126-411: A cup is an open-top vessel (container) used to hold liquids for drinking , typically with a flattened hemispherical shape, and often with a capacity of about 100–250 millilitres (3–8 US fl oz). Cups may be made of pottery (including porcelain ), glass , metal , wood , stone , polystyrene , plastic , lacquerware , or other materials. Normally, a cup is brought in contact with
252-423: A change in pressure at one point in a liquid is transmitted undiminished to every other part of the liquid and very little energy is lost in the form of compression. However, the negligible compressibility does lead to other phenomena. The banging of pipes, called water hammer , occurs when a valve is suddenly closed, creating a huge pressure-spike at the valve that travels backward through the system at just under
378-760: A conference in anthropology held by the Wenner-Gren Foundation, at Burg Wartenstein Castle, which it then owned in Austria, attended by the same scholars that attended the Pan African Congress, including Louis Leakey and Mary Leakey , who was delivering a pilot presentation of her typological analysis of Early Stone Age tools, to be included in her 1971 contribution to Olduvai Gorge , "Excavations in Beds I and II, 1960–1963." However, although
504-423: A container. Although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist. Most known matter in the universe is either gas (as interstellar clouds ) or plasma (as stars ). Liquid is one of the four primary states of matter , with the others being solid, gas and plasma . A liquid
630-479: A cover and a boiled leather carrying case. It once had a triangular stand which has been lost. It weighs 1.935 kilos, so was perhaps used ceremonially rather than throughout meals. Practices in many religions around the world, including the Ancient Greek and Roman religions included libations , the pouring of a small amount of liquid onto an altar, image or just onto the ground. Some shapes of cup, such as
756-436: A cover, was an important prestige piece in medieval houses that could afford them, and often used as a "welcome cup", or for toasts. The form survives in modern sporting trophies , and in the chalices of church liturgy. The 15th-century silver Lacock Cup is a rare English secular survival. These were the sort of cup offered by cup-bearers , historically often an important office in courts. The English word "cup" has meant
882-438: A dozen distinct styles of cups for drinking beer , depending on the precise variety of beer. The idea that a certain beer should be served in a cup of a certain shape may have been promulgated more for marketing purposes, but there very well may be some basis in fact behind it. Wine glasses also come in different shapes, depending on the color and style of wine that is intended to be served in them. Liquids A liquid
1008-400: A drinking vessel since at least 1000 AD . The definition of a cup is fluid, and is likely to be wider in specialist areas such as archaeology than in modern common speech. As an example, Anna Wierzbicka (1984) notes that in the 1970s the "older generation" expected a cup to be made of porcelain and have both a handle and a saucer, so that the plastic cup with neither a handle, nor a saucer,
1134-422: A fairly constant temperature, making a liquid suitable for blanching , boiling , or frying . Even higher rates of heat transfer can be achieved by condensing a gas into a liquid. At the liquid's boiling point, all of the heat energy is used to cause the phase change from a liquid to a gas, without an accompanying increase in temperature, and is stored as chemical potential energy . When the gas condenses back into
1260-459: A gas. Therefore, liquid and solid are both termed condensed matter . On the other hand, as liquids and gases share the ability to flow, they are both called fluids. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds . Like a gas, a liquid is able to flow and take the shape of a container. Unlike a gas, a liquid maintains a fairly constant density and does not disperse to fill every space of
1386-403: A given rate, such as when it is being sheared at finite velocity. A specific example is a liquid flowing through a pipe: in this case the liquid undergoes shear deformation since it flows more slowly near the walls of the pipe than near the center. As a result, it exhibits viscous resistance to flow. In order to maintain flow, an external force must be applied, such as a pressure difference between
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#17327655327081512-420: A hammerstone to obtain large and small pieces with one or more sharp edges. The original stone is called a core; the resultant pieces, flakes. Typically, but not necessarily, small pieces are detached from a larger piece, in which case the larger piece may be called the core and the smaller pieces the flakes . The prevalent usage, however, is to call all the results flakes, which can be confusing. A split in half
1638-404: A limited degree of particle mobility. As the temperature increases, the increased vibrations of the molecules causes distances between the molecules to increase. When a liquid reaches its boiling point , the cohesive forces that bind the molecules closely together break, and the liquid changes to its gaseous state (unless superheating occurs). If the temperature is decreased, the distances between
1764-433: A liquid this excess heat-energy is released at a constant temperature. This phenomenon is used in processes such as steaming . Since liquids often have different boiling points, mixtures or solutions of liquids or gases can typically be separated by distillation , using heat, cold, vacuum , pressure, or other means. Distillation can be found in everything from the production of alcoholic beverages , to oil refineries , to
1890-451: A mixture of otherwise immiscible liquids can be stabilized to form an emulsion , where one liquid is dispersed throughout the other as microscopic droplets. Usually this requires the presence of a surfactant in order to stabilize the droplets. A familiar example of an emulsion is mayonnaise , which consists of a mixture of water and oil that is stabilized by lecithin , a substance found in egg yolks . The microscopic structure of liquids
2016-782: A new Lower Paleolithic tool, the hand axe, appeared. The earliest European hand axes are assigned to the Abbevillian industry , which developed in northern France in the valley of the Somme River ; a later, more refined hand-axe tradition is seen in the Acheulian industry , evidence of which has been found in Europe, Africa, the Middle East, and Asia. Some of the earliest known hand axes were found at Olduvai Gorge (Tanzania) in association with remains of H. erectus . Alongside
2142-542: A receptacle, especially, for soup . Recipes have been published for cooking various dishes in cups in the microwave. Although mainly used for drinking, cups can also be used to store solids for pouring (e.g., sugar, flour, grains, salt). Cupping therapy uses heated cups applied to the body to raise the skin, for which a variety of health benefits are claimed. In the Western world, this is regarded as alternative medicine . Antimonial cups were made of antimony . If wine
