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92-418: Erosion models play critical roles in soil and water resource conservation and nonpoint source pollution assessments, including: sediment load assessment and inventory, conservation planning and design for sediment control , and for the advancement of scientific understanding. The USLE or one of its derivatives are main models used by United States government agencies to measure water erosion. The USLE

184-601: A 1 cm sample cell. Aquatic plants , algae , and other photosynthetic organisms can live in water up to hundreds of meters deep, because sunlight can reach them. Practically no sunlight reaches the parts of the oceans below 1,000 metres (3,300 ft) of depth. The refractive index of liquid water (1.333 at 20 °C (68 °F)) is much higher than that of air (1.0), similar to those of alkanes and ethanol , but lower than those of glycerol (1.473), benzene (1.501), carbon disulfide (1.627), and common types of glass (1.4 to 1.6). The refraction index of ice (1.31)

276-442: A detailed discussion regarding the nature of process-based and empirical erosion models, as well as a discussion of what they termed conceptual models , which lie somewhere between the process-based and purely empirical models. Current research effort involving erosion modeling is weighted toward the development of process-based erosion models. On the other hand, the standard model for most erosion assessment and conservation planning

368-481: A large amount of sediment transport that occurs on the surface of the earth. Deposition of transported sediment forms many types of sedimentary rocks , which make up the geologic record of Earth history . The water cycle (known scientifically as the hydrologic cycle) is the continuous exchange of water within the hydrosphere , between the atmosphere , soil water, surface water , groundwater, and plants. Water moves perpetually through each of these regions in

460-464: A middle-class culture that, while subject to variability, was nevertheless part of daily existence." Historical archaeologists have incorporated Foucauldian theories into the understanding of plantation landscapes. On plantation sites throughout the Americas , plantation owners utilized surveillance methods to restrict the behaviors of the enslaved populations. James A. Delle notes that surveillance

552-469: A novel P-factor model for Europe has been developed from the data retrieved during a statistical survey that recorded the occurrence of stone walls and grass margins in EU countries. While this is one of the first efforts to incorporate cultural landscape features into a soil erosion model on a continental scale, the authors of the study pointed out several limitations, such as the small number of surveyed points and

644-477: A property that is exploited by cetaceans and humans for communication and environment sensing ( sonar ). Metallic elements which are more electropositive than hydrogen, particularly the alkali metals and alkaline earth metals such as lithium , sodium , calcium , potassium and cesium displace hydrogen from water, forming hydroxides and releasing hydrogen. At high temperatures, carbon reacts with steam to form carbon monoxide and hydrogen. Hydrology

736-411: A slope effect chart by knowing the length and gradient of the slope. The cropping management factor (C) and conservation practices factor (P) are more difficult to obtain and must be determined empirically from plot data. They are described in soil loss ratios (C or P with / C or P without). Various techniques have emerged over the last few decades to compute the five RUSLE factors. However, determining

828-432: A social hierarchy onto the colonial landscape. Such analysis and interpretations are neo-marxist in its approach to the understanding and interpreting landscapes of the past. Stephen A. Mrozwoski has extended the conclusions drawn from the archaeological analysis of elite homes and pleasure gardens into the analysis of the developing middle and working class landscapes and ideologies among industrial communities, noting "in

920-440: A structure of rigid oxygen atoms in which hydrogen atoms flowed freely. When sandwiched between layers of graphene , ice forms a square lattice. The details of the chemical nature of liquid water are not well understood; some theories suggest that its unusual behavior is due to the existence of two liquid states. Pure water is usually described as tasteless and odorless, although humans have specific sensors that can feel

1012-412: A swimming pool when the light source is sunlight reflected from the pool's white tiles. In nature, the color may also be modified from blue to green due to the presence of suspended solids or algae. In industry, near-infrared spectroscopy is used with aqueous solutions as the greater intensity of the lower overtones of water means that glass cuvettes with short path-length may be employed. To observe

