Misplaced Pages

#72927

57-569: Thames Head is a group of seasonal springs that arise in the Cotswolds , in the county of Gloucestershire , England . Their location is in fields near the villages of Coates and Kemble , on either side of the A433 road, about three miles south-west of the town of Cirencester . The spring water comes from the limestone aquifers of the Cotswolds. One or more of these springs are traditionally identified as

114-471: A fluid or exerted by a fluid on an immersed body". It encompasses the study of the conditions under which fluids are at rest in stable equilibrium as opposed to fluid dynamics , the study of fluids in motion. Hydrostatics is a subcategory of fluid statics , which is the study of all fluids, both compressible or incompressible, at rest. Hydrostatics is fundamental to hydraulics , the engineering of equipment for storing, transporting and using fluids. It

171-447: A fluid to the weight of fluid displaced by the object. The Roman engineer Vitruvius warned readers about lead pipes bursting under hydrostatic pressure. The concept of pressure and the way it is transmitted by fluids was formulated by the French mathematician and philosopher Blaise Pascal in 1647. The "fair cup" or Pythagorean cup , which dates from about the 6th century BC,

228-504: A heat source for thousands of years. In the 20th century, they became a renewable resource of geothermal energy for heating homes and buildings. The city of Beppu, Japan contains 2,217 hot spring well heads that provide the city with hot water. Hot springs have also been used as a source of sustainable energy for greenhouse cultivation and the growing of crops and flowers. Springs have been represented in culture through art, mythology, and folklore throughout history. The Fountain of Youth

285-474: A kind of mythic quality in that some people falsely believe that springs are always healthy sources of drinking water. They may or may not be. One must take a comprehensive water quality test to know how to use a spring appropriately, whether for a mineral bath or drinking water. Springs that are managed as spas will already have such a test. Springs are often used as sources for bottled water. When purchasing bottled water labeled as spring water one can often find

342-414: A network of cracks and fissures—openings ranging from intergranular spaces to large caves , later emerging in a spring. The forcing of the spring to the surface can be the result of a confined aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells . This is possible even if

399-530: A series of wood-block prints , Two Artists Tour the Seven Hot Springs (Sōhitsu shichitō meguri) in 1854. The Chinese city Jinan is known as "a City of Springs" (Chinese: 泉城), because of its 72 spring attractions and numerous micro spring holes spread over the city centre. Hydrostatics#Hydrostatic pressure Fluid statics or hydrostatics is the branch of fluid mechanics that studies fluids at hydrostatic equilibrium and "the pressure in

456-419: A way that the height of the jet exceeds the height of the fluid in the reservoir, apparently in violation of principles of hydrostatic pressure. The device consisted of an opening and two containers arranged one above the other. The intermediate pot, which was sealed, was filled with fluid, and several cannula (a small tube for transferring fluid between vessels) connecting the various vessels. Trapped air inside

513-479: Is a hydraulic technology whose invention is credited to the Greek mathematician and geometer Pythagoras. It was used as a learning tool. The cup consists of a line carved into the interior of the cup, and a small vertical pipe in the center of the cup that leads to the bottom. The height of this pipe is the same as the line carved into the interior of the cup. The cup may be filled to the line without any fluid passing into

570-511: Is a mythical spring which was said to restore youth to anyone who drank from it. It has been claimed that the fountain is located in St. Augustine, Florida , and was discovered by Juan Ponce de León in 1513. However, it has not demonstrated the power to restore youth, and most historians dispute the veracity of Ponce de León's discovery. Pythia, also known as the Oracle at Delphi was the high priestess of

627-479: Is also relevant to geophysics and astrophysics (for example, in understanding plate tectonics and the anomalies of the Earth's gravitational field ), to meteorology , to medicine (in the context of blood pressure ), and many other fields. Hydrostatics offers physical explanations for many phenomena of everyday life, such as why atmospheric pressure changes with altitude , why wood and oil float on water, and why

SECTION 10

#1732850988073

684-481: Is an example of an entire creek vanishing into the groundwater system. The water emerges 9 miles (14 km) away, forming some of the discharge of Mammoth Spring in Arkansas . Human activity may also affect a spring's discharge—withdrawal of groundwater reduces the water pressure in an aquifer, decreasing the volume of flow. Springs fall into three general classifications: perennial (springs that flow constantly during

741-418: Is conservative, so one can write the body force density as: ρ g = ∇ ( − ρ g z ) {\displaystyle \rho \mathbf {g} =\nabla (-\rho gz)} Then the body force density has a simple scalar potential: ϕ ( z ) = − ρ g z {\displaystyle \phi (z)=-\rho gz} And

798-576: Is greater than human body temperature, usually in the range of 45–50 °C (113–122 °F), but they can be hotter. Those springs with water cooler than body temperature but warmer than air temperature are sometimes referred to as warm springs. Hot springs or geothermal springs have been used for balneotherapy , bathing, and relaxation for thousands of years. Because of the folklore surrounding hot springs and their claimed medical value, some have become tourist destinations and locations of physical rehabilitation centers. Hot springs have been used as

855-417: Is known as the barometric formula , and may be derived from assuming the pressure is hydrostatic . If there are multiple types of molecules in the gas, the partial pressure of each type will be given by this equation. Under most conditions, the distribution of each species of gas is independent of the other species. Any body of arbitrary shape which is immersed, partly or fully, in a fluid will experience

912-1268: Is now called Pascal's law . In a fluid at rest, all frictional and inertial stresses vanish and the state of stress of the system is called hydrostatic . When this condition of V = 0 is applied to the Navier–Stokes equations for viscous fluids or Euler equations (fluid dynamics) for ideal inviscid fluid, the gradient of pressure becomes a function of body forces only. The Navier-Stokes momentum equations are: ρ D u D t = − ∇ [ p − ζ ( ∇ ⋅ u ) ] + ∇ ⋅ { μ [ ∇ u + ( ∇ u ) T − 2 3 ( ∇ ⋅ u ) I ] } + ρ g . {\displaystyle \rho {\frac {\mathrm {D} \mathbf {u} }{\mathrm {D} t}}=-\nabla [p-\zeta (\nabla \cdot \mathbf {u} )]+\nabla \cdot \left\{\mu \left[\nabla \mathbf {u} +(\nabla \mathbf {u} )^{\mathrm {T} }-{\tfrac {2}{3}}(\nabla \cdot \mathbf {u} )\mathbf {I} \right]\right\}+\rho \mathbf {g} .} By setting

969-435: Is often called Stevin's law. One could arrive to the above formula also by considering the first particular case of the equation for a conservative body force field: in fact the body force field of uniform intensity and direction: ρ g ( x , y , z ) = − ρ g k → {\displaystyle \rho \mathbf {g} (x,y,z)=-\rho g{\vec {k}}}

1026-411: Is said to result in the absorption of the minerals from the water. Some springs contain arsenic levels that exceed the 10 ppb World Health Organization (WHO) standard for drinking water . Where such springs feed rivers they can also raise the arsenic levels in the rivers above WHO limits. Water from springs is usually clear. However, some springs may be colored by the minerals that are dissolved in

1083-416: Is the general form of Stevin's law: the pressure gradient equals the body force force density field. Let us now consider two particular cases of this law. In case of a conservative body force with scalar potential ϕ {\displaystyle \phi } : ρ g = − ∇ ϕ {\displaystyle \rho \mathbf {g} =-\nabla \phi }

1140-454: The A433 road ( Fosse Way section), in a meadow called Trewsbury Mead. One of these springs is marked with an inscribed stone marker, located 360 feet (110 m) above sea level at grid reference ST980994. Below it, the springhead itself is in a hollow that has been lined with stones. The springs continue immediately south of the A433. The Ordnance Survey identifies Thames Head as the source of

1197-648: The Missouri and Arkansas Ozarks , which contain 10 known of first-magnitude; and 11 more in the Thousand Springs area along the Snake River in Idaho . The scale for spring flow is as follows: Minerals become dissolved in the water as it moves through the underground rocks . This mineral content is measured as total dissolved solids (TDS). This may give the water flavor and even carbon dioxide bubbles, depending on

SECTION 20

#1732850988073

1254-578: The Temple of Apollo . She delivered prophesies in a frenzied state of divine possession that were "induced by vapours rising from a chasm in the rock". It is believed that the vapors were emitted from the Kerna spring at Delphi. The Greek myth of Narcissus describes a young man who fell in love with his reflection in the still pool of a spring. Narcissus gazed into "an unmuddied spring, silvery from its glittering waters, which neither shepherds nor she-goats grazing on

1311-453: The absolute pressure compared to vacuum is where Δ z {\displaystyle \Delta z} is the total height of the liquid column above the test area to the surface, and p 0 is the atmospheric pressure , i.e., the pressure calculated from the remaining integral over the air column from the liquid surface to infinity. This can easily be visualized using a pressure prism . Hydrostatic pressure has been used in

1368-408: The flow velocity u = 0 {\displaystyle \mathbf {u} =\mathbf {0} } , they become simply: 0 = − ∇ p + ρ g {\displaystyle \mathbf {0} =-\nabla p+\rho \mathbf {g} } or: ∇ p = ρ g {\displaystyle \nabla p=\rho \mathbf {g} } This

1425-570: The source of the River Thames . In actuality, the source of the River Thames does not have a fixed location – rather, it changes according to the level of the groundwater in the limestone. In dry periods, the groundwater level falls, causing the Thames Head springs to dry up and the river to begin lower down in its course. In wet conditions, the groundwaters rise and the river can begin at one of

1482-474: The Stevin equation becomes: ∇ p = − ∇ ϕ {\displaystyle \nabla p=-\nabla \phi } That can be integrated to give: Δ p = − Δ ϕ {\displaystyle \Delta p=-\Delta \phi } So in this case the pressure difference is the opposite of the difference of the scalar potential associated to

1539-553: The Thames Head springs. The spring known as Lyd Well, located south of the A433 (grid reference ST989984), is often where the river starts. In 2011, the lowest recorded start of the Thames was just upstream of Ashton Keynes , which is over six miles (ten kilometres) downstream from Thames Head. During the 2022 United Kingdom heat wave , the source dried up completely, shifting five miles (eight kilometres) downstream to Somerford Keynes . The highest springs of Thames Head are located north of

1596-523: The Thames from Thames Head to Cricklade.. The marker stone in Trewsbury Mead bears the inscription: THE CONSERVATORS OF THE RIVER THAMES 1857–1974 THIS STONE WAS PLACED HERE TO MARK THE SOURCE OF THE RIVER THAMES The source of the River Thames is disputed. The Environment Agency , the Ordnance Survey and other authorities have the source of the Thames as Thames Head. Others hold that

1653-501: The Thames on its maps and the UK's Environment Agency follows their precedent. However, there is also a long-standing alternative view that the real source of the Thames is on a different headstream entirely: at Seven Springs, Gloucestershire , the source of the River Churn , which is officially a tributary of the Thames that joins the Thames at Cricklade and which is longer than the course of

1710-477: The UK. Spring (hydrology) A spring is a natural exit point at which groundwater emerges from the aquifer and flows onto the top of the Earth's crust ( pedosphere ) to become surface water . It is a component of the hydrosphere , as well as a part of the water cycle . Springs have long been important for humans as a source of fresh water , especially in arid regions which have relatively little annual rainfall . Springs are driven out onto

1767-411: The action of a net force in the opposite direction of the local pressure gradient. If this pressure gradient arises from gravity, the net force is in the vertical direction opposite that of the gravitational force. This vertical force is termed buoyancy or buoyant force and is equal in magnitude, but opposite in direction, to the weight of the displaced fluid. Mathematically, where ρ is the density of

Thames Head - Misplaced Pages Continue

1824-478: The arteriolar end of the capillary. This pressure forces plasma and nutrients out of the capillaries and into surrounding tissues. Fluid and the cellular wastes in the tissues enter the capillaries at the venule end, where the hydrostatic pressure is less than the osmotic pressure in the vessel. Statistical mechanics shows that, for a pure ideal gas of constant temperature in a gravitational field, T , its pressure, p will vary with height, h , as where This

1881-1161: The body force. In the other particular case of a body force of constant direction along z: g = − g ( x , y , z ) k → {\displaystyle \mathbf {g} =-g(x,y,z){\vec {k}}} the generalised Stevin's law above becomes: ∂ p ∂ z = − ρ ( x , y , z ) g ( x , y , z ) {\displaystyle {\frac {\partial p}{\partial z}}=-\rho (x,y,z)g(x,y,z)} That can be integrated to give another (less-) generalised Stevin's law: p ( x , y , z ) − p 0 ( x , y ) = − ∫ 0 z ρ ( x , y , z ′ ) g ( x , y , z ′ ) d z ′ {\displaystyle p(x,y,z)-p_{0}(x,y)=-\int _{0}^{z}\rho (x,y,z')g(x,y,z')dz'} where: For water and other liquids, this integral can be simplified significantly for many practical applications, based on

1938-431: The direction of the resulting force. Thus, the pressure on a fluid at rest is isotropic ; i.e., it acts with equal magnitude in all directions. This characteristic allows fluids to transmit force through the length of pipes or tubes; i.e., a force applied to a fluid in a pipe is transmitted, via the fluid, to the other end of the pipe. This principle was first formulated, in a slightly extended form, by Blaise Pascal, and

1995-403: The fluid, g is the acceleration due to gravity, and V is the volume of fluid directly above the curved surface. In the case of a ship , for instance, its weight is balanced by pressure forces from the surrounding water, allowing it to float. If more cargo is loaded onto the ship, it would sink more into the water – displacing more water and thus receive a higher buoyant force to balance

2052-421: The following two assumptions. Since many liquids can be considered incompressible , a reasonable good estimation can be made from assuming a constant density throughout the liquid. The same assumption cannot be made within a gaseous environment. Also, since the height Δ z {\displaystyle \Delta z} of the fluid column between z and z 0 is often reasonably small compared to

2109-476: The form of a particular name, an associated legend , the attribution of healing qualities to the water through the numinous presence of its guardian spirit or of a Christian saint , or a ceremony or ritual centered on the well site. Christian legends often recount how the action of a saint caused a spring's water to flow - a familiar theme, especially in the hagiography of Celtic saints. The geothermally heated groundwater that flows from thermal springs

2166-422: The fundamental nature of fluids, a fluid cannot remain at rest under the presence of a shear stress . However, fluids can exert pressure normal to any contacting surface. If a point in the fluid is thought of as an infinitesimally small cube, then it follows from the principles of equilibrium that the pressure on every side of this unit of fluid must be equal. If this were not the case, the fluid would move in

2223-672: The mountain nor any other cattle had touched, which neither bird nor beast nor branch fallen from a tree had disturbed." (Ovid) The early 20th century American photographer, James Reuel Smith created a comprehensive series of photographs documenting the historical springs of New York City before they were capped by the city after the advent of the municipal water system. Smith later photographed springs in Europe leading to his book, Springs and Wells in Greek and Roman Literature, Their Legends and Locations (1922). The 19th century Japanese artists Utagawa Hiroshige and Utagawa Toyokuni III created

2280-731: The nature of the geology through which it passes. This is why spring water is often bottled and sold as mineral water , although the term is often the subject of deceptive advertising . Mineral water contains no less than 250 parts per million (ppm) of tds. Springs that contain significant amounts of minerals are sometimes called ' mineral springs '. (Springs without such mineral content, meanwhile, are sometimes distinguished as 'sweet springs'.) Springs that contain large amounts of dissolved sodium salts , mostly sodium carbonate , are called 'soda springs'. Many resorts have developed around mineral springs and are known as spa towns . Mineral springs are alleged to have healing properties. Soaking in them

2337-400: The outlet is in the form of a 300-foot-deep (91 m) cave. In this case the cave is used like a hose by the higher elevated recharge area of groundwater to exit through the lower elevation opening. Non-artesian springs may simply flow from a higher elevation through the earth to a lower elevation and exit in the form of a spring, using the ground like a drainage pipe. Still other springs are

Thames Head - Misplaced Pages Continue

2394-400: The pipe in the center of the cup. However, when the amount of fluid exceeds this fill line, fluid will overflow into the pipe in the center of the cup. Due to the drag that molecules exert on one another, the cup will be emptied. Heron's fountain is a device invented by Heron of Alexandria that consists of a jet of fluid being fed by a reservoir of fluid. The fountain is constructed in such

2451-422: The preservation of foods in a process called pascalization . In medicine, hydrostatic pressure in blood vessels is the pressure of the blood against the wall. It is the opposing force to oncotic pressure . In capillaries, hydrostatic pressure (also known as capillary blood pressure) is higher than the opposing “colloid osmotic pressure” in blood—a “constant” pressure primarily produced by circulating albumin—at

2508-455: The pressure difference follows another time the Stevin's law: Δ p = − Δ ϕ = ρ g Δ z {\displaystyle \Delta p=-\Delta \phi =\rho g\Delta z} The reference point should lie at or below the surface of the liquid. Otherwise, one has to split the integral into two (or more) terms with the constant ρ liquid and ρ ( z ′) above . For example,

2565-470: The radius of the Earth, one can neglect the variation of g . Under these circumstances, one can transport out of the integral the density and the gravity acceleration and the law is simplified into the formula where Δ z {\displaystyle \Delta z} is the height z − z 0 of the liquid column between the test volume and the zero reference point of the pressure. This formula

2622-430: The recharge include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the underground system from many sources including permeable earth, sinkholes, and losing streams . In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed. Grand Gulf State Park in Missouri

2679-446: The result of pressure from an underground source in the earth, in the form of volcanic or magma activity. The result can be water at elevated temperature and pressure, i.e. hot springs and geysers . The action of the groundwater continually dissolves permeable bedrock such as limestone and dolomite , creating vast cave systems. Spring discharge, or resurgence , is determined by the spring's recharge basin. Factors that affect

2736-410: The surface by various natural forces, such as gravity and hydrostatic pressure . A spring produced by the emergence of geothermally heated groundwater is known as a hot spring . The yield of spring water varies widely from a volumetric flow rate of nearly zero to more than 14,000 litres per second (490 cu ft/s) for the biggest springs. Springs are formed when groundwater flows onto

2793-400: The surface of still water is always level according to the curvature of the earth . Some principles of hydrostatics have been known in an empirical and intuitive sense since antiquity, by the builders of boats, cisterns , aqueducts and fountains . Archimedes is credited with the discovery of Archimedes' Principle , which relates the buoyancy force on an object that is submerged in

2850-459: The surface. This typically happens when the water table reaches above the surface level, or if the terrain depresses sharply. Springs may also be formed as a result of karst topography , aquifers or volcanic activity . Springs have also been observed on the ocean floor , spewing warmer, low- salinity water directly into the ocean. Springs formed as a result of karst topography create karst springs , in which ground water travels through

2907-411: The true source of the Thames is at Seven Springs, Gloucestershire , some 11 miles (18 km) farther north, and east of Gloucester . Seven Springs is officially the source of the River Churn , which is a tributary of the Thames that joins at Cricklade . As it is further from the mouth of the Thames than Thames Head, the adoption of Seven Springs as its source would make the Thames the longest river in

SECTION 50

#1732850988073

2964-454: The vessels induces a jet of water out of a nozzle, emptying all water from the intermediate reservoir. Pascal made contributions to developments in both hydrostatics and hydrodynamics. Pascal's Law is a fundamental principle of fluid mechanics that states that any pressure applied to the surface of a fluid is transmitted uniformly throughout the fluid in all directions, in such a way that initial variations in pressure are not changed. Due to

3021-594: The water test for that spring on the website of the company selling it. Springs have been used as sources of water for gravity-fed irrigation of crops. Indigenous people of the American Southwest built spring-fed acequias that directed water to fields through canals. The Spanish missionaries later used this method. A sacred spring, or holy well, is a small body of water emerging from underground and revered in some religious context: Christian and/or pagan and/or other. The lore and mythology of ancient Greece

3078-487: The water. For instance, water heavy with iron or tannins will have an orange color. In parts of the United States a stream carrying the outflow of a spring to a nearby primary stream may be called a spring branch , spring creek , or run. Groundwater tends to maintain a relatively long-term average temperature of its aquifer; so flow from a spring may be cooler than other sources on a summer day, but remain unfrozen in

3135-543: The winter. The cool water of a spring and its branch may harbor species such as certain trout that are otherwise ill-suited to a warmer local climate . Springs have been used for a variety of human needs - including drinking water, domestic water supply, irrigation, mills , navigation, and electricity generation . Modern uses include recreational activities such as fishing, swimming, and floating; therapy ; water for livestock; fish hatcheries; and supply for bottled mineral water or bottled spring water. Springs have taken on

3192-569: The year); intermittent (temporary springs that are active after rainfall, or during certain seasonal changes); and periodic (as in geysers that vent and erupt at regular or irregular intervals). Springs are often classified by the volume of the water they discharge. The largest springs are called "first-magnitude", defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet (2.8 m ) of water per second. Some locations contain many first-magnitude springs, such as Florida where there are at least 27 known to be that size;

3249-471: Was replete with sacred and storied springs—notably, the Corycian , Pierian and Castalian springs. In medieval Europe, pagan sacred sites frequently became Christianized as holy wells. The term "holy well" is commonly employed to refer to any water source of limited size (i.e., not a lake or river, but including pools and natural springs and seeps), which has some significance in local folklore . This can take

#72927