frying, browning, or baking at a higher temperature produces. However, such high heat sources can be added to microwave ovens in

10695-402: The present day, allow accurate associations of relative with absolute dating for establishing the history of Mesopotamia. The Babylonian astronomers were very adept at mathematics and could predict eclipses and solstices . Scholars thought that everything had some purpose in astronomy. Most of these related to religion and omens. Mesopotamian astronomers worked out a 12-month calendar based on

10810-425: The region after that date. It has been argued that these later euphemisms are Eurocentric terms attributed to the region in the midst of various 19th-century Western encroachments. Mesopotamia encompasses the land between the Euphrates and Tigris rivers, both of which have their headwaters in the neighboring Armenian highlands . Both rivers are fed by numerous tributaries, and the entire river system drains

10925-441: The region its name. The usefulness of irrigation depends upon the ability to mobilize sufficient labor for the construction and maintenance of canals, and this, from the earliest period, has assisted the development of urban settlements and centralized systems of political authority. Agriculture throughout the region has been supplemented by nomadic pastoralism, where tent-dwelling nomads herded sheep and goats (and later camels) from

11040-406: The rim of the door, choke connections on the door edges act like metal-to-metal contact, at the frequency of the microwaves, to prevent leakage. The oven door usually has a window for easy viewing, with a layer of conductive mesh some distance from the outer panel to maintain the shielding. Because the size of the perforations in the mesh is much less than the microwaves' wavelength (12.2 cm for

11155-461: The river pastures in the dry summer months, out into seasonal grazing lands on the desert fringe in the wet winter season. The area is generally lacking in building stone, precious metals, and timber, and so historically has relied upon long-distance trade of agricultural products to secure these items from outlying areas. In the marshlands to the south of the area, a complex water-borne fishing culture has existed since prehistoric times and has added to

11270-538: The syllabary were all arranged and named, and elaborate lists were drawn up. Many Babylonian literary works are still studied today. One of the most famous of these was the Epic of Gilgamesh , in twelve books, translated from the original Sumerian by a certain Sîn-lēqi-unninni , and arranged upon an astronomical principle. Each division contains the story of a single adventure in the career of Gilgamesh . The whole story

11385-550: The symbolic qualities. Mesopotamian people invented many technologies including metal and copper-working, glass and lamp making, textile weaving, flood control , water storage, and irrigation. They were also one of the first Bronze Age societies in the world. They developed from copper, bronze, and gold on to iron. Palaces were decorated with hundreds of kilograms of these very expensive metals. Also, copper, bronze, and iron were used for armor as well as for different weapons such as swords, daggers, spears, and maces . According to

11500-434: The technology. Both Tappan and General Electric offered units that appeared to be conventional stove top/oven ranges, but included microwave capability in the conventional oven cavity. Such ranges were attractive to consumers since both microwave energy and conventional heating elements could be used simultaneously to speed cooking, and there was no loss of countertop space. The proposition was also attractive to manufacturers as

11615-406: The usual 2.45 GHz), microwave radiation cannot pass through the door, while visible light (with its much shorter wavelength) can. Modern microwave ovens use either an analog dial-type timer or a digital control panel for operation. Control panels feature an LED , LCD or vacuum fluorescent display, buttons for entering the cook time and a power level selection feature. A defrost option

11730-444: The very high cost of power generation at these frequencies. The third, centered on 433.92 MHz, is a narrow band that would require expensive equipment to generate sufficient power without creating interference outside the band, and is only available in some countries. The cooking chamber is similar to a Faraday cage to prevent the waves from coming out of the oven. Even though there is no continuous metal-to-metal contact around

11845-418: The volume of the frustum of a cone or a square pyramid was incorrectly taken as the product of the height and half the sum of the bases. Also, there was a recent discovery in which a tablet used π as 25/8 (3.125 instead of 3.14159~). The Babylonians are also known for the Babylonian mile, which was a measure of distance equal to about seven modern miles (11 km). This measurement for distances eventually