2268-485: A rotating liquid forms a circular paraboloid and can therefore be used as a telescope . These are known as liquid-mirror telescopes . They are significantly cheaper than conventional telescopes, but can only point straight upward ( zenith telescope ). A common choice for the liquid is mercury. Quantities of liquids are measured in units of volume . These include the SI unit cubic metre (m ) and its divisions, in particular
2394-606: A separate Copper Age or Bronze Age. Moreover, the technologies included in those 'stages', as Goodwin called them, were not exactly the same. Since then, the original relative terms have become identified with the technologies of the Paleolithic and Mesolithic, so that they are no longer relative. Moreover, there has been a tendency to drop the comparative degree in favor of the positive: resulting in two sets of Early, Middle and Late Stone Ages of quite different content and chronologies. By voluntary agreement, archaeologists respect
2520-786: A time known as the Copper Age (or more technically the Chalcolithic or Eneolithic, both meaning 'copper–stone'). The Chalcolithic by convention is the initial period of the Bronze Age. The Bronze Age was followed by the Iron Age . The transition out of the Stone Age occurred between 6000 and 2500 BC for much of humanity living in North Africa and Eurasia . The first evidence of human metallurgy dates to between
2646-423: A trade show, or a city might hand out cups with slogans promoting recycling. There are companies that provide the service of printing slogans on cups. While in theory, most cups are well suited to hold drinkable liquids, hot drinks like tea are generally served in either insulated cups or porcelain teacups . Metal and glass cups can use a double wall construction with a vacuum-sealed space in-between to reduce
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#17327655327082772-605: A tree) with two flanges at the sides of an ovoid cup. These are also called "eared cups" (耳杯) and "winged goblets". A form with a flange on only one side appears in ancient Persian silver, and then later in Chinese porcelain , apparently gradually developing into a shape for brush-washers on the calligrapher's desk. Most ancient types of cup from the Americas were pottery, but around the Gulf of Mexico, Native American societies used
2898-565: A wide range of techniques derived from multiple fields. The work of archaeologists in determining the paleocontext and relative sequence of the layers is supplemented by the efforts of geologic specialists in identifying layers of rock developed or deposited over geologic time; of paleontological specialists in identifying bones and animals; of palynologists in discovering and identifying pollen, spores and plant species; of physicists and chemists in laboratories determining ages of materials by carbon-14 , potassium-argon and other methods. The study of
3024-446: Is a fluid . Unlike a solid, the molecules in a liquid have a much greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, allowing a liquid to flow while a solid remains rigid. A liquid, like a gas, displays the properties of a fluid. A liquid can flow, assume the shape of a container, and, if placed in a sealed container, will distribute applied pressure evenly to every surface in
3150-472: Is a fixed amount of energy associated with forming a surface of a given area. This quantity is a material property called the surface tension , in units of energy per unit area (SI units: J / m ). Liquids with strong intermolecular forces tend to have large surface tensions. A practical implication of surface tension is that liquids tend to minimize their surface area, forming spherical drops and bubbles unless other constraints are present. Surface tension
3276-403: Is a nearly incompressible fluid that conforms to the shape of its container but retains a nearly constant volume independent of pressure. It is one of the four fundamental states of matter (the others being solid , gas , and plasma ), and is the only state with a definite volume but no fixed shape. The density of a liquid is usually close to that of a solid, and much higher than that of
3402-535: Is associated with the remains of Neanderthal man . The earliest documented stone tools have been found in eastern Africa, manufacturers unknown, at the 3.3 million-year-old site of Lomekwi 3 in Kenya. Better known are the later tools belonging to an industry known as Oldowan , after the type site of Olduvai Gorge in Tanzania. The tools were formed by knocking pieces off a river pebble, or stones like it, with
3528-542: Is called bipolar flaking. Consequently, the method is often called "core-and-flake". More recently, the tradition has been called "small flake" since the flakes were small compared to subsequent Acheulean tools . The essence of the Oldowan is the making and often immediate use of small flakes. Another naming scheme is "Pebble Core Technology (PBC)": Pebble cores are ... artifacts that have been shaped by varying amounts of hard-hammer percussion. Various refinements in
3654-440: Is complex and historically has been the subject of intense research and debate. A few of the key ideas are explained below. Microscopically, liquids consist of a dense, disordered packing of molecules. This contrasts with the other two common phases of matter, gases and solids. Although gases are disordered, the molecules are well-separated in space and interact primarily through molecule-molecule collisions. Conversely, although
3780-436: Is considered to be a promising candidate for these applications as it is a liquid near room temperature, has low toxicity, and evaporates slowly. Liquids are sometimes used in measuring devices. A thermometer often uses the thermal expansion of liquids, such as mercury , combined with their ability to flow to indicate temperature. A manometer uses the weight of the liquid to indicate air pressure . The free surface of
3906-408: Is given by where: For a body of water open to the air, p 0 {\displaystyle p_{0}} would be the atmospheric pressure . Static liquids in uniform gravitational fields also exhibit the phenomenon of buoyancy , where objects immersed in the liquid experience a net force due to the pressure variation with depth. The magnitude of the force is equal to the weight of
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4032-437: Is important since machinery often operate over a range of temperatures (see also viscosity index ). The viscous behavior of a liquid can be either Newtonian or non-Newtonian . A Newtonian liquid exhibits a linear strain/stress curve, meaning its viscosity is independent of time, shear rate, or shear-rate history. Examples of Newtonian liquids include water, glycerin , motor oil , honey , or mercury. A non-Newtonian liquid
4158-477: Is in the nature of this boundary. If there is no distinct boundary, then the population of A suddenly stopped using the customs characteristic of A and suddenly started using those of B, an unlikely scenario in the process of evolution . More realistically, a distinct border period, the A/B transition, existed, in which the customs of A were gradually dropped and those of B acquired. If transitions do not exist, then there