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1104-409: A theoretical basis. In the 1980s some archaeologists began to criticize the classical view of Site Catchment Analysis (De Carlos 1988). The reason was related to the lack of a general method to study archaeological territory. In 1989, Javier de Carlos said that archaeology was only able to apply geographical techniques without being able to use a procedure integrated in a method. Archaeogeography

1196-461: A variety of applications including high-temperature electrochemistry and as an ecologically benign solvent or catalyst in chemical reactions involving organic compounds. In Earth's mantle, it acts as a solvent during mineral formation, dissolution and deposition. The normal form of ice on the surface of Earth is ice I h , a phase that forms crystals with hexagonal symmetry . Another with cubic crystalline symmetry , ice I c , can occur in

1288-489: Is visibly blue due to absorption of light in the region c. 600–800 nm. The color can be easily observed in a glass of tap-water placed against a pure white background, in daylight. The principal absorption bands responsible for the color are overtones of the O–H stretching vibrations . The apparent intensity of the color increases with the depth of the water column, following Beer's law . This also applies, for example, with

1380-439: Is 917 kg/m (57.25 lb/cu ft), an expansion of 9%. This expansion can exert enormous pressure, bursting pipes and cracking rocks. In a lake or ocean, water at 4 °C (39 °F) sinks to the bottom, and ice forms on the surface, floating on the liquid water. This ice insulates the water below, preventing it from freezing solid. Without this protection, most aquatic organisms residing in lakes would perish during

1472-519: Is a goal of an archaeological research project, pollen and soil analysis can aide in landscape archaeology to accurately interpret and reconstruct landscapes of the past (Schoenwetter pg 278). Advances in survey technology have permitted the rapid and accurate analysis of wide areas, making the process an efficient way of learning more about the historic environment. Global Positioning System, remote sensing, archaeological geophysics, Total stations and digital photography, as well as GIS , have helped reduce

1564-493: Is at a temperature of 273.16 K (0.01 °C; 32.02 °F) and a pressure of 611.657 pascals (0.00604 atm; 0.0887 psi); it is the lowest pressure at which liquid water can exist. Until 2019 , the triple point was used to define the Kelvin temperature scale . The water/vapor phase curve terminates at 647.096 K (373.946 °C; 705.103 °F) and 22.064 megapascals (3,200.1 psi; 217.75 atm). This

1656-428: Is greater than the repulsion between the hydrogen atoms. The O–H bond length is about 0.096 nm. Other substances have a tetrahedral molecular structure, for example methane ( CH 4 ) and hydrogen sulfide ( H 2 S ). However, oxygen is more electronegative than most other elements, so the oxygen atom has a negative partial charge while the hydrogen atoms are partially positively charged. Along with

1748-613: Is how people comprehend their social and material spaces—it is how people understand the world around them and identify appropriate ways of conducting themselves in the many different environments they may occupy (Delle 1998:38-9). Alternatively, the terms constructed, conceptualized, and ideational have been used to describe: the constructed ways in which people engage with their environments, meanings and interactions people place onto specific landscapes, and imagined and emotional perspectives individuals place with their landscapes. Many methods used to analyze archaeological sites are relevant to

1840-487: Is important in many geological processes. Groundwater is present in most rocks , and the pressure of this groundwater affects patterns of faulting . Water in the mantle is responsible for the melt that produces volcanoes at subduction zones . On the surface of the Earth, water is important in both chemical and physical weathering processes. Water, and to a lesser but still significant extent, ice, are also responsible for

1932-402: Is inherently multidisciplinary in its approach to the study of culture, and is used by pre-historical, classic, and historic archaeologists. The key feature that distinguishes landscape archaeology from other archaeological approaches to sites is that there is an explicit emphasis on the sites' relationships between material culture, human alteration of land/cultural modifications to landscape, and

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2024-470: Is it a noble gas (and therefore is not removed from the atmosphere through chemical reactions with other elements), but comparisons between the abundances of its nine stable isotopes in the modern atmosphere reveal that the Earth lost at least one ocean of water early in its history, between the Hadean and Archean eons. Any water on Earth during the latter part of its accretion would have been disrupted by