11960-704: The whole region, when imposed, has tended to be ephemeral, and localism has fragmented power into tribal or smaller regional units. These trends have continued to the present day in Iraq. The prehistory of the Ancient Near East begins in the Lower Paleolithic period. Therein, writing emerged with a pictographic script, Proto-cuneiform , in the Uruk IV period ( c.  late 4th millennium BC ). The documented record of actual historical events—and

12075-417: The world's first commercial microwave oven post World War II from British radar technology developed before and during the war. Named the "RadaRange", it was first sold in 1947. Raytheon later licensed its patents for a home-use microwave oven that was introduced by Tappan in 1955, but it was still too large and expensive for general home use. Sharp Corporation introduced the first microwave oven with

12190-812: The world's most ancient highly developed, and socially complex states. The region was one of the four riverine civilizations where writing was invented, along with the Nile valley in Ancient Egypt , the Indus Valley civilization in the Indian subcontinent , and the Yellow River in Ancient China . Mesopotamia housed historically important cities such as Uruk , Nippur , Nineveh , Assur and Babylon , as well as major territorial states such as

12305-527: Was also unique. This resulted in an oven that could survive a no-load condition: an empty microwave oven where there is nothing to absorb the microwaves. The new oven was shown at a trade show in Chicago, and helped begin a rapid growth of the market for home microwave ovens. Sales volume of 40,000 units for the U.S. industry in 1970 grew to one million by 1975. Market penetration was even faster in Japan, due to

12420-482: Was an important contribution to astronomy and the philosophy of science and some scholars have thus referred to this new approach as the first scientific revolution. This new approach to astronomy was adopted and further developed in Greek and Hellenistic astronomy. In Seleucid and Parthian times, the astronomical reports were thoroughly scientific. How much earlier their advanced knowledge and methods were developed

12535-500: Was converted to a time-mile used for measuring the travel of the Sun, therefore, representing time. The roots of algebra can be traced to the ancient Babylonia who developed an advanced arithmetical system with which they were able to do calculations in an algorithmic fashion. The Babylonian clay tablet YBC 7289 ( c.  1800 –1600 BC) gives an approximation of √ 2 in four sexagesimal figures, 1 24 51 10 , which

12650-412: Was instrumental in early map-making . The Babylonians also had theorems on how to measure the area of several shapes and solids. They measured the circumference of a circle as three times the diameter and the area as one-twelfth the square of the circumference, which would be correct if π were fixed at 3. The volume of a cylinder was taken as the product of the area of the base and the height; however,

12765-630: Was more generally applied to all the lands between the Euphrates and the Tigris , thereby incorporating not only parts of Syria but also almost all of Iraq and southeastern Turkey . The neighbouring steppes to the west of the Euphrates and the western part of the Zagros Mountains are also often included under the wider term Mesopotamia . A further distinction is usually made between Northern or Upper Mesopotamia and Southern or Lower Mesopotamia . Upper Mesopotamia, also known as

12880-407: Was popcorn, and the second was an egg, which exploded in the face of one of the experimenters. To verify his finding, Spencer created a high-density electromagnetic field by feeding microwave power from a magnetron into a metal box from which it had no way to escape. When food was placed in the box with the microwave energy, the temperature of the food rose rapidly. On 8 October 1945, Raytheon filed

12995-494: Was probably popular, with men sitting on the shoulders of other men rather than on horses. Microwave oven A microwave oven or simply microwave is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to vibrate and produce thermal energy in a process known as dielectric heating . Microwave ovens heat foods quickly and efficiently because excitation

13110-450: Was the first recorded. Mesopotamians believed that the world was a flat disc, surrounded by a huge, holed space, and above that, heaven . They believed that water was everywhere, the top, bottom and sides, and that the universe was born from this enormous sea. Mesopotamian religion was polytheistic . Although the beliefs described above were held in common among Mesopotamians, there were regional variations. The Sumerian word for universe

13225-412: Was the first to offer a microprocessor controlled digital control panel in 1975 with their RR-6 model. The late 1970s saw an explosion of low-cost countertop models from many major manufacturers. Formerly found only in large industrial applications, microwave ovens increasingly became a standard fixture of residential kitchens in developed countries . By 1986, roughly 25% of households in the U.S. owned

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