4284-494: Is more likely to be called a " glass "; therefore, while a flat-bottomed cup made of paper is a "paper cup", a transparent one of very similar shape, is likely to be called a " tumbler ", or one of many terms for glasses, instead. Penelope Stock, a lexicographer , stated that cups, mugs and glasses are "near- synonyms ", although "sufficient differences" can be found that divide them into different groups. Wierzbicka and Keith Allan (in his work "On Cup", 2020) compare definitions of
4410-473: Is no equilibrium at this transition under constant pressure, so unless supercooling occurs, the liquid will eventually completely crystallize. However, this is only true under constant pressure, so that (for example) water and ice in a closed, strong container might reach an equilibrium where both phases coexist. For the opposite transition from solid to liquid, see melting . The phase diagram explains why liquids do not exist in space or any other vacuum. Since
4536-621: Is no proof of any continuity between A and B. The Stone Age of Europe is characteristically in deficit of known transitions. The 19th and early 20th-century innovators of the modern three-age system recognized the problem of the initial transition, the "gap" between the Paleolithic and the Neolithic. Louis Leakey provided something of an answer by proving that man evolved in Africa. The Stone Age must have begun there to be carried repeatedly to Europe by migrant populations. The different phases of
4662-571: Is now considered to be a facies of Acheulean , while Sangoan is a facies of Lupemban . Magosian is "an artificial mix of two different periods". Once seriously questioned, the intermediates did not wait for the next Pan African Congress two years hence, but were officially rejected in 1965 (again on an advisory basis) by Burg Wartenstein Conference #29, Systematic Investigation of the African Later Tertiary and Quaternary ,
4788-615: Is now the south-eastern US, traces of Yaupon tea containing caffeine have been found in pottery cups of an unusual shape: straight-sided, with a single thick spike as a handle near the top, opposite a slight pouring lip. In the Early Middle Ages glass remained in production in northern Europe, especially Germany, probably as a luxury material. Anglo-Saxon glass had several types of cup, most shared with continental areas, including "palm cups" with no flat bottom, claw beakers , glass horns, and different types of beaker. In
4914-805: Is of vital importance in chemistry and biology, and it is necessary for all known forms of life. Inorganic liquids include water, magma , inorganic nonaqueous solvents and many acids . Important everyday liquids include aqueous solutions like household bleach , other mixtures of different substances such as mineral oil and gasoline, emulsions like vinaigrette or mayonnaise , suspensions like blood, and colloids like paint and milk . Many gases can be liquefied by cooling, producing liquids such as liquid oxygen , liquid nitrogen , liquid hydrogen and liquid helium . Not all gases can be liquified at atmospheric pressure, however. Carbon dioxide , for example, can only be liquified at pressures above 5.1 atm . Some materials cannot be classified within
5040-435: Is one where the viscosity is not independent of these factors and either thickens (increases in viscosity) or thins (decreases in viscosity) under shear. Examples of non-Newtonian liquids include ketchup , custard , or starch solutions. The speed of sound in a liquid is given by c = K / ρ {\displaystyle c={\sqrt {K/\rho }}} where K {\displaystyle K}
5166-586: Is possible to speak of a general 'Stone Age' period for the whole of humanity, some groups never developed metal- smelting technology, and so remained in the so-called 'Stone Age' until they encountered technologically developed cultures. The term was innovated to describe the archaeological cultures of Europe. It may not always be the best in relation to regions such as some parts of the Indies and Oceania, where farmers or hunter-gatherers used stone for tools until European colonisation began. Archaeologists of
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5292-447: Is responsible for a range of other phenomena as well, including surface waves , capillary action , wetting , and ripples . In liquids under nanoscale confinement , surface effects can play a dominating role since – compared with a macroscopic sample of liquid – a much greater fraction of molecules are located near a surface. The surface tension of a liquid directly affects its wettability . Most common liquids have tensions ranging in
5418-425: Is the bulk modulus of the liquid and ρ {\displaystyle \rho } the density. As an example, water has a bulk modulus of about 2.2 GPa and a density of 1000 kg/m , which gives c = 1.5 km/s. At a temperature below the boiling point , any matter in liquid form will evaporate until reaching equilibrium with the reverse process of condensation of its vapor. At this point
5544-425: Is used to describe the period that followed the Stone Age, as well as to describe cultures that had developed techniques and technologies for working copper alloys (bronze: originally copper and arsenic, later copper and tin) into tools, supplanting stone in many uses. Stone Age artifacts that have been discovered include tools used by modern humans, by their predecessor species in the genus Homo , and possibly by
5670-648: The 6th and 5th millennia BC in the archaeological sites of the Vinča culture , including Majdanpek , Jarmovac , Pločnik , Rudna Glava in modern-day Serbia. Ötzi the Iceman , a mummy from about 3300 BC, carried with him a copper axe and a flint knife. In some regions, such as Sub-Saharan Africa , the Stone Age was followed directly by the Iron Age. The Middle East and Southeast Asian regions progressed past Stone Age technology around 6000 BC. Europe, and
5796-608: The Fauresmith and Sangoan technologies, and the Second Intermediate Period between Middle and Later, to encompass the Magosian technology and others. The chronologic basis for the definition was entirely relative. With the arrival of scientific means of finding an absolute chronology, the two intermediates turned out to be will-of-the-wisps . They were in fact Middle and Lower Paleolithic . Fauresmith
5922-662: The Neolithic , some shaped like animals, apparently just to engage the child. Many trophies take the form of a decorated cup, generally in metal. In cases such as the FIFA World Cup and the Stanley Cup , the competition itself may grow to take on the name of the trophy that is awarded to the winner. Owing to the common usage of cup-shaped trophies as prizes for the winners, a large number of national and international competitions are called "cups". For large examples,
6048-548: The Royal Gold Cup have been used for both religious and secular purposes over their history. The word "cup" is also used as a unit of capacity: the capacity of a "typical" cup, varying slightly from place to place; it is mostly used in recipes. The measuring cup , an adaptation of a simple cup, is a standard tool in cooking that has been in use at least as far back as Roman times . Apart from serving as drinking vessels, cups can be used as an alternative to bowls as