2116-498: Is known as the critical point . At higher temperatures and pressures the liquid and vapor phases form a continuous phase called a supercritical fluid . It can be gradually compressed or expanded between gas-like and liquid-like densities; its properties (which are quite different from those of ambient water) are sensitive to density. For example, for suitable pressures and temperatures it can mix freely with nonpolar compounds , including most organic compounds . This makes it useful in

2208-413: Is lower than that of liquid water. In a water molecule, the hydrogen atoms form a 104.5° angle with the oxygen atom. The hydrogen atoms are close to two corners of a tetrahedron centered on the oxygen. At the other two corners are lone pairs of valence electrons that do not participate in the bonding. In a perfect tetrahedron, the atoms would form a 109.5° angle, but the repulsion between the lone pairs

2300-452: Is not sufficiently advanced for there to exist completely process-based models which do not include empirical aspects. The primary indicator, perhaps, for differentiating process-based from other types of erosion models is the use of the sediment continuity equation discussed below. Empirical models relate management and environmental factors directly to soil loss and/or sedimentary yields through statistical relationships. Lane et al. provided

2392-400: Is often described as indicative of a "Georgian Worldview" that became popular during the 17th and 18th centuries). Many interpretations have been advanced to explain the function of these gardens. Beginning in the mid-1700s, wealthy elites began to construct large, stately homes and neat, ordered gardens with the guise of mapping superiority and exclusive knowledge onto the landscape. Although

2484-422: Is poor at dissolving nonpolar substances. This allows it to be the " solvent of life": indeed, water as found in nature almost always includes various dissolved substances, and special steps are required to obtain chemically pure water . Water is the only common substance to exist as a solid , liquid, and gas in normal terrestrial conditions. Along with oxidane , water is one of the two official names for

2576-401: Is the empirically based USLE, and there continues to be active research and development of USLE-based erosion prediction technology. The USLE was developed from erosion plot and rainfall simulator experiments. The USLE is composed of six factors to predict the long-term average annual soil loss (A). The equation includes the rainfall erosivity factor (R), the soil erodibility factor (K),

2668-458: Is the study of the movement, distribution, and quality of water throughout the Earth. The study of the distribution of water is hydrography . The study of the distribution and movement of groundwater is hydrogeology , of glaciers is glaciology , of inland waters is limnology and distribution of oceans is oceanography . Ecological processes with hydrology are in the focus of ecohydrology . The collective mass of water found on, under, and over

2760-593: The Modified Universal Soil Loss Equation (MUSLE) continue to be used for similar purposes. The two primary types of erosion models are process-based models and empirically based models. Process-based (physically based) models mathematically describe the erosion processes of detachment, transport, and deposition and through the solutions of the equations describing those processes provide estimates of soil loss and sediment yields from specified land surface areas. Erosion science

2852-485: The Moon-forming impact (~4.5 billion years ago), which likely vaporized much of Earth's crust and upper mantle and created a rock-vapor atmosphere around the young planet. The rock vapor would have condensed within two thousand years, leaving behind hot volatiles which probably resulted in a majority carbon dioxide atmosphere with hydrogen and water vapor . Afterward, liquid water oceans may have existed despite

Universal Soil Loss Equation - Misplaced Pages Continue

2944-557: The chemical formula H 2 O . It is a transparent, tasteless, odorless, and nearly colorless chemical substance . It is the main constituent of Earth 's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent ). It is vital for all known forms of life , despite not providing food energy or organic micronutrients . Its chemical formula, H 2 O , indicates that each of its molecules contains one oxygen and two hydrogen atoms , connected by covalent bonds . The hydrogen atoms are attached to

3036-432: The elements hydrogen and oxygen by passing an electric current through it—a process called electrolysis . The decomposition requires more energy input than the heat released by the inverse process (285.8 kJ/ mol , or 15.9 MJ/kg). Liquid water can be assumed to be incompressible for most purposes: its compressibility ranges from 4.4 to 5.1 × 10  Pa in ordinary conditions. Even in oceans at 4 km depth, where

