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  • water hen (bird)

    Moorhen, bird species also called common gallinule. See

  • water hen (bird, Porphyrula martinica)

    gallinule: The purple gallinule of America (Porphyrula martinica), sometimes called water hen or sultana, is about 30 cm long and is bright olive green and purplish blue with a light blue shield, red and yellow bill, and yellow legs and feet. It is found from South Carolina…

  • water hog (rodent)

    Capybara, (Hydrochoerus hydrochaeris), the largest living rodent, a semiaquatic mammal of Central and South America. The capybara is the sole member of the family Hydrochoeridae. It resembles the cavy and guinea pig of the family Caviidae. South American capybaras may be 1.25 metres (4 feet) long

  • water horn fern (plant)

    water fern: cornuta); floating antlerfern, or water horn fern (C. pteridoides); triangle water fern (C. richardii); and water sprite (C. thalictroides). The plants are widespread in tropical and warm temperate regions around the world, and several are cultivated as aquarium plants. Although water ferns sometimes root in mud,…

  • water horse (mammal species)

    Hippopotamus, (Hippopotamus amphibius), amphibious African ungulate mammal. Often considered to be the second largest land animal (after the elephant), the hippopotamus is comparable in size and weight to the white rhinoceros (Ceratotherium simum) and the Indian rhinoceros (Rhinoceros unicornis).

  • water hyacinth (plant)

    Water hyacinth, any aquatic plant of the genus Eichhornia of the pickerelweed family (Pontederiaceae), consisting of about five species, native primarily to tropical America. Some species float in shallow water; others are rooted in muddy stream banks and lakeshores. All have slender rootstocks,

  • water ice (solid water)

    Ice, solid substance produced by the freezing of water vapour or liquid water. At temperatures below 0 °C (32 °F), water vapour develops into frost at ground level and snowflakes (each of which consists of a single ice crystal) in clouds. Below the same temperature, liquid water forms a solid, as,

  • water ice (astronomy)

    Phoenix: …discoveries was the existence of water ice beneath the surface of Mars. Phoenix’s robotic arm dug a trench that uncovered a white material that sublimed directly into the atmosphere and therefore was water ice. Minerals, such as calcium carbonate, that form in the presence of water were found. The soil…

  • water ice (food)

    sherbet: Water ice, called in French sorbet and in Italian granita, is similar to sherbet but contains no dairy ingredients.

  • water intoxication

    Overhydration, condition characterized by an excessive volume of water in the body. Overhydration occurs when the body’s ability to dispose of fluid is overcome by a large fluid intake. It also can occur when the mechanisms for the disposal of excess fluid are defective, as is the case when more

  • water kamudi (reptile)

    anaconda: The green anaconda (Eunectes murinus), also called the giant anaconda, sucuri, or water kamudi, is an olive-coloured snake with alternating oval-shaped black spots. The yellow, or southern, anaconda (E. notaeus) is much smaller and has pairs of overlapping spots.

  • water lettuce (plant)

    Africa: Sudd: …other water plants—including the floating Nile cabbage (Pistia stratiotes)—form masses of waterlogged plant material that are largely unproductive and are a nuisance to fishing and navigation. Pistia has become an unwelcome invader of Lake Kariba, the body of water formed by the impounding (1959) of the Zambezi River in the…

  • water level (instrument)

    surveying: History: The water level consisted of either a trough or a tube turned upward at the ends and filled with water. At each end there was a sight made of crossed horizontal and vertical slits. When these were lined up just above the water level, the sights…

  • Water Lilies (work by Monet)

    Claude Monet: Last years: …he began to construct a water-lily garden. Soon weeping willows, iris, and bamboo grew around a free-form pool, clusters of lily pads and blossoms floated on the quiet water, and a Japanese bridge closed the composition at one end. By 1900 this unique product of Monet’s imagination (for his Impressionism…

  • water lily (plant family)

    Water lily, (family Nymphaeaceae), any of 58 species in 6 genera of freshwater plants native to the temperate and tropical parts of the world. Most species of water lilies have rounded, variously notched, waxy-coated leaves on long stalks that contain many air spaces and float in quiet freshwater

  • water lily order (plant order)

    Nymphaeales, the water lily order of flowering plants, a basal branch of angiosperms, or flowering plants, containing 3 families, 9 genera, and 74 species. In older botanical classification systems, the order was included in the dicotyledon class (Magnoliopsida, characterized by two seed leaves).

  • water lobelia (plant)

    Lobelia: Lobelia dortmanna (water lobelia) occurs throughout the north temperate zone. L. urens (acrid lobelia) is found locally in damp pastures in England and western Europe.

  • water main (civil engineering)

    water supply system: Pipelines: …distribution network consists of arterial water mains or primary feeders, which convey water from the treatment plant to areas of major water use in the community, and smaller-diameter pipelines called secondary feeders, which tie in to the mains. Usually not less than 150 mm (6 inches) in diameter, these pipelines…

  • Water Margin (Chinese novel)

    Water Margin, ancient Chinese vernacular novel known from several widely varying manuscripts under the name Shuihuzhuan. Its variations are so extreme as to make the work the most textually complex in Chinese literature; the text cannot be dated with accuracy, and its authors cannot be identified.

  • water mass (oceanography)

    Water mass, body of ocean water with a distinctive narrow range of temperature and salinity and a particular density resulting from these two parameters. Water masses are formed as the result of climatic effects in specific regions. Antarctic bottom water is an important water mass that forms on

  • water meadow (agriculture)
  • water measurer (insect)

    Marsh treader, any insect of the family Hydrometridae (order Heteroptera), so named because of its slow, deliberate manner of moving as it walks along the surface of a pond or crawls among shore vegetation. Marsh treaders, worldwide in distribution, are usually found among the cattails in marshy

  • water milfoil (plant)

    Water milfoil, any member of the genus Myriophyllum (family Haloragaceae), about 45 widely distributed species of submerged freshwater plants with whorls of feathery leaves and emergent, wind-pollinated flowers. Some species are cultivated in pools and aquariums, especially the parrot’s feather,

  • water milfoil family (plant family)

    Saxifragales: Major families: Haloragaceae, or the water milfoil family, comprises 8 genera and 145 species of land, marsh, and water herbs with small leaves and small flower clusters. The flowers are unisexual, generally wind-pollinated, with a three- to four-chambered ovary and a similar number of styles (pollen-receptive parts…

  • water mill (engineering)

    Waterwheel, mechanical device for tapping the energy of running or falling water by means of a set of paddles mounted around a wheel. The force of the moving water is exerted against the paddles, and the consequent rotation of the wheel is transmitted to machinery via the shaft of the wheel. The

  • water mint (plant)

    mint: Water mint (M. aquatica) commonly grows in ditches and has rounded flower spikes and stalked hairy leaves. Wild mint (M. arvensis), native in North America and Eurasia, reaches about 1 metre (about 3.3 feet) high. Pennyroyal, M. pulegium, has small oval obtuse leaves and flowers…

  • water moccasin (snake)

    moccasin: …the viper family (Viperidae): the water moccasin (Agkistrodon piscivorus) or the Mexican moccasin (A. bilineatus). Both are pit vipers (subfamily Crotalinae), so named because of the characteristic sensory pit between each eye and nostril.

  • water mold (chromist)

    Water mold, (order Saprolegniales), order of about 150 species of filamentous funguslike organisms (phylum Oomycota, kingdom Chromista). Many water molds live in fresh or brackish water or wet soils. Most species are saprotrophic (i.e., they live on dead or decaying organic matter), although some

  • water moss (plant)

    Water moss, (Fontinalis), genus of mosses belonging to the subclass Bryidae, often found in flowing freshwater streams and ponds in temperate regions. Of the 20 species of water moss, 18 are native to North America. A brook moss may have shoots 30 to 100 (rarely up to 200) cm (12 to 40 inches) long

  • water mould (chromist)

    Water mold, (order Saprolegniales), order of about 150 species of filamentous funguslike organisms (phylum Oomycota, kingdom Chromista). Many water molds live in fresh or brackish water or wet soils. Most species are saprotrophic (i.e., they live on dead or decaying organic matter), although some

  • Water Music (suite by Handel)

    Water Music, suite of short pieces for small orchestra by German-born English composer George Frideric Handel, known particularly for its highly spirited movements in dance form. Most of the pieces were originally intended for outdoor performance, and the work premiered on a barge on the River

  • water net (green algae)

    Water net, (genus Hydrodictyon), genus of filamentous green algae (family Hydrodictyaceae) sometimes found on the surface of quiet freshwater bodies. Because of its reproductive efficiency, Hydrodictyon proliferates rapidly and can be a problem in ponds, recreational waters, and irrigation canals.

  • water oak (plant)

    willow oak: Water oak (Q. nigra), laurel oak (Q. laurifolia), shingle oak (Q. imbricaria), and live oak (see live oak) are other willow oaks planted as ornamentals in the southern U.S.

  • water oats (plant)

    Wild rice, (genus Zizania), genus of four species of coarse grasses of the family Poaceae, the grain of which is sometimes grown as a delicacy. Despite their name, the plants are not related to true rice (Oryza sativa). Wild rice grows naturally in shallow freshwater marshes and along the shores of

  • water of imbibition (food processing)

    sugar: Juice extraction: …countercurrent of water known as water of maceration or imbibition. Streams of juice extracted from the cane, mixed with maceration water from all mills, are combined into a mixed juice called dilute juice. Juice from the last mill in the series (which does not receive a current of maceration water)…

  • Water of Leith (stream, Edinburgh, Scotland, United Kingdom)

    Edinburgh: City site: …Edinburgh’s only substantial stream, the Water of Leith. The stream’s brief course from the Pentlands to the sea provided power for the mills of a series of villages—Dalry, Dean, Stockbridge, Silvermills, and Canonmills—that experienced significant growth from the early 17th century onward. These villages, which sprang up largely as industrial…

  • water of maceration (food processing)

    sugar: Juice extraction: …countercurrent of water known as water of maceration or imbibition. Streams of juice extracted from the cane, mixed with maceration water from all mills, are combined into a mixed juice called dilute juice. Juice from the last mill in the series (which does not receive a current of maceration water)…

  • Water on the Brain (work by Mackenzie)

    Compton Mackenzie: … (1913–14); a satiric sting in Water on the Brain (1933), attacking the British secret service, which had prosecuted him under the Official Secrets Act for his autobiographical Greek Memories (1932); and a love of pure fun in The Monarch of the Glen (1941) and Whisky Galore (1947). Other novels included…

  • water on the brain (pathology)

    Hydrocephalus, accumulation of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain, causing progressive enlargement of the head. Normally, CSF continuously circulates through the brain and the spinal cord and is continuously drained into the circulatory system. In hydrocephalus

  • water opossum (marsupial)

    Water opossum, (Chironectes minimus), a semiaquatic, web-footed marsupial (family Didelphidae, subfamily Didelphinae) found along tropical rivers, streams, and lakes from Mexico to Argentina. Adults average 70 cm (28 inches) in total length and weigh up to 790 grams (1.7 pounds). A pouch is present

  • water organ (musical instrument)

    Hydraulis, earliest known mechanical pipe organ. It was invented in the 3rd century bc by Ctesibius of Alexandria, culminating prior attempts to apply a mechanical wind supply to a large set of panpipes. Its pipes stood on top of a wind chest that was connected to a conical wind reservoir. The

  • water ouzel (bird)

    Dipper, (genus Cinclus), any of five species of songbirds of the Cinclidae family (order Passeriformes) noted for insect hunting by walking underwater in rushing streams and named for their frequent body bobbing. Among the best-known species are the Eurasian, or white-throated, dipper (Cinclus

  • water parsnip (plant)

    Water parsnip, any of several aromatic herbs of the genus Sium, especially S. latifolium, belonging to the parsley family (Apiaceae), distributed throughout the Northern Hemisphere and Africa. They grow in moist areas, and some species are even partially submerged. All are perennial herbs with

  • water pipe (smoking pipe)

    smoking: Tobacco in Old World culture: Arab communities took up the hookah, or water pipe, and smoking became a shared activity typically enjoyed with conversation and coffee. The hookah spread throughout Persia (present-day Iran) and into India, eventually reaching China, Southeast Asia, and many parts of Africa by the end of the 17th century.

  • water plantain (plant)

    Water plantain, (genus Alisma), any freshwater perennial herb of the genus Alisma (family Alismataceae), commonly found in lakes, ponds, and ditches. The 9 to 11 species of water plantains are primarily distributed throughout the Northern Hemisphere, 3 being native to North America. Water plantains

  • water plantain family (plant family)

    Alismataceae, the water plantain family of 113 species of freshwater flowering plants belonging to the order Alismatales and including 17 genera, the most common of which are Alisma (water plantain), Echinodorus (burhead), and Sagittaria (arrowhead). Most members of the family are native to the

  • water plantain order (plant order)

    Alismatales, arrowhead and pondweed order of flowering plants, belonging to the monocotyledon (monocot) group, whose species have a single seed leaf. Most of the some 4,500 species are aquatic and grow submersed or partially exposed to the air in marshes and other freshwater and marine habitats,

  • water pollination (pollination)

    Ceratophyllales: …unusual in that they have underwater pollination. When the male flowers are mature, the individual anthers break off and settle through the water until they reach a groove near the stigma of a female flower, leading to pollination.

  • water pollution

    Water pollution, the release of substances into subsurface groundwater or into lakes, streams, rivers, estuaries, and oceans to the point where the substances interfere with beneficial use of the water or with the natural functioning of ecosystems. In addition to the release of substances, such as

  • water polo (sport)

    Water polo, sport played in a swimming pool by teams of seven with a buoyant ball resembling an association football (soccer ball). The game was originally called “football-in-the-water,” and indeed it is more like association football and basketball than polo, the name of the sport coming from an

  • water poppy (plant)

    Hydrocleys: The water poppy (Hydrocleys nymphoides), with yellow flowers about 5 cm (2 inches) across, is the only cultivated species and is often grown in ponds and aquariums.

  • water possum (marsupial)

    Water opossum, (Chironectes minimus), a semiaquatic, web-footed marsupial (family Didelphidae, subfamily Didelphinae) found along tropical rivers, streams, and lakes from Mexico to Argentina. Adults average 70 cm (28 inches) in total length and weigh up to 790 grams (1.7 pounds). A pouch is present

  • water power

    Waterpower, power produced by a stream of water as it turns a wheel or similar device. The waterwheel was probably invented in the 1st century bce, and it was widely used throughout the Middle Ages and into modern times for grinding grain, operating bellows for furnaces, and other purposes. The

  • water pump (engineering)

    cooling system: …from the engine; (3) a water pump, usually of the centrifugal type, to circulate the liquid through the system; (4) a thermostat to control temperature by varying the amount of liquid going to the radiator; and (5) a fan to draw fresh air through the radiator.

  • water purification (public health)

    Water purification, process by which undesired chemical compounds, organic and inorganic materials, and biological contaminants are removed from water. That process also includes distillation (the conversion of a liquid into vapour to condense it back to liquid form) and deionization (ion removal

  • water rail (bird)

    Water rail, (Rallus aquaticus), slender marsh bird of the family Rallidae (order Gruiformes), native to most of Europe and Asia. Its length is about 28 cm (11 inches), and it has a moderately long beak. The sides of the bird have black and white bands. The name water rail also is used as a general

  • water rat (rodent)

    Water rat, any of 18 species of amphibious carnivorous rodents. They exhibit many adaptations associated with hunting in water for food and burrowing along streams, rivers, and lakes. The eyes are small, the nostrils can be closed to keep water out, and the external portion of the ears is either

  • water reed (plant)

    reed: …common, or water, reed (Phragmites australis) occurs along the margins of lakes, fens, marshes, and streams from the Arctic to the tropics. It is a broad-leafed grass, about 1.5 to 5 metres (5 to 16.5 feet) tall, with feathery flower clusters and stiff, smooth stems. Other plants of the…

  • water refining (food processing)

    fat and oil processing: Water refining: Water refining, usually called degumming, consists of treating the natural oil with a small amount of water, followed by centrifugal separation. The process is applied to many oils that contain phospholipids in significant amounts. Since the separated phospholipids are rather waxy or gummy solids, the term degumming was quite…

  • water resource

    Water resource, any of the entire range of natural waters that occur on the Earth, regardless of their state (i.e., vapour, liquid, or solid) and that are of potential use to humans. Of these, the resources most available for use are the waters of the oceans, rivers, and lakes; other available

  • Water Resources Development Act (1999, United States)

    South Dakota: South Dakota in the 21st century: The Water Resources Development Act of 1999 initiated the return of some of the areas along the Missouri River reservoirs to the tribes, but the final compensation amount for damage awarded to the Sioux has not been determined. The Missouri River Protection and Improvement Act was…

  • water retting (fibre-separation process)

    retting: In water retting, the most widely practiced method, bundles of stalks are submerged in water. The water, penetrating to the central stalk portion, swells the inner cells, bursting the outermost layer, thus increasing absorption of both moisture and decay-producing bacteria. Retting time must be carefully judged;…

  • water rice (plant)

    Wild rice, (genus Zizania), genus of four species of coarse grasses of the family Poaceae, the grain of which is sometimes grown as a delicacy. Despite their name, the plants are not related to true rice (Oryza sativa). Wild rice grows naturally in shallow freshwater marshes and along the shores of

  • water sapphire (mineral)

    cordierite: …Sri Lanka have been called water sapphires. Synthetic magnesium cordierite has a low thermal expansion and is used as a semirefractory material because of its resistance to thermal shock.

  • water scarcity (natural resource)

    Water scarcity, insufficient freshwater resources to meet the human and environmental demands of a given area. Water scarcity is inextricably linked to human rights, and sufficient access to safe drinking water is a priority for global development. However, given the challenges of population

  • water scavenger beetle (insect)

    Water scavenger beetle, any of the approximately 3,200 species of the predominately aquatic insect superfamily Hydrophiloidea (order Coleoptera). These beetles are found swimming in marshy freshwater ponds throughout the world, especially in warm regions. Water scavenger beetles have smooth, oval,

  • water scorpion (insect)

    Water scorpion, any of the approximately 150 species of aquatic invertebrates of the family Nepidae (order Hemiptera). The water scorpion resembles a land scorpion in certain ways: it has scythelike front legs adapted for seizing prey and a long, thin, whiplike structure at its posterior end. This

  • water screw (technology)

    Archimedes screw, machine for raising water, allegedly invented by the ancient Greek scientist Archimedes for removing water from the hold of a large ship. One form consists of a circular pipe enclosing a helix and inclined at an angle of about 45 degrees to the horizontal with its lower end dipped

  • Water Seller, The (work by U Pon Nya)

    Southeast Asian arts: Burma: …of dramatic verse, and his Water Seller is noted for its comparatively realistic treatment of court life.

  • water shield (plant)

    Fanwort, any of about seven species of aquatic flowering plants constituting the genus Cabomba, of the fanwort or water-shield family (Cabombaceae), native to the New World tropics and subtropics. Water shield is also the more commonly used name for Brasenia, the only other genus of the family. The

  • water shield (plant, Brasenia schreberi)

    Water shield, (Brasenia schreberi), small purple-flowered aquatic plant of the fanwort family (Cabombaceae), found in northern ponds and still waters throughout the world, except in Europe. “Water shield” also refers to fanwort (Cabomba). Each oval, floating leaf of water shield is 5 to 10

  • water shrew (mammal)

    Water shrew, any of 12 species of amphibious shrews that have a broad, fleshy muzzle, large chest, and long hind legs and digits. Most water shrews live in montane habitats and forage in clear, cold streams and small rivers. They use all four feet to swim, but most of the propulsive force comes

  • water skiing (sport)

    Waterskiing, planing over the surface of the water on broad skilike runners while being towed by a motorboat moving at least 24 km/hr (15 mph). The skier holds onto a handle on a rope attached to the rear of the boat and leans slightly backward. Water skis are made of wood, aluminum, fibreglass, or

  • water snake (reptile)

    Water snake, (subfamily Natricinae), any of about 200 species of semiaquatic snakes belonging to 38 genera (family Colubridae). Water snakes feed in or near water, and some leave aquatic environments only to bask in the sun or breed. Water snakes are characterized by stout bodies with strongly

  • water snowflake (plant)

    Menyanthaceae: …for its fringed water lily, water snowflake, and floating heart, comprises submerged plants with buried rootstalks and floating leaves. Most species bear yellow or white flowers, and many are popular aquarium plants. The genera Liparophyllum and Nephrophyllidium both contain a single species, while Villarsia is larger but not well known.

  • water softener

    Water softener, device for removing calcium and magnesium from water; water so treated will not form insoluble scale in pipes and tanks and will not form a precipitate with soaps or interfere with other cleaners. Water softeners usually consist of zeolite or an ion-exchange resin (q.v.) in a tank

  • water softening (chemistry)

    hard water: Water is softened on a large scale by the addition of just enough lime to precipitate the calcium as carbonate and the magnesium as hydroxide, whereupon sodium carbonate is added to remove the remaining calcium salts. In areas where the water is hard, home water…

  • water soldier (plant)

    Hydrocharitaceae: The water soldier (Stratiotes aloides) bears rosettes of tough sharp-edged leaves that float in summer but sink and decay in the autumn. Vallisneria spiralis and V. americana are two eelgrasses commonly used as aquarium plants. Turtle grass (Thalassia species) is often washed ashore in such quantities…

  • water solubility (chemistry)

    alcohol: Physical properties of alcohols: …is referred to as a hydrophilic (“water-loving”) group, because it forms hydrogen bonds with water and enhances the solubility of an alcohol in water. Methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and t-butyl alcohol are all miscible with water. Alcohols with higher molecular weights tend to be less water-soluble, because the…

  • water spangle (fern)

    fern: Annotated classification: …Azolla (about 6 species) and Salvinia (about 10 species), of floating aquatics, distributed nearly worldwide but most diverse in the tropics. Family Marsileaceae (clover ferns) Plants heterosporous; rhizomes long-creeping, slender, glabrous or hairy; leaves with two or four leaflets at the petiole tip or lacking a blade altogether, the venation…

  • water spaniel (breed of dog)

    curly-coated retriever: Developed in England from water spaniels and retrievers, it is one of the oldest retriever breeds, first exhibited in the United Kingdom in 1860. Its distinctive coat is either black or liver, covering the dog in short, tight curls except for its forehead, face, lower forelegs, and feet. It…

  • water spider (arachnid)

    Water spider, (Argyroneta aquatica), species of spider that is known for its underwater silk web, which resembles a kind of flexible diving bell. The water spider is the only species of spider known to spend its entire life underwater. It has been placed in the family Argyronetidae; however,

  • water sprite (plant)

    water fern: richardii); and water sprite (C. thalictroides). The plants are widespread in tropical and warm temperate regions around the world, and several are cultivated as aquarium plants. Although water ferns sometimes root in mud, more frequently they float on the surface of shallow water in ditches, lakes, and…

  • water star grass (plant)

    mud plantain: Water star grass (H. dubia) is widely distributed throughout North America; it has yellow star-shaped flowers.

  • water strider (insect)

    Water strider, any insect of the family Gerridae (order Heteroptera), which numbers about 350 species. Water striders, often seen running or skating in groups over the surface of a pond or stream, are slender, dark coloured, and generally more than 5 mm (0.2 inch) long. With their short front legs

  • Water Study (dance by Humphrey)

    Doris Humphrey: Water Study (1928) incorporated her theory of fall and recovery and used only nonmusical rhythms (waves and natural human breath and pulse rhythms). Drama of Motion (1930) was themeless and also performed without music; it has been described as one of the first symphonic dances…

  • water supply

    Water supply, available water provided to fulfill a particular need. If the need is domestic, industrial, or agricultural, the water must fulfill both quality and quantity requirements. Water supplies can be obtained by numerous types of engineering projects, such as wells, dams, or reservoirs. See

  • water table (hydrology)

    Water table, upper level of an underground surface in which the soil or rocks are permanently saturated with water. The water table separates the groundwater zone that lies below it from the capillary fringe, or zone of aeration, that lies above it. The water table fluctuates both with the seasons

  • water temperature (physics)

    ice in lakes and rivers: Changes in temperature structure: …the temperature structure of lake water. In most lakes during the summer, a layer of warm water of lower density lies above colder water below. In late summer, as air temperatures fall, this top layer begins to cool. After it has cooled and has reached the same density as the…

  • water torture (torture method)

    Waterboarding, method of torture in which water is poured into the nose and mouth of a victim who lies on his back on an inclined platform, with his feet above his head. As the victim’s sinus cavities and mouth fill with water, his gag reflex causes him to expel air from his lungs, leaving him

  • water transportation (water transportation)

    Shipping, transporting of goods and passengers by water. Early civilizations, which arose by waterways, depended on watercraft for transport. The Egyptians were probably the first to use seagoing vessels (c. 1500 bce); the Phoenicians, Cretans, Greeks, and Romans also all relied on waterways. In

  • water treader (insect)

    Water treader, any insect of the approximately 30 species of the family Mesoveliidae (order Heteroptera). These small, slender insects are yellowish or greenish in colour and are 5 millimetres (0.2 inch) or less in length. Mesoveliids are predaceous and are usually seen on floating vegetation or

  • water treatment (public health)

    Water purification, process by which undesired chemical compounds, organic and inorganic materials, and biological contaminants are removed from water. That process also includes distillation (the conversion of a liquid into vapour to condense it back to liquid form) and deionization (ion removal

  • water tupelo tree (plant)

    tupelo: The water tupelo (N. aquatica), also called cotton gum, or swamp gum, grows in swamps of the southeastern and Gulf of Mexico coasts and in the Mississippi River valley northward to southern Illinois. It grows in pure stands or in association with bald cypress and other…

  • water turbine

    turbine: Water turbines: Water turbines are generally divided into two categories: (1) impulse turbines used for high heads of water and low flow rates and (2) reaction turbines normally employed for heads below about 450 metres and moderate or high flow rates. These two classes include…

  • water turkey (bird)

    Darter, any of two to four species of bird of the family Anhingidae (order Pelecaniformes or Suliformes). The American species, Anhinga anhinga, is widely acknowledged as distinct, but there is debate regarding whether the darters that appear in Africa, Asia, and Oceania constitute one species (A.

  • water turtle (reptile)

    sound reception: Turtles: …that turtles of the species Pseudemys scripta, trained to withdraw their head, respond to sound over the low-frequency range, with the greatest sensitivity in the region of 200 to 640 hertz. This result is in close agreement with electrophysiological observations in which it has been found that impulses could be…

  • water vapour

    air: …gases present in variable concentrations, water vapour, ozone, carbon dioxide, sulfur dioxide, and nitrogen dioxide are of principal importance. The typical concentration ranges of these gases (in percentage by volume) are as follows:

  • water vapour feedback (atmospheric sciences)

    global warming: Water vapour feedback: …is known as the “water vapour feedback.” It is the primary reason that climate sensitivity is substantially greater than the previously stated theoretical value of 0.25 °C (0.45 °F) for each increase of 1 watt per square metre of radiative forcing.

  • water wave (water)

    Wave, a ridge or swell on the surface of a body of water, normally having a forward motion distinct from the oscillatory motion of the particles that successively compose it. The undulations and oscillations may be chaotic and random, or they may be regular, with an identifiable wavelength between

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