6174-624: The Stone Age and have been found at archeological sites throughout the world. A large number of the earliest cups are excavated from burials, and may have held offerings or supplies for the afterlife. Cups do not feature strongly in the earliest pottery found in most areas; the wares were thick and heavy, as were the carved stone vessels found in several early cultures. Probably cups in organic materials that have now decomposed, such as wood, bamboo and dried gourds were widely used. Large shells and birds' eggs have been used in some areas almost up to
6300-1247: The cryogenic distillation of gases such as argon , oxygen , nitrogen , neon , or xenon by liquefaction (cooling them below their individual boiling points). Liquid is the primary component of hydraulic systems, which take advantage of Pascal's law to provide fluid power . Devices such as pumps and waterwheels have been used to change liquid motion into mechanical work since ancient times. Oils are forced through hydraulic pumps , which transmit this force to hydraulic cylinders . Hydraulics can be found in many applications, such as automotive brakes and transmissions , heavy equipment , and airplane control systems. Various hydraulic presses are used extensively in repair and manufacturing, for lifting, pressing, clamping and forming. Liquid metals have several properties that are useful in sensing and actuation , particularly their electrical conductivity and ability to transmit forces (incompressibility). As freely flowing substances, liquid metals retain these bulk properties even under extreme deformation. For this reason, they have been proposed for use in soft robots and wearable healthcare devices , which must be able to operate under repeated deformation. The metal gallium
6426-500: The geologic time scale : The succession of these phases varies enormously from one region (and culture ) to another. The Paleolithic or Palaeolithic (from Greek: παλαιός, palaios , "old"; and λίθος, lithos , "stone" lit. "old stone", coined by archaeologist John Lubbock and published in 1865) is the earliest division of the Stone Age. It covers the greatest portion of humanity's time (roughly 99% of "human technological history", where "human" and "humanity" are interpreted to mean
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#17327655327086552-545: The jue , has a large pouring lip, and may be regarded as a type of jug rather than a cup. In the Christian ritual of Communion , adherents drink from a cup of wine (or a wine substitute) to commemorate the Last Supper of Jesus . A chalice is often used for this purpose. Chalices are usually handleless metal cups on stems; originally such shapes were standard secular elite drinking cups, and many examples such as
6678-522: The kylix , kantharos , skyphos , lip cup , and the breast-shaped mastos with no base. The Roman Empire used cups throughout Europe, with "goblet"-type shapes with shortish stems, or none, preferred for luxury examples in silver, like the Warren Cup , or Roman glass , such as the Lycurgus Cup in color-changing glass, or the spectacular carved-glass cage cups . By the 2nd century AD even
6804-709: The operating temperature range of the component. Oils are often used in engines, gear boxes , metalworking , and hydraulic systems for their good lubrication properties. Many liquids are used as solvents , to dissolve other liquids or solids. Solutions are found in a wide variety of applications, including paints , sealants , and adhesives . Naphtha and acetone are used frequently in industry to clean oil, grease, and tar from parts and machinery. Body fluids are water-based solutions. Surfactants are commonly found in soaps and detergents . Solvents like alcohol are often used as antimicrobials . They are found in cosmetics, inks , and liquid dye lasers . They are used in
6930-549: The plastic cup , in both disposable and permanent washable forms, and the paper cup , normally disposable. Materials such as processed bamboo have also come into use. Since cups have been an integral part of dining since time immemorial, they have become a valued part of human culture. Cups are used across a wide range of cultures and social classes . Historically, monarchs have been concerned about assassination via poisoning. To avoid this fate, they often used dedicated cups, with cup-bearers to guard them. A "divining cup"
7056-481: The rhyton is a cup that imitates their shape, to a greater or lesser degree, in metal or pottery. It was the general elite type of cup throughout the Mediterranean in the Iron Age , from Greece to Ancient Persia and beyond. Only some had feet or bases that allowed them to be rested on a flat surface. Large numbers were decorated with or as animal heads, or terminated in the figure of an animal. Other than
7182-637: The European Middle Ages the shapes of most ordinary cups were closer to mugs , tankards , and goblets rather than modern cups, in wood, pottery, or sometimes boiled leather . But the elite preferred cups with stems, and often covers, in metal, with glass a less common alternative. Large "ceremonial" or feasting cups, sometimes called grace cups or "welcome cups", and drinking horns , including ivory , with metal mounts, were important prestige pieces, typically too large to drink from all evening, so passed around or drunk from once. The name for
7308-592: The Nile valley. Consequently, they proposed a new system for Africa, the Three-stage System. Clark regarded the Three-age System as valid for North Africa; in sub-Saharan Africa, the Three-stage System was best. In practice, the failure of African archaeologists either to keep this distinction in mind, or to explain which one they mean, contributes to the considerable equivocation already present in
7434-521: The Stone Age ended in a given area. In Europe and North America, millstones were in use until well into the 20th century, and still are in many parts of the world. The terms "Stone Age", "Bronze Age", and "Iron Age" are not intended to suggest that advancements and time periods in prehistory are only measured by the type of tool material, rather than, for example, social organization , food sources exploited, adaptation to climate, adoption of agriculture, cooking, settlement , and religion. Like pottery ,
7560-407: The Stone Age has never been limited to stone tools and archaeology, even though they are important forms of evidence. The chief focus of study has always been on the society and the living people who belonged to it. Useful as it has been, the concept of the Stone Age has its limitations. The date range of this period is ambiguous, disputed, and variable, depending upon the region in question. While it
7686-649: The Stone Age thus could appear there without transitions. The burden on African archaeologists became all the greater, because now they must find the missing transitions in Africa. The problem is difficult and ongoing. After its adoption by the First Pan African Congress in 1947, the Three-Stage Chronology was amended by the Third Congress in 1955 to include a First Intermediate Period between Early and Middle, to encompass
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#17327655327087812-466: The Stone Age. In Sub-Saharan Africa, however, iron-working technologies were either invented independently or came across the Sahara from the north (see iron metallurgy in Africa ). The Neolithic was characterized primarily by herding societies rather than large agricultural societies, and although there was copper metallurgy in Africa as well as bronze smelting, archaeologists do not currently recognize
7938-432: The advent of metalworking . It therefore represents nearly 99.3% of human history. Though some simple metalworking of malleable metals, particularly the use of gold and copper for purposes of ornamentation, was known in the Stone Age, it is the melting and smelting of copper that marks the end of the Stone Age. In Western Asia , this occurred by about 3000 BC, when bronze became widespread. The term Bronze Age
8064-639: The beginning of the European Bronze Age from around 2800 BC. The Ringlemere Cup is a solid gold cup, with handle, from around 1600 BC, with the Rillaton Gold Cup one of two such cups known from England, with a handful of other locations and materials (such as the Hove amber cup ) making up the "unstable" (round-bottomed) cups in precious materials from the Bronze Age. Animal horns must often have been used as cups from very early on, and
8190-470: The cavities left by the bubbles with tremendous localized force, eroding any adjacent solid surface. In a gravitational field , liquids exert pressure on the sides of a container as well as on anything within the liquid itself. This pressure is transmitted in all directions and increases with depth. If a liquid is at rest in a uniform gravitational field, the pressure p {\displaystyle p} at depth z {\displaystyle z}
8316-459: The classical three states of matter. For example, liquid crystals (used in liquid-crystal displays ) possess both solid-like and liquid-like properties, and belong to their own state of matter distinct from either liquid or solid. Liquids are useful as lubricants due to their ability to form a thin, freely flowing layer between solid materials. Lubricants such as oil are chosen for viscosity and flow characteristics that are suitable throughout
8442-554: The container. If liquid is placed in a bag, it can be squeezed into any shape. Unlike a gas, a liquid is nearly incompressible, meaning that it occupies nearly a constant volume over a wide range of pressures; it does not generally expand to fill available space in a container but forms its own surface, and it may not always mix readily with another liquid. These properties make a liquid suitable for applications such as hydraulics . Liquid particles are bound firmly but not rigidly. They are able to move around one another freely, resulting in
8568-781: The cubic decimeter, more commonly called the litre (1 dm = 1 L = 0.001 m ), and the cubic centimetre, also called millilitre (1 cm = 1 mL = 0.001 L = 10 m ). The volume of a quantity of liquid is fixed by its temperature and pressure . Liquids generally expand when heated, and contract when cooled. Water between 0 °C and 4 °C is a notable exception. On the other hand, liquids have little compressibility . Water, for example, will compress by only 46.4 parts per million for every unit increase in atmospheric pressure (bar). At around 4000 bar (400 megapascals or 58,000 psi ) of pressure at room temperature water experiences only an 11% decrease in volume. Incompressibility makes liquids suitable for transmitting hydraulic power , because
8694-421: The cup: Many languages − including French, Italian, Polish, Russian, German − use two separate words for mugs and cups. Wierzbicka suggests that this situation is due to a slightly different functionality: the traditional cups are designed for drinking while sitting down at the table, while the mug is supposed to be used anywhere. This, in her opinion, explains all the specific features: Cups have been used since
8820-540: The decisions of the Pan-African Congress on Prehistory , which meets every four years to resolve the archaeological business brought before it. Delegates are actually international; the organization takes its name from the topic. Louis Leakey hosted the first one in Nairobi in 1947. It adopted Goodwin and Lowe's 3-stage system at that time, the stages to be called Early, Middle and Later. The problem of
8946-496: The discovery of these "Lomekwian" tools, the oldest known stone tools had been found at several sites at Gona, Ethiopia , on sediments of the paleo- Awash River , which serve to date them. All the tools come from the Busidama Formation, which lies above a disconformity , or missing layer, which would have been from 2.9 to 2.7 mya . The oldest sites discovered to contain tools are dated to 2.6–2.55 mya. One of
9072-402: The earlier partly contemporaneous genera Australopithecus and Paranthropus . Bone tools have been discovered that were used during this period as well but these are rarely preserved in the archaeological record . The Stone Age is further subdivided by the types of stone tools in use. The Stone Age is the first period in the three-age system frequently used in archaeology to divide
9198-548: The early Stone Age, when species prior to Homo may have manufactured tools. According to the age and location of the current evidence, the cradle of the genus is the East African Rift System, especially toward the north in Ethiopia , where it is bordered by grasslands . The closest relative among the other living primates , the genus Pan , represents a branch that continued on in the deep forest, where
9324-443: The ends of the pipe. The viscosity of liquids decreases with increasing temperature. Precise control of viscosity is important in many applications, particularly the lubrication industry. One way to achieve such control is by blending two or more liquids of differing viscosities in precise ratios. In addition, various additives exist which can modulate the temperature-dependence of the viscosity of lubricating oils. This capability
9450-423: The enormous variation seen in other mechanical properties, such as viscosity. The free surface of a liquid is disturbed by gravity ( flatness ) and waves ( surface roughness ). An important physical property characterizing the flow of liquids is viscosity . Intuitively, viscosity describes the resistance of a liquid to flow. More technically, viscosity measures the resistance of a liquid to deformation at
9576-400: The first to transition away from hunter-gatherer societies into the settled lifestyle of inhabiting towns and villages as agriculture became widespread . In the chronology of prehistory, the Neolithic era usually overlaps with the Chalcolithic ("Copper") era preceding the Bronze Age. The Stone Age is contemporaneous with the evolution of the genus Homo , with the possible exception of
9702-624: The food industry, in processes such as the extraction of vegetable oil . Liquids tend to have better thermal conductivity than gases, and the ability to flow makes a liquid suitable for removing excess heat from mechanical components. The heat can be removed by channeling the liquid through a heat exchanger , such as a radiator , or the heat can be removed with the liquid during evaporation . Water or glycol coolants are used to keep engines from overheating. The coolants used in nuclear reactors include water or liquid metals, such as sodium or bismuth . Liquid propellant films are used to cool
9828-731: The genus Homo ), extending from 2.5 or 2.6 million years ago, with the first documented use of stone tools by hominins such as Homo habilis , to the end of the Pleistocene around 10,000 BC. The Paleolithic era ended with the Mesolithic , or in areas with an early neolithisation , the Epipaleolithic . At sites dating from the Lower Paleolithic Period (about 2,500,000 to 200,000 years ago), simple pebble tools have been found in association with
9954-589: The grasslands of the rift, Homo erectus , the predecessor of modern humans, found an ecological niche as a tool-maker and developed a dependence on it, becoming a "tool-equipped savanna dweller". The oldest indirect evidence found of stone tool use is fossilised animal bones with tool marks; these are 3.4 million years old and were found in the Lower Awash Valley in Ethiopia. Archaeological discoveries in Kenya in 2015, identifying what may be
10080-589: The hand-axe tradition, there developed a distinct and very different stone-tool industry, based on flakes of stone: special tools were made from worked (carefully shaped) flakes of flint. In Europe, the Clactonian industry is one example of a flake tradition. The early flake industries probably contributed to the development of the Middle Paleolithic flake tools of the Mousterian industry , which
10206-477: The individual elements are solid under the same conditions (see eutectic mixture ). An example is the sodium-potassium metal alloy NaK . Other metal alloys that are liquid at room temperature include galinstan , which is a gallium-indium-tin alloy that melts at −19 °C (−2 °F), as well as some amalgams (alloys involving mercury). Pure substances that are liquid under normal conditions include water, ethanol and many other organic solvents. Liquid water
10332-504: The intermediate periods were gone, the search for the transitions continued. In 1859 Jens Jacob Worsaae first proposed a division of the Stone Age into older and younger parts based on his work with Danish kitchen middens that began in 1851. In the subsequent decades this simple distinction developed into the archaeological periods of today. The major subdivisions of the Three-age Stone Age cross two epoch boundaries on
10458-645: The journal Annals of the South African Museum . By then, the dates of the Early Stone Age, or Paleolithic , and Late Stone Age, or Neolithic ( neo = new), were fairly solid and were regarded by Goodwin as absolute. He therefore proposed a relative chronology of periods with floating dates, to be called the Earlier and Later Stone Age. The Middle Stone Age would not change its name, but it would not mean Mesolithic . The duo thus reinvented
10584-638: The late 19th and early 20th centuries CE, who adapted the three-age system to their ideas, hoped to combine cultural anthropology and archaeology in such a way that a specific contemporaneous tribe could be used to illustrate the way of life and beliefs of the people exercising a particular Stone-Age technology. As a description of people living today, the term Stone Age is controversial. The Association of Social Anthropologists discourages this use, asserting: To describe any living group as 'primitive' or 'Stone Age' inevitably implies that they are living representatives of some earlier stage of human development that
10710-416: The liquid displaced by the object, and the direction of the force depends on the average density of the immersed object. If the density is smaller than that of the liquid, the buoyant force points upward and the object floats, whereas if the density is larger , the buoyant force points downward and the object sinks. This is known as Archimedes' principle . Unless the volume of a liquid exactly matches
10836-579: The literature. There are in effect two Stone Ages, one part of the Three-age and the other constituting the Three-stage. They refer to one and the same artifacts and the same technologies, but vary by locality and time. The three-stage system was proposed in 1929 by Astley John Hilary Goodwin, a professional archaeologist, and Clarence van Riet Lowe , a civil engineer and amateur archaeologist, in an article titled "Stone Age Cultures of South Africa" in
10962-434: The loss of heat and keep outside surfaces cooler. Disposable cups are intended to be used only once. They are often used by fast-food restaurants and coffee shops to serve beverages. Institutions that provide drinking water, such as offices and hospitals, may also use disposable cups for sanitary reasons. Some styles of cups are used primarily for alcoholic beverages such as beer, wine, cocktail, and liquor. There are over
11088-420: The majority of humankind has left behind. In the 1920s, South African archaeologists organizing the stone tool collections of that country observed that they did not fit the newly detailed Three-Age System. In the words of J. Desmond Clark : It was early realized that the threefold division of culture into Stone, Bronze and Iron Ages adopted in the nineteenth century for Europe had no validity in Africa outside
11214-594: The molecules become smaller. When the liquid reaches its freezing point the molecules will usually lock into a very specific order, called crystallizing, and the bonds between them become more rigid, changing the liquid into its solid state (unless supercooling occurs). Only two elements are liquid at standard conditions for temperature and pressure : mercury and bromine . Four more elements have melting points slightly above room temperature : francium , caesium , gallium and rubidium . In addition, certain mixtures of elements are liquid at room temperature, even if
11340-508: The molecules in solids are densely packed, they usually fall into a regular structure, such as a crystalline lattice ( glasses are a notable exception). Stone Age Paleolithic Epipalaeolithic Mesolithic Neolithic The Stone Age was a broad prehistoric period during which stone was widely used to make stone tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years and ended between 4000 BC and 2000 BC, with
11466-466: The most striking circumstances about these sites is that they are from the Late Pliocene , where prior to their discovery tools were thought to have evolved only in the Pleistocene . Excavators at the locality point out that: ... the earliest stone tool makers were skilled flintknappers ... The possible reasons behind this seeming abrupt transition from the absence of stone tools to
11592-668: The mouth for drinking, distinguishing it from other tableware and drinkware forms such as jugs . They also most typically have handles , though a beaker has no handle or stem, and small bowl shapes are very common in Asia. Cups of different styles may be used for different types of liquids or other foodstuffs (e.g. teacups and measuring cups), in different situations (e.g. at water stations or in ceremonies and rituals ), or for decoration . The history of cups goes back well into prehistory , initially mostly as handle-less beakers or bowls, and they have been found in most cultures across
11718-455: The norm for cups intended for cold drinks, especially wine and beer. The "wine cup" that had been a major prestige category since classical antiquity was largely replaced by the wineglass , and cups for beer went the same way. The OED records the first dated use in English of "glass" as a term for a vessel, rather than just the material, in 1393-4. A new wave of hot drinks came to dominate
11844-532: The oldest evidence of hominin use of tools known to date, have indicated that Kenyanthropus platyops (a 3.2 to 3.5-million-year-old Pliocene hominin fossil discovered in Lake Turkana, Kenya, in 1999) may have been the earliest tool-users known. The oldest stone tools were excavated from the site of Lomekwi 3 in West Turkana , northwestern Kenya, and date to 3.3 million years old. Prior to
11970-626: The presence thereof include ... gaps in the geological record. The species that made the Pliocene tools remains unknown. Fragments of Australopithecus garhi , Australopithecus aethiopicus , and Homo , possibly Homo habilis , have been found in sites near the age of the Gona tools. In July 2018, scientists reported the discovery in China of the known oldest stone tools outside Africa, estimated at 2.12 million years old. Innovation in
12096-559: The present. Very simple single-use kulhar cups in unglazed terracotta , and sometimes unfired clay, are still used in South Asia , now mainly at tea stalls, and are very similar to those found at sites of the Bronze Age Indus Valley Civilization . The Bell Beaker culture , is an important archaeological culture named after the distinctive inverted-bell pottery beaker cups it used, marking
12222-526: The pressure is essentially zero (except on surfaces or interiors of planets and moons) water and other liquids exposed to space will either immediately boil or freeze depending on the temperature. In regions of space near the Earth, water will freeze if the sun is not shining directly on it and vaporize (sublime) as soon as it is in sunlight. If water exists as ice on the Moon, it can only exist in shadowed holes where
12348-581: The primates evolved. The rift served as a conduit for movement into southern Africa and also north down the Nile into North Africa and through the continuation of the rift in the Levant to the vast grasslands of Asia. Starting from about 4 million years ago ( mya ) a single biome established itself from South Africa through the rift, North Africa, and across Asia to modern China. This has been called "transcontinental 'savannahstan ' " recently. Starting in
12474-484: The range of cups. Chinese and Japanese cups have been shaped as small, rather wide, bowls for some 2,000 years, smaller versions of the shape used for eating and serving food. As well as the Chinese porcelain that very gradually overtook it, lacquer is a prestige material. The same shapes are typically used in East Asia for both tea and wine or sake , and when they appeared in Europe in the 16th century, this shape
12600-605: The remains of what may have been the earliest human ancestors. A somewhat more sophisticated Lower Paleolithic tradition, known as the Chopper chopping tool industry, is widely distributed in the Eastern Hemisphere. This tradition is thought to have been the work of the hominin species named Homo erectus . Although no such fossil tools have yet been found, it is believed that H. erectus probably made tools of wood and bone as well as stone. About 700,000 years ago,
12726-487: The rest of Asia became post-Stone Age societies by about 4000 BC. The proto-Inca cultures of South America continued at a Stone Age level until around 2000 BC, when gold, copper, and silver made their entrance. The peoples of the Americas notably did not develop a widespread behavior of smelting bronze or iron after the Stone Age period, although the technology existed. Stone tool manufacture continued even after
12852-505: The rhyton, ancient Greek drinking cup shapes were mostly very wide and shallow bowls, usually on short stems and with two handles, generally oriented horizontally, along the same plane as the mouth of the cup, rather than at 90 degrees to it, as in modern teacups . Survivals in ancient Greek pottery are numerous, and often brilliantly painted, but all probably were made also in silver, where survivals are extremely rare, as grave robbers did not bother with pottery. The most important shapes are
12978-486: The scientific study of the lithic reduction of the raw materials and methods used to make the prehistoric artifacts that are discovered. Much of this study takes place in the laboratory in the presence of various specialists. In experimental archaeology , researchers attempt to create replica tools, to understand how they were made. Flintknappers are craftsmen who use sharp tools to reduce flintstone to flint tool . In addition to lithic analysis, field prehistorians use
13104-587: The shells of the Horse conch for drinking cups, among other purposes. The tall, decorated and slightly waisted qiru or keru of Andean civilizations first appears in the Early Intermediate Period (100-600 AD). They seem to have been high-status objects. Maya elites drank from elaborately painted pottery beakers such as the Fenton Vase and Princeton Maya Vase with God L . In what
13230-439: The soul. Cards that feature cups are often associated with love, relationships, fears, and desires. Various cups have been designed so that drinking out of them without spilling is a challenge. These are called puzzle cups . The cup game involves rhythmically striking plastic cups. In the developed world, cups are often distributed for promotional purposes . For example, a corporation might distribute cups with their logo at
13356-460: The speed of sound. Another phenomenon caused by liquid's incompressibility is cavitation . Because liquids have little elasticity they can literally be pulled apart in areas of high turbulence or dramatic change in direction, such as the trailing edge of a boat propeller or a sharp corner in a pipe. A liquid in an area of low pressure (vacuum) vaporizes and forms bubbles, which then collapse as they enter high pressure areas. This causes liquid to fill
13482-629: The sun never shines and where the surrounding rock does not heat it up too much. At some point near the orbit of Saturn, the light from the Sun is too faint to sublime ice to water vapor. This is evident from the longevity of the ice that composes Saturn's rings. Liquids can form solutions with gases, solids, and other liquids. Two liquids are said to be miscible if they can form a solution in any proportion; otherwise they are immiscible. As an example, water and ethanol (drinking alcohol) are miscible whereas water and gasoline are immiscible. In some cases
13608-461: The technique of smelting ore is regarded as the end of the Stone Age and the beginning of the Bronze Age . The first highly significant metal manufactured was bronze , an alloy of copper and tin or arsenic , each of which was smelted separately. The transition from the Stone Age to the Bronze Age was a period during which modern people could smelt copper, but did not yet manufacture bronze,
13734-450: The tens of mJ/m , so droplets of oil, water, or glue can easily merge and adhere to other surfaces, whereas liquid metals such as mercury may have tensions ranging in the hundreds of mJ/m , thus droplets do not combine easily and surfaces may only wet under specific conditions. The surface tensions of common liquids occupy a relatively narrow range of values when exposed to changing conditions such as temperature, which contrasts strongly with
13860-732: The thrust chambers of rockets . In machining , water and oils are used to remove the excess heat generated, which can quickly ruin both the work piece and the tooling. During perspiration , sweat removes heat from the human body by evaporating. In the heating, ventilation, and air-conditioning industry (HVAC), liquids such as water are used to transfer heat from one area to another. Liquids are often used in cooking due to their excellent heat-transfer capabilities. In addition to thermal conduction, liquids transmit energy by convection. In particular, because warmer fluids expand and rise while cooler areas contract and sink, liquids with low kinematic viscosity tend to transfer heat through convection at
13986-477: The timeline of human technological prehistory into functional periods, with the next two being the Bronze Age and the Iron Age , respectively. The Stone Age is also commonly divided into three distinct periods: the earliest and most primitive being the Paleolithic era; a transitional period with finer tools known as the Mesolithic era; and the final stage known as the Neolithic era. Neolithic peoples were
14112-450: The transitions in archaeology is a branch of the general philosophic continuity problem, which examines how discrete objects of any sort that are contiguous in any way can be presumed to have a relationship of any sort. In archaeology, the relationship is one of causality . If Period B can be presumed to descend from Period A, there must be a boundary between A and B, the A–B boundary. The problem
14238-408: The two-handled form based on the ancient kantharos is very often used. The size of many means that " vase " would be a more appropriate name, but "cup" has become established. Early trophies, mostly for horse-racing , were generally more simple goblet shapes. In Tarot divination, the suit of cups is associated with the element of water and is regarded as symbolizing emotion, intuition, and
14364-472: The typology of the stone tools combined with the relative sequence of the types in various regions provide a chronological framework for the evolution of humanity and society. They serve as diagnostics of date, rather than characterizing the people or the society. Lithic analysis is a major and specialised form of archaeological investigation. It involves the measurement of stone tools to determine their typology, function and technologies involved. It includes
14490-426: The vapor will condense at the same rate as the liquid evaporates. Thus, a liquid cannot exist permanently if the evaporated liquid is continually removed. A liquid at or above its boiling point will normally boil, though superheating can prevent this in certain circumstances. At a temperature below the freezing point, a liquid will tend to crystallize , changing to its solid form. Unlike the transition to gas, there
14616-604: The very wide ancient Greek wine-cup kylix ended up via Latin as chalice , typically a handle-less goblet in metal, used in the Catholic mass , but also a secular shape. Many individual examples have served both secular and liturgical uses over their history. By the end of the Middle Ages glass was becoming a much cheaper material, and over the Early Modern Period it replaced pottery and other materials as
14742-405: The volume of its container, one or more surfaces are observed. The presence of a surface introduces new phenomena which are not present in a bulk liquid. This is because a molecule at a surface possesses bonds with other liquid molecules only on the inner side of the surface, which implies a net force pulling surface molecules inward. Equivalently, this force can be described in terms of energy: there
14868-556: The wealthy tended to prefer drinking from glass, as adding no taste to the drink. An ancient shape of cup in various parts of Eurasia was the "flanged cup" with either one or two flat horizontal strips attached to part of the top of the cup, acting as handles. These are found as grave goods in elite burials from around the Warring States Period (c. 475 to 221 BC), in Chinese lacquerware (wood coated with resin from
14994-483: The wide and shallow Greek phiale (Roman patera , more a dish than a cup) seem mainly to have been used for this, while others were used for both this and drinking. The rhyton , especially the types with a hole in the bottom, was one of many cup shapes used for libations. Libations were common at the start of informal social occasions involving drinking, where the normal cups were presumably often used. The most traditional Chinese ritual bronze vessel for libations,
15120-424: The world in a variety of shapes and materials. While simple cups have been widely spread across societies, high-status cups in expensive materials have been very important status symbols since at least the Bronze Age , and many found in burials. Modern household shapes of cup generally lack a stem, but this was not always the case. The large metal standing cup or covered cup with a base and stem , and usually
15246-412: Was considered usual to pour the hot liquid into the saucer to cool it slightly before drinking. Apart from a more shallow saucer the essential elements of these two forms in many contemporary examples have changed little since the mid-18th century. European porcelain manufacturers encouraged the development of different sizes of cup, and shapes of pot, for tea and coffee services. The 20th century brought
15372-506: Was initially used for locally-made cups for the new drinks of tea and coffee . By the early 18th century, the European taste for handles on cups, strongly evident from antiquity, reasserted itself and a single vertical handle was added to a slightly more upright Chinese-style bowl to create both the very similar forms of the Western teacup and coffee cup , as well as a saucer . This was initially rather deeper than modern saucers, as it
15498-421: Was kept in them for some hours, and then drunk, there was an emetic or laxative effect. Spa cups are special cups that are used to drink mineral or thermal water directly from a spring, developed in north-west Bohemia during the 17th century and are now part of Czech folklore . Chalices are sometimes used in heraldry, especially ecclesiastical heraldry . A Kronkåsa is a type of elaborate wooden cup which
15624-488: Was not a "real cup", while the "younger generation" made no such distinction, and used " coffee cup " or " teacup " to indicate the traditional cups. Twelve-year-olds had two different shapes of a cup in mind, one for hot liquids, one for juices. Names for different types of cups vary regionally and may overlap (in American English "cups" include " mugs "). Any transparent cup, regardless of actual composition,
15750-487: Was supposed to be able to detect poison. In the Bible , Joseph interpreted a dream for Pharaoh 's cup-bearer , and a silver divining cup played a key role in his reconciliation with his brothers . The Royal Gold Cup is an exceptionally rare survival, made before 1391 for John, Duke of Berry , a French prince, who gave it to his uncle, Charles VI of France . It is in gold, decorated with jewels and scenes in enamel, with
15876-525: Was used by the Swedish nobility during the Renaissance . Drinking from a cup is a significant step on a baby's path to becoming a toddler ; it is recommended that children switch from bottles to cups between six months and one year of age. Sippy cups are typically used for this transition. Like other cups for children, these are normally plastic cups. Special cups for infants seem to date back to
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