3128-529: The molar volumes of the liquid and solid phases, and L f {\displaystyle L_{\text{f}}} is the molar latent heat of melting. In most substances, the volume increases when melting occurs, so the melting temperature increases with pressure. However, because ice is less dense than water, the melting temperature decreases. In glaciers, pressure melting can occur under sufficiently thick volumes of ice, resulting in subglacial lakes . The Clausius-Clapeyron relation also applies to

3220-449: The topographic factors (L and S), and the cropping management factors (C and P). The equation takes the simple product form: The USLE has another concept of experimental importance, the unit plot concept. The unit plot is defined as the standard plot condition to determine the soil's erodibility . These conditions are when the LS factor = 1 (slope = 9% and length = 22.1 m (72.6 ft) where

3312-511: The water cycle consisting of the following transfer processes: Landscape archaeology Landscape archaeology , previously known as total archaeology is a sub-discipline of archaeology and archaeological theory . It studies the ways in which people in the past constructed and used the environment around them. It is also known as archaeogeography (from the Greek ἀρχαίος "ancient", and γεωγραφία "earth study"). Landscape archaeology

3404-449: The water cycle of evaporation , transpiration ( evapotranspiration ), condensation , precipitation, and runoff , usually reaching the sea. Water plays an important role in the world economy . Approximately 70% of the fresh water used by humans goes to agriculture . Fishing in salt and fresh water bodies has been, and continues to be, a major source of food for many parts of the world, providing 6.5% of global protein. Much of

3496-594: The Baroque and Renaissance styles were out of date by the time elites in the United States employed them, this was intentionally done to communicate a knowledge and appreciation of British history that few within the community would have access to. Archaeologists have concluded that the symmetrical, geometric, designs of garden-scapes adopted by colonists in the mid eighteenth to nineteenth centuries made use of "...converging and diverging lines of sight to manipulate

3588-465: The Boott Mill boardinghouses and tenements that housed workers revealed that these yards mainly served practical functions and were not primarily used to grow foodstuffs, and may not have served an integral part in the daily lives of the low-wage workers hired (99–100). Mrozowski also argues that yards also represented social distance and distinctiveness between socio-economic classes of people, due to

3680-444: The Earth was younger and less massive , water would have been lost to space more easily. Lighter elements like hydrogen and helium are expected to leak from the atmosphere continually, but isotopic ratios of heavier noble gases in the modern atmosphere suggest that even the heavier elements in the early atmosphere were subject to significant losses. In particular, xenon is useful for calculations of water loss over time. Not only

3772-538: The Indo-European root, with Greek ύδωρ ( ýdor ; from Ancient Greek ὕδωρ ( hýdōr ), whence English ' hydro- ' ), Russian вода́ ( vodá ), Irish uisce , and Albanian ujë . One factor in estimating when water appeared on Earth is that water is continually being lost to space. H 2 O molecules in the atmosphere are broken up by photolysis , and the resulting free hydrogen atoms can sometimes escape Earth's gravitational pull. When

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3864-579: The P factor has proven to be challenging as there is usually a lack of geospatial information on the specific soil conservation practices in a given region. Thus, to estimate the P factor value in the RUSLE formula, a combination of land use type and slope gradient is often used, where a lower value indicates more effective control of soil erosion. Creating field boundaries, such as stone walls, hedgerows, earth banks, and lynchets, effectively prevented or reduced soil erosion in pre-industrial agriculture. Recently,

3956-471: The analysis of gardens (see Annapolis ). Archaeologists studying the aforementioned, and other colonial sites throughout the United States, have excavated the gardens of wealthy men and women in order to reconstruct and ascertain the function of these gardens in colonial life. Scholars analyzing the colonial gardens have noticed that gardens were designed in a neat and orderly fashion, displaying symmetry and inspired by Baroque and Renaissance styles (this style

