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89-458: Although partly functional, wind vanes are generally decorative, often featuring the traditional cockerel design with letters indicating the points of the compass . Other common motifs include ships, arrows, and horses. Not all wind vanes have pointers. In a sufficiently strong wind, the head of the arrow or cockerel (or equivalent) will indicate the direction from which the wind is blowing. Wind vanes are also found on small wind turbines to keep

178-414: A predator is approaching from the air or on the ground. To initiate courting, some roosters may dance in a circle around or near a hen (a circle dance), often lowering the wing which is closest to the hen. The dance triggers a response in the hen and when she responds to his call, the rooster may mount the hen and proceed with the mating. Mating typically involves a sequence in which the male approaches

267-434: A beam of light from a laser that is divided into two beams, with one propagated out of the anemometer. Particulates (or deliberately introduced seed material) flowing along with air molecules near where the beam exits reflect, or backscatter, the light back into a detector, where it is measured relative to the original laser beam. When the particles are in great motion, they produce a Doppler shift for measuring wind speed in

356-597: A bird-shaped weather vane situated on a tower roof. The oldest surviving weather vane with the shape of a rooster is the Gallo di Ramperto , made in 820 and now preserved in the Museo di Santa Giulia in Brescia , Lombardy . Pope Leo IV (in office 847 to 855) had a cock placed on the Old St. Peter's Basilica or old Constantinian basilica. Pope Gregory I (in office 590 to 604) regarded

445-511: A coordinated readout. According to the Guinness World Records , the world's largest weather vane is a Tío Pepe sherry advertisement located in Jerez , Spain. The city of Montague, Michigan also claims to have the largest standard-design weather vane, being a ship and arrow which measures 48 feet (15 m) tall, with an arrow 26 feet (7.9 m) long. A challenger for the title of

534-467: A few preferred locations, rather than having a different nest for every bird. Under natural conditions, most birds lay only until a clutch is complete; they then incubate all the eggs. This is called "going broody ". The hen sits on the nest, fluffing up or pecking defensively if disturbed. She rarely leaves the nest until the eggs have hatched. Eggs of chickens from the high-altitude region of Tibet have special physiological adaptations that result in

623-421: A higher hatching rate in low oxygen environments. When eggs are placed in a hypoxic environment, chicken embryos from these populations express much more hemoglobin than embryos from other chicken populations. This hemoglobin has a greater affinity for oxygen, binding oxygen more readily. Fertile chicken eggs hatch at the end of the incubation period, about 21 days; the chick uses its egg tooth to break out of

712-481: A measurement of velocity in 1-, 2-, or 3-dimensional flow. Two-dimensional (wind speed and wind direction) sonic anemometers are used in applications such as weather stations , ship navigation, aviation, weather buoys and wind turbines. Monitoring wind turbines usually requires a refresh rate of wind speed measurements of 3 Hz, easily achieved by sonic anemometers. Three-dimensional sonic anemometers are widely used to measure gas emissions and ecosystem fluxes using

801-646: A sacred rooster, often during a ritual cockfight , used as a form of communication with the gods. In Gabriel García Márquez 's Nobel-Prize-winning 1967 novel One Hundred Years Of Solitude , cockfighting is outlawed in the town of Macondo after the patriarch of the Buendia family murders his cockfighting rival and is haunted by the man's ghost. Chicken jokes have been made at least since The Knickerbocker published one in 1847. Chickens have been featured in art in farmyard scenes such as Adriaen van Utrecht 's 1646 Turkeys and Chickens and Walter Osborne 's 1885 Feeding

890-427: A short distance. Size and coloration vary widely between breeds. Adult chickens of both sexes have a fleshy crest on their heads called a comb or cockscomb, and hanging flaps of skin on either side under their beaks called wattles ; combs and wattles are more prominent in males . Some breeds have a mutation that causes extra feathering under the face, giving the appearance of a beard. Chickens are omnivores . In

979-401: A single domestication event of the red junglefowl in present-day Thailand gave rise to the modern chicken with minor transitions separating the modern breeds. The red junglefowl is well adapted to take advantage of the vast quantities of seed produced during the end of the multi-decade bamboo seeding cycle , to boost its own reproduction. In domesticating the chicken, humans took advantage of

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1068-428: A small purpose-built cavity in order to perform their measurement. Built into the cavity is an array of ultrasonic transducers, which are used to create the separate standing-wave patterns at ultrasonic frequencies. As wind passes through the cavity, a change in the wave's property occurs (phase shift). By measuring the amount of phase shift in the received signals by each transducer, and then by mathematically processing

1157-428: A tag to one cup, causing the cupwheel speed to increase and decrease as the tag moved alternately with and against the wind. Wind direction is calculated from these cyclical changes in speed, while wind speed is determined from the average cupwheel speed. Three-cup anemometers are currently the industry standard for wind resource assessment studies and practice. One of the other forms of mechanical velocity anemometer

1246-512: A total population of 26.5 billion as of 2023 , and an annual production of more than 50 billion birds. A hen bred for laying can produce over 300 eggs per year. There are numerous cultural references to chickens in folklore, religion, and literature. Terms for chickens include: Chicken can mean a chick , as in William Shakespeare 's play Macbeth , where Macduff laments the death of "all my pretty chickens and their dam". The usage

1335-557: A vector for bacterial diseases such as salmonellosis and spirochaetosis . Viral diseases include avian influenza . Chickens are common and widespread domestic animals, with a total population of 23.7 billion as of 2018 . More than 50 billion chickens are reared annually as a source of meat and eggs. In the United States alone, more than 8 billion chickens are slaughtered each year for meat, and more than 300 million chickens are reared for egg production. The vast majority of poultry

1424-410: A vertical shaft. The air flow past the cups in any horizontal direction turned the shaft at a rate roughly proportional to the wind's speed. Therefore, counting the shaft's revolutions over a set time interval produced a value proportional to the average wind speed for a wide range of speeds. This type of instrument is also called a rotational anemometer. With a four-cup anemometer, the wind always has

1513-458: A vertically mounted glass U tube containing a liquid manometer (pressure gauge), with one end bent out in a horizontal direction to face the wind flow and the other vertical end capped. Though the Lind was not the first, it was the most practical and best known anemometer of this type. If the wind blows into the mouth of a tube, it causes an increase of pressure on one side of the manometer. The wind over

1602-611: Is a contest held in a ring called a cockpit between two cocks. Cockfighting is outlawed in many countries as involving cruelty to animals . The activity seems to have been practised in the Indus Valley civilisation from 2500 to 2100 BC. In the process of domestication, chickens were apparently kept initially for cockfighting, and only later used for food. Chickens have long been used as model organisms to study developing embryos. Large numbers of embryos can be provided commercially; fertilized eggs can easily be opened and used to observe

1691-578: Is a device that measures wind speed and direction . It is a common instrument used in weather stations . The earliest known description of an anemometer was by Italian architect and author Leon Battista Alberti (1404–1472) in 1450. The anemometer has changed little since its development in the 15th century. Alberti is said to have invented it around 1450. In the ensuing centuries numerous others, including Robert Hooke (1635–1703), developed their own versions, with some mistakenly credited as its inventor. In 1846, Thomas Romney Robinson (1792–1882) improved

1780-461: Is also required in monitoring and controlling the operation of wind turbines, which in cold environments are prone to in-cloud icing. Icing alters the aerodynamics of an anemometer and may entirely block it from operating. Therefore, anemometers used in these applications must be internally heated. Both cup anemometers and sonic anemometers are presently available with heated versions. In order for wind speeds to be comparable from location to location,

1869-547: Is dependent upon the temperature of the metal ( tungsten is a popular choice for hot-wires), a relationship can be obtained between the resistance of the wire and the speed of the air. In most cases, they cannot be used to measure the direction of the airflow, unless coupled with a wind vane. Several ways of implementing this exist, and hot-wire devices can be further classified as CCA ( constant current anemometer), CVA ( constant voltage anemometer) and CTA (constant-temperature anemometer). The voltage output from these anemometers

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1958-592: Is inhumane towards sentient animals . Advocates of intensive farming say that their efficient systems save land and food resources owing to increased productivity, and that the animals are looked after in a controlled environment. Chickens farmed for meat are called broilers . Broiler breeds typically take less than six weeks to reach slaughter size, some weeks longer for free range and organic broilers. Chickens farmed primarily for eggs are called layer hens. The UK alone consumes more than 34 million eggs per day. Hens of some breeds can produce over 300 eggs per year;

2047-409: Is inversely proportionate to the speed of sound in air plus the wind velocity in the same direction: t = L ( c + v ) {\displaystyle t={\frac {L}{(c+v)}}} where t {\displaystyle t} is the time of flight, L {\displaystyle L} is the distance between transducers, c {\displaystyle c}

2136-518: Is measured against the air pressure in an ordinary room in which the doors and windows are carefully closed and a newspaper is then burnt up the chimney, an effect may be produced equal to a wind of 10 mi/h (16 km/h); and the opening of a window in rough weather, or the opening of a door, may entirely alter the registration. While the Dines anemometer had an error of only 1% at 10 mph (16 km/h), it did not respond very well to low winds due to

2225-407: Is measurement accuracy when compared to a calibrated mechanical sensor. For many end uses, this weakness is compensated for by the sensor's longevity and the fact that it does not require recalibration once installed. The first designs of anemometers that measure the pressure were divided into plate and tube classes. These are the first modern anemometers. They consist of a flat plate suspended from

2314-403: Is not in the shape of a rooster, but of a key ; while St Lawrence Jewry 's weather vane has the form of a gridiron (symbolising Saint Lawrence ). Early weather-vanes had very ornamental pointers, but modern weather-vanes usually feature simple arrows that dispense with the directionals because the instrument is connected to a remote reading station. An early example of this was installed in

2403-507: Is preserved in placenames such as the Hen and Chicken Islands . In older sources, and still often in trade and scientific contexts, chickens as a species are described as common fowl or domestic fowl . Chickens are relatively large birds , active by day . The body is round, the legs are unfeathered in most breeds, and the wings are short. Wild junglefowl can fly ; chickens and their flight muscles are too heavy to allow them to fly more than

2492-468: Is raised in factory farms . According to the Worldwatch Institute , 74% of the world's poultry meat and 68% of eggs are produced this way. An alternative to intensive poultry farming is free-range farming. Friction between these two main methods has led to long-term issues of ethical consumerism . Opponents of intensive farming argue that it harms the environment, creates human health risks and

2581-411: Is reached, at which time the pulse is sent again. Hot-wire anemometers, while extremely delicate, have extremely high frequency-response and fine spatial resolution compared to other measurement methods, and as such are almost universally employed for the detailed study of turbulent flows, or any flow in which rapid velocity fluctuations are of interest. An industrial version of the fine-wire anemometer

2670-513: Is supplemented by mentions in historical texts from the last few centuries BC, and by depictions in prehistoric artworks, such as across Central Asia. Chickens were widespread throughout southern Central Asia by the 4th century BC. Middle Eastern chicken remains go back to a little earlier than 2000 BC in Syria . Phoenicians spread chickens along the Mediterranean coasts as far as Iberia. During

2759-465: Is the thermal flow meter , which follows the same concept, but uses two pins or strings to monitor the variation in temperature. The strings contain fine wires, but encasing the wires makes them much more durable and capable of accurately measuring air, gas, and emissions flow in pipes, ducts, and stacks. Industrial applications often contain dirt that will damage the classic hot-wire anemometer. In laser Doppler velocimetry , laser Doppler anemometers use

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2848-452: Is the vane anemometer . It may be described as a windmill or a propeller anemometer. Unlike the Robinson anemometer, whose axis of rotation is vertical, the vane anemometer must have its axis parallel to the direction of the wind and is therefore horizontal. Furthermore, since the wind varies in direction and the axis has to follow its changes, a wind vane or some other contrivance to fulfill

2937-452: Is the distortion of the air flow by the structure supporting the transducers, which requires a correction based upon wind tunnel measurements to minimize the effect. Rain drops or ice on the transducers can also cause inaccuracies. Since the speed of sound varies with temperature, and is virtually stable with pressure change, ultrasonic anemometers are also used as thermometers . Measurements from pairs of transducers can be combined to yield

3026-463: Is the forward time of flight and t 2 {\displaystyle t_{2}} the reverse. Because ultrasonic anenometers have no moving parts, they need little maintenance and can be used in harsh environments. They operate over a wide range of wind speeds. They can measure rapid changes in wind speed and direction, taking many measurements each second, and so are useful in measuring turbulent air flow patterns. Their main disadvantage

3115-689: Is the speed of sound in air and v {\displaystyle v} is the wind velocity. In other words, the faster the wind is blowing, the faster the sound pulse travels. To correct for the speed of sound in air (which varies according to temperature, pressure and humidity) sound pulses are sent in both directions and the wind velocity is calculated using the forward and reverse times of flight: v = 1 2 L ( 1 t 1 − 1 t 2 ) {\displaystyle v={\frac {1}{2}}L({\frac {1}{t_{1}}}-{\frac {1}{t_{2}}})} where t 1 {\displaystyle t_{1}}

3204-417: Is thus the result of some sort of circuit within the device trying to maintain the specific variable (current, voltage or temperature) constant, following Ohm's law . Additionally, PWM ( pulse-width modulation ) anemometers are also used, wherein the velocity is inferred by the time length of a repeating pulse of current that brings the wire up to a specified resistance and then stops until a threshold "floor"

3293-540: The Arauco Peninsula in south-central Chile were radiocarbon dated as pre-Columbian, and DNA analysis suggested they were related to prehistoric populations in Polynesia. However, further study of the same bones cast doubt on the findings. Chicken remains have been difficult to date, given the small and fragile bird bones; this may account for discrepancies in dates given by different sources. Archaeological evidence

3382-605: The Gonadotropin-Releasing Hormone-I neurons in the hypothalamus . Reproductive hormones including estrogen , progesterone , and gonadotropins ( luteinizing hormone and follicle-stimulating hormone ) initiate and maintain sexual maturation changes. Reproduction declines with age, thought to be due to a decline in GnRH-I-N. Hens often try to lay in nests that already contain eggs and sometimes move eggs from neighbouring nests into their own. A flock thus uses only

3471-609: The Hellenistic period (4th–2nd centuries BC), in the southern Levant , chickens began to be widely domesticated for food. The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC. Breeding increased under the Roman Empire and reduced in the Middle Ages . Genetic sequencing of chicken bones from archaeological sites in Europe revealed that in

3560-751: The High Middle Ages chickens became less aggressive and began to lay eggs earlier in the breeding season. Chickens reached Egypt via the Middle East for purposes of cockfighting about 1400 BC and became widely bred in Egypt around 300 BC. Three possible routes of introduction into Africa around the early first millennium AD could have been through the Egyptian Nile Valley, the East Africa Roman-Greek or Indian trade, or from Carthage and

3649-479: The Three Kingdoms period of China (220–280 AD) refer to the weather vane as "five ounces" ( wu liang , 五兩 ), named after the weight of its materials. By the third century, Chinese weather vanes were shaped like birds and took the name of "wind-indicating bird" ( xiang feng wu , 相風烏 ). The Sanfu huangtu ( 三輔黃圖 ), a third-century book written by Miao Changyan about the palaces at Chang'an , describes

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3738-412: The eddy covariance method when used with fast-response infrared gas analyzers or laser -based analyzers. Acoustic resonance anemometers are a more recent variant of sonic anemometer. The technology was invented by Savvas Kapartis and patented in 1999. Whereas conventional sonic anemometers rely on time of flight measurement, acoustic resonance sensors use resonating acoustic (ultrasonic) waves within

3827-570: The 1070s depicts a man installing a cock on Westminster Abbey . One alternative theory about the origin of weathercocks on church steeples sees them as emblems of the vigilance of the clergy calling the people to prayer. Another theory says that the cock was not a Christian symbol but an emblem of the sun derived from the Goths. A few churches used weather vanes in the shape of the emblems of their patron saints. The City of London has two surviving examples. The weather vane of St Peter upon Cornhill

3916-609: The Americas before Western contact is debated by researchers, but blue-egged chickens, found only in the Americas and Asia, suggest an Asian origin for early American chickens. A lack of data from Thailand, Russia, the Indian subcontinent, Southeast Asia and Sub-Saharan Africa makes it difficult to lay out a clear map of the spread of chickens in these areas; better description and genetic analysis of local breeds threatened by extinction may also help with research into this area. Chicken bones from

4005-524: The Berbers, across the Sahara . The earliest known remains are from Mali , Nubia , East Coast, and South Africa and date back to the middle of the first millennium AD. Chickens are susceptible both to parasites such as mites , and to diseases caused by pathogens such as bacteria and viruses . The parasite Dermanyssus gallinae feeds on blood, causing irritation and reducing egg production, and acts as

4094-615: The Chickens . The nursery rhyme " Cock a doodle doo ", its chorus line imitating the cockerel's call, was published in Mother Goose's Melody in 1765. The 2000 animated adventure comedy film Chicken Run , directed by Peter Lord and Nick Park , featured anthropomorphic chickens with many chicken jokes. Aerovane In meteorology , an anemometer (from Ancient Greek άνεμος ( ánemos )  'wind' and μέτρον ( métron )  'measure')

4183-517: The Royal Navy's Admiralty building in London – the vane on the roof was mechanically linked to a large dial in the boardroom so senior officers were always aware of the wind direction when they met. Modern aerovanes combine the directional vane with an anemometer (a device for measuring the speed of the wind). Co-locating both instruments allows them to use the same axis (a vertical rod) and provides

4272-479: The UK and Europe, laying hens are then slaughtered and used in processed foods, or sold as 'soup hens'. In some other countries, flocks are sometimes force moulted rather than being slaughtered to re-invigorate egg-laying. This involves complete withdrawal of food (and sometimes water) for 7–14 days or sufficiently long to cause a body weight loss of 25 to 35%, or up to 28 days under experimental conditions. This stimulates

4361-486: The United States in 1935, led to a cupwheel design with a nearly linear response and an error of less than 3% up to 60 mph (97 km/h). Patterson found that each cup produced maximum torque when it was at 45° to the wind flow. The three-cup anemometer also had a more constant torque and responded more quickly to gusts than the four-cup anemometer. The three-cup anemometer was further modified by Australian Dr. Derek Weston in 1991 to also measure wind direction. He added

4450-513: The Winds in the agora in Hellenistic Athens once bore on its roof a weather vane in the form of a bronze Triton holding a rod in his outstretched hand, rotating as the wind changed direction. Below this a frieze depicted the eight Greek wind deities . The eight-metre-high structure also featured sundials , and a water clock inside. It dated from around 50 BC. Military documents from

4539-473: The actual air density differs from the calibration value, due to differing temperature, elevation or barometric pressure, a correction is required to obtain the actual wind speed. Approximately 1.5% (1.6% above 6,000 feet) should be added to the velocity recorded by a tube anemometer for each 1000 ft (5% for each kilometer) above sea-level. At airports, it is essential to have accurate wind data under all conditions, including freezing precipitation. Anemometry

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4628-425: The airspeed of aircraft. The pitot port measures the dynamic pressure of the open mouth of a tube with pointed head facing the wind, and the static port measures the static pressure from small holes along the side on that tube. The pitot tube is connected to a tail so that it always makes the tube's head face the wind. Additionally, the tube is heated to prevent rime ice formation on the tube. There are two lines from

4717-480: The angle between the string-ball apparatus and the vertical gives an estimate of the wind speed. This type of anemometer is mostly used for middle-school level instruction, which most students make on their own, but a similar device was also flown on the Phoenix Mars Lander . In the tube anemometer the dynamic pressure is actually being measured, although the scale is usually graduated as a velocity scale. If

4806-425: The chicken genome is similarly sized compared to other birds, but smaller than nearly all mammals: the human genome is 3.2 Gb . The final gene set contained 26,640 genes (including noncoding genes and pseudogenes ), with a total of 19,119 protein-coding genes, a similar number to the human genome. In 2006, scientists researching the ancestry of birds switched on a chicken recessive gene , talpid2 , and found that

4895-468: The cock as "the most suitable emblem of Christianity", being the emblem of Saint Peter (a reference to Luke 22:34 in which Jesus predicts that Peter will deny him three times before the rooster crows). As a result of this, rooster representations gradually came into use as a weather vanes on church steeples, and in the ninth century Pope Nicholas I (in office 858 to 867) ordered the figure to be placed on every church steeple. The Bayeux Tapestry of

4984-607: The cups moved one-third of the speed of the wind, unaffected by cup size or arm length. This was apparently confirmed by some early independent experiments, but it was incorrect. Instead, the ratio of the speed of the wind and that of the cups, the anemometer factor , depends on the dimensions of the cups and arms, and can have a value between two and a little over three. Once the error was discovered, all previous experiments involving anemometers had to be repeated. The three-cup anemometer developed by Canadian John Patterson in 1926, and subsequent cup improvements by Brevoort & Joiner of

5073-643: The data, the sensor is able to provide an accurate horizontal measurement of wind speed and direction. Because acoustic resonance technology enables measurement within a small cavity, the sensors tend to be typically smaller in size than other ultrasonic sensors. The small size of acoustic resonance anemometers makes them physically strong and easy to heat, and therefore resistant to icing. This combination of features means that they achieve high levels of data availability and are well suited to wind turbine control and to other uses that require small robust sensors such as battlefield meteorology. One issue with this sensor type

5162-528: The design by using four hemispherical cups and mechanical wheels. In 1926, Canadian meteorologist John Patterson (1872–1956) developed a three-cup anemometer, which was improved by Brevoort and Joiner in 1935. In 1991, Derek Weston added the ability to measure wind direction. In 1994, Andreas Pflitsch developed the sonic anemometer. A simple type of anemometer was invented in 1845 by Rev. Dr. John Thomas Romney Robinson of Armagh Observatory . It consisted of four hemispherical cups on horizontal arms mounted on

5251-446: The developing embryo. Equally important, embryologists can carry out experiments on such embryos, close the egg again and study the effects later in development. For instance, many important discoveries in limb development have been made using chicken embryos, such as the discovery of the apical ectodermal ridge and the zone of polarizing activity . The chicken was the first bird species to have its genome sequenced. At 1.21 Gb ,

5340-399: The direction of the air motion is always the same, as in ventilating shafts of mines and buildings, wind vanes known as air meters are employed, and give satisfactory results. Hot wire anemometers use a fine wire (on the order of several micrometres) electrically heated to some temperature above the ambient. Air flowing past the wire cools the wire. As the electrical resistance of most metals

5429-406: The embryo jaws initiated formation of teeth, like those found in ancient bird fossils. Chickens are featured widely in folklore , religion , literature , and popular culture. The chicken is a sacred animal in many cultures and deeply embedded in belief systems and religious practices. Roosters are sometimes used for divination , a practice called alectryomancy. This involves the sacrifice of

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5518-425: The entire range of the prehistoric Austronesian maritime migrations to Island Southeast Asia , Micronesia , Island Melanesia , Polynesia , and Madagascar , starting from at least 3000 BC from Taiwan . These chickens might have been introduced during pre-Columbian times to South America via Polynesian seafarers, but evidence for this is still putative. The possibility that domestic chickens were in

5607-417: The female and performs a waltzing display. If the female is unreceptive, she runs off; otherwise, she crouches, and the male mounts, treading with both feet on her back. After copulation the male does a tail-bending display. Sperm transfer occurs by cloacal contact between the male and female, in an action called the 'cloacal kiss'. As with all birds, reproduction is controlled by a neuroendocrine system,

5696-520: The first egg is laid and egg number. Water or ground-dwelling fowl similar to modern partridges , in the Galliformes , the order of bird that chickens belong to, survived the Cretaceous–Paleogene extinction event that killed all tree-dwelling birds and their dinosaur relatives. Chickens are descended primarily from the red junglefowl ( Gallus gallus ) and are scientifically classified as

5785-949: The hen to lose her feathers but also re-invigorates egg-production. Some flocks may be force-moulted several times. In 2003, more than 75% of all flocks were moulted in the US. Keeping chickens as pets became increasingly popular in the 2000s among urban and suburban residents. Many people obtain chickens for their egg production but often name them and treat them as any other pet like cats or dogs. Chickens provide companionship and have individual personalities. While many do not cuddle much, they will eat from one's hand, jump onto one's lap, respond to and follow their handlers, as well as show affection. Chickens are social, inquisitive, intelligent birds, and many people find their behaviour entertaining. Certain breeds, such as silkies and many bantam varieties, are generally docile and are often recommended as good pets around children with disabilities. A cockfight

5874-418: The highest authenticated rate of egg laying is 371 eggs in 364 days. After 12 months of laying, the commercial hen's egg-laying ability declines to the point where the flock is commercially unviable. Hens, particularly from battery cage systems, are sometimes infirm or have lost a significant amount of their feathers, and their life expectancy has been reduced from around seven years to less than two years. In

5963-458: The hollow of one cup presented to it, and is blowing on the back of the opposing cup. Since a hollow hemisphere has a drag coefficient of .38 on the spherical side and 1.42 on the hollow side, more force is generated on the cup that presenting its hollow side to the wind. Because of this asymmetrical force, torque is generated on the anemometer's axis, causing it to spin. Theoretically, the anemometer's speed of rotation should be proportional to

6052-407: The laser light, which is used to calculate the speed of the particles, and therefore the air around the anemometer. Ultrasonic anemometers, first developed in the 1950s, use ultrasonic sound waves to measure wind velocity. They measure wind speed based on the time of flight of sonic pulses between pairs of transducers . The time that a sonic pulse takes to travel from one transducer to its pair

6141-481: The legislature. [REDACTED] Media related to Weather vanes at Wikimedia Commons Chicken Gallus domesticus L. The chicken ( Gallus domesticus ) is a large and round short-winged bird , domesticated from the red junglefowl of Southeast Asia around 8,000 years ago. Most chickens are raised for food, providing meat and eggs ; others are kept as pets or for cockfighting . Chickens are common and widespread domestic animals, with

6230-524: The most popular commercial breed shows that the White Leghorn breed possesses a mosaic of divergent ancestries inherited from subspecies of red junglefowl. A word for the domestic chicken ( *manuk ) is part of the reconstructed Proto-Austronesian language , indicating they were domesticated by the Austronesian peoples since ancient times. Chickens, together with dogs and pigs, were carried throughout

6319-487: The open end of a vertical tube causes little change in pressure on the other side of the manometer. The resulting elevation difference in the two legs of the U tube is an indication of the wind speed. However, an accurate measurement requires that the wind speed be directly into the open end of the tube; small departures from the true direction of the wind causes large variations in the reading. The successful metal pressure tube anemometer of William Henry Dines in 1892 utilized

6408-423: The poor response of the flat plate vane required to turn the head into the wind. In 1918 an aerodynamic vane with eight times the torque of the flat plate overcame this problem. Modern tube anemometers use the same principle as in the Dines anemometer, but using a different design. The implementation uses a pitot-static tube , which is a pitot tube with two ports, pitot and static, that is normally used in measuring

6497-602: The red junglefowl's ability to reproduce prolifically when exposed to a surge in its food supply. Exactly when and where the chicken was domesticated remains controversial. Genomic studies estimate that the chicken was domesticated 8,000 years ago in Southeast Asia and spread to China and India 2,000 to 3,000 years later. Archaeological evidence supports domestic chickens in Southeast Asia well before 6000 BC, China by 6000 BC and India by 2000 BC. A landmark 2020 Nature study that fully sequenced 863 chickens across

6586-447: The registering part can be placed in any convenient position. Two connecting tubes are required. It might appear at first sight as though one connection would serve, but the differences in pressure on which these instruments depend are so minute, that the pressure of the air in the room where the recording part is placed has to be considered. Thus, if the instrument depends on the pressure or suction effect alone, and this pressure or suction

6675-416: The same pressure difference between the open mouth of a straight tube facing the wind and a ring of small holes in a vertical tube which is closed at the upper end. Both are mounted at the same height. The pressure differences on which the action depends are very small, and special means are required to register them. The recorder consists of a float in a sealed chamber partially filled with water. The pipe from

6764-416: The same purpose must be employed. A vane anemometer thus combines a propeller and a tail on the same axis to obtain accurate and precise wind speed and direction measurements from the same instrument. The speed of the fan is measured by a revolution counter and converted to a windspeed by an electronic chip. Hence, volumetric flow rate may be calculated if the cross-sectional area is known. In cases where

6853-462: The same species. Domesticated chickens freely interbreed with populations of red junglefowl. The domestic chicken has subsequently hybridised with grey junglefowl , Sri Lankan junglefowl and green junglefowl ; a gene for yellow skin, for instance, was incorporated into domestic birds from the grey junglefowl ( G. sonneratii ). It is estimated that chickens share between 71 and 79% of their genome with red junglefowl. According to one early study,

6942-703: The shell. Hens remain on the nest for about two days after the first chick hatches; during this time the newly hatched chicks feed by absorbing the internal yolk sac . The hen guards her chicks and broods them to keep them warm. She leads them to food and water and calls them towards food. The chicks imprint on the hen and subsequently follow her continually. She continues to care for them until they are several weeks old. Inbreeding of White Leghorn chickens tends to cause inbreeding depression expressed as reduced egg number and delayed sexual maturity. Strongly inbred Langshan chickens display obvious inbreeding depression in reproduction, particularly for traits such as age when

7031-409: The spring determines the actual force which the wind is exerting on the plate, and this is either read off on a suitable gauge, or on a recorder. Instruments of this kind do not respond to light winds, are inaccurate for high wind readings, and are slow at responding to variable winds. Plate anemometers have been used to trigger high wind alarms on bridges. James Lind 's anemometer of 1775 consisted of

7120-423: The straight tube is connected to the top of the sealed chamber and the pipe from the small tubes is directed into the bottom inside the float. Since the pressure difference determines the vertical position of the float this is a measure of the wind speed. The great advantage of the tube anemometer lies in the fact that the exposed part can be mounted on a high pole, and requires no oiling or attention for years; and

7209-459: The top so that the wind deflects the plate. In 1450, the Italian art architect Leon Battista Alberti invented the first such mechanical anemometer; in 1663 it was re-invented by Robert Hooke. Later versions of this form consisted of a flat plate, either square or circular, which is kept normal to the wind by a wind vane. The pressure of the wind on its face is balanced by a spring. The compression of

7298-437: The tube down to the devices to measure the difference in pressure of the two lines. The measurement devices can be manometers , pressure transducers , or analog chart recorders . A common anemometer for basic use is constructed from a ping-pong ball attached to a string. When the wind blows horizontally, it presses on and moves the ball; because ping-pong balls are very lightweight, they move easily in light winds. Measuring

7387-530: The wild, they scratch at the soil to search for seeds, insects, and animals as large as lizards , small snakes, and young mice . A chicken may live for 5–10 years, depending on the breed . The world's oldest known chicken lived for 16 years. Chickens are gregarious , living in flocks , and incubate eggs and raise young communally. Individual chickens dominate others, establishing a pecking order ; dominant individuals take priority for access to food and nest sites. The concept of dominance, involving pecking,

7476-414: The wind speed because the force produced on an object is proportional to the speed of the gas or fluid flowing past it. However, in practice, other factors influence the rotational speed, including turbulence produced by the apparatus, increasing drag in opposition to the torque produced by the cups and support arms, and friction on the mount point. When Robinson first designed his anemometer, he asserted that

7565-544: The wind turbine pointing into the wind. The oldest known textual references to weather vanes date from 1800-1600 BCE Babylon, where a fable called The Fable of the Willow describes people looking at a weather vane "for the direction of the wind." In China, the Huainanzi , dating from around 139 BC, mentions a thread or streamer that another commentator interprets as "wind-observing fan" ( hou feng shin , 侯風扇 ). The Tower of

7654-404: The world suggests that all domestic chickens originate from a single domestication event of red junglefowl whose present-day distribution is predominantly in southwestern China, northern Thailand and Myanmar. These domesticated chickens spread across Southeast and South Asia where they interbred with local wild species of junglefowl, forming genetically and geographically distinct groups. Analysis of

7743-546: The world's largest weather vane is located in Whitehorse, Yukon . The weather vane is a retired Douglas DC-3 CF-CPY atop a swiveling support. Located at the Yukon Transportation Museum beside Whitehorse International Airport , the weather vane is used by pilots to determine wind direction, used as a landmark by tourists and enjoyed by locals. The weather vane only requires a 5 knot wind to rotate. A challenger for

7832-565: The world's tallest weather vane is located in Westlock , Alberta . The classic weather vane that reaches to 50 feet (15 m) is topped by a 1942 Case Model D Tractor. This landmark is located at the Canadian Tractor Museum. The term "weather vane" is also a slang word for a politician who has frequent changes of opinion. The National Assembly of Quebec has banned the use of this slang term as an insult after its use by members of

7921-553: Was described in female chickens by Thorleif Schjelderup-Ebbe in 1921 as the "pecking order". Male chickens tend to leap and use their claws in conflicts. Chickens are capable of mobbing and killing a weak or inexperienced predator, such as a young fox. A male's crowing is a loud and sometimes shrill call, serving as a territorial signal to other males, and in response to sudden disturbances within their surroundings. Hens cluck loudly after laying an egg and to call their chicks. Chickens give different warning calls to indicate that

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