4048-536: The analysis of cultural identities that developed among social and racial groups. It has been argued that the existence and continued use of yard spaces among Black Americans (along with other African-derived practices observed in the Americas) is proof of a distinct, new world, cultural identity. One feature that appears to be widespread throughout the African diaspora is the significant importance of yard spaces in

4140-526: The analysis of landscapes. The archaeology of landscapes incorporates multiple research methods into its analysis in order to ensure that multiple sources of information are gathered; allowing for a sound interpretation of the site in question. These methods include pollen analysis , Geographic Information Systems , soil sampling, faunal analysis, ground penetrating radar, archival data (including maps and census data), and of course archaeological excavation methods. Pollen, soil, faunal, and floral analysis allows

4232-465: The archaeological sites. Some years later, in the 1970s, spatial archaeology was created, based on the use of several tools taken from 1960s English Human Geography that was focus on the study of location interdependence. Some archaeologists use these geographical techniques (Hodder & Orton 1976; Hodder 1977, 1978; Clarke 1977 ). But these techniques were only used in isolated contexts. They did not fully constitute an archaeological method and lacked

4324-500: The archaeologist to understand the natural vegetation of an area, vegetation that was actively grown by area settlers, and the animal life that also lived in the area. An understanding of the plant and animal life specific to an area can lead to, for example, an analysis of the types of food available to members of the community, an understanding of the actual diet typical for a subset of a population, and site and skeletal dating. If landscape reconstruction and preservation, in particular,

4416-577: The bent structure, this gives the molecule an electrical dipole moment and it is classified as a polar molecule . Water is a good polar solvent , dissolving many salts and hydrophilic organic molecules such as sugars and simple alcohols such as ethanol . Water also dissolves many gases, such as oxygen and carbon dioxide —the latter giving the fizz of carbonated beverages, sparkling wines and beers. In addition, many substances in living organisms, such as proteins , DNA and polysaccharides , are dissolved in water. The interactions between water and

4508-537: The boiling point, but with the liquid/gas transition the vapor phase has a much lower density than the liquid phase, so the boiling point increases with pressure. Water can remain in a liquid state at high temperatures in the deep ocean or underground. For example, temperatures exceed 205 °C (401 °F) in Old Faithful , a geyser in Yellowstone National Park . In hydrothermal vents ,

4600-785: The chemical compound H 2 O ; it is also the liquid phase of H 2 O . The other two common states of matter of water are the solid phase, ice , and the gaseous phase, water vapor or steam . The addition or removal of heat can cause phase transitions : freezing (water to ice), melting (ice to water), vaporization (water to vapor), condensation (vapor to water), sublimation (ice to vapor) and deposition (vapor to ice). Water differs from most liquids in that it becomes less dense as it freezes. In 1 atm pressure, it reaches its maximum density of 999.972 kg/m (62.4262 lb/cu ft) at 3.98 °C (39.16 °F), or almost 1,000 kg/m (62.43 lb/cu ft) at almost 4 °C (39 °F). The density of ice

4692-477: The chosen interpolation technique. It has been demonstrated that landscape archaeology has the potential to fill this gap in the data about soil conservation practices using a GIS -based tool called Historic Landscape Characterisation (HLC). Starting from the assumptions that the construction of field boundaries has always represented an effective method to limit soil erosion and that the efficiency of any conservation measures to mitigate soil erosion increases with

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4784-433: The desired result. Conversely, a pressure cooker can be used to decrease cooking times by raising the boiling temperature. In a vacuum, water will boil at room temperature. On a pressure/temperature phase diagram (see figure), there are curves separating solid from vapor, vapor from liquid, and liquid from solid. These meet at a single point called the triple point , where all three phases can coexist. The triple point

4876-545: The everyday lives of African-Americans. Sidney W. Mintz, in describing the "house-and-yard pattern" among African-American peasants residing in the Caribbean , explains "…the house, particularly among poorer peasants, is not important in itself as a material representation (i.e. material culture/artifacts) of the domestic group or family". Mintz further states that while the house "…is usually used mainly for sleeping and for storing clothing and other articles of personal value"

4968-486: The force of gravity . This property is relied upon by all vascular plants , such as trees. Water is a weak solution of hydronium hydroxide—there is an equilibrium 2H 2 O ⇌ H 3 O + OH , in combination with solvation of the resulting hydronium and hydroxide ions. Pure water has a low electrical conductivity , which increases with the dissolution of a small amount of ionic material such as common salt . Liquid water can be split into

5060-479: The form of snow . The gaseous state of water is steam or water vapor . Water covers about 71% of the Earth's surface, with seas and oceans making up most of the water volume (about 96.5%). Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor , clouds (consisting of ice and liquid water suspended in air), and precipitation (0.001%). Water moves continually through

5152-450: The fundamental stretching absorption spectrum of water or of an aqueous solution in the region around 3,500 cm (2.85 μm) a path length of about 25 μm is needed. Also, the cuvette must be both transparent around 3500 cm and insoluble in water; calcium fluoride is one material that is in common use for the cuvette windows with aqueous solutions. The Raman-active fundamental vibrations may be observed with, for example,

5244-420: The incorporation of a full range of interdisciplinary specialists and the incorporation of scientific methods, such as magnetometry and pollen analysis, in the reconstruction of a site. Total archaeology aimed to understand sites in their contexts, studying landscapes as a whole and incorporating methods traditionally used by historians, geographers, geologists and anthropologists. The term "landscape archaeology"

5336-459: The increasing of the slope, a new P factor equation has been developed integrating the HLC within the RUSLE model. In a recent study, modeling landscape archaeological data in a soil loss estimation equation enables deeper reflection on how historical strategies for soil management might relate to current environmental and climate conditions. Water Water is an inorganic compound with

5428-449: The interaction between nature and culture. Human geography uses location analysis to define models for the understanding of the territorial organisation. The archaeologists Higgs and Vita-Finzi began to apply Site Catchment Analysis (SCA) in 1970s. They proposed a new approach to know how people settled in prehistoric societies. They analysed economic resources with tools taken from Human Geography, these resources were 5–10 km from

5520-572: The landscape of Spanish Colonial mission sites in California (El Presidio de San Francisco). Voss' interpretations reveal the lived trauma that is often concealed by popular, romanticized, narratives of relationships established through colonial contact between indigenous peoples and Spanish colonizers The mission landscape became physical and conceptualized space where two genders (male/female) and heterosexuality were to be explicitly expressed and reinforced. Landscape Archaeology has been useful in

5612-416: The liquid is known as boiling ). Sublimation and deposition also occur on surfaces. For example, frost is deposited on cold surfaces while snowflakes form by deposition on an aerosol particle or ice nucleus. In the process of freeze-drying , a food is frozen and then stored at low pressure so the ice on its surface sublimates. The melting and boiling points depend on pressure. A good approximation for

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5704-753: The liquid or solid state can form up to four hydrogen bonds with neighboring molecules. Hydrogen bonds are about ten times as strong as the Van der Waals force that attracts molecules to each other in most liquids. This is the reason why the melting and boiling points of water are much higher than those of other analogous compounds like hydrogen sulfide. They also explain its exceptionally high specific heat capacity (about 4.2 J /(g·K)), heat of fusion (about 333 J/g), heat of vaporization ( 2257 J/g ), and thermal conductivity (between 0.561 and 0.679 W/(m·K)). These properties make water more effective at moderating Earth's climate , by storing heat and transporting it between

5796-571: The lives of African Americans in the southern region of the United States in his book African-American Gardens and Yards in the Rural South. Westmacott provides a clear definition of the yard, defining it as a place where leisure activities and artistic expression often take place Similarly, Heath and Bennett describe the yard as a space in which "…food production and preparation, care and maintenance of animals, domestic chores, storage, recreation, and aesthetic enjoyment" often occur at. The use of

5888-1070: The long-distance trade of commodities (such as oil, natural gas, and manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating in industry and homes. Water is an excellent solvent for a wide variety of substances, both mineral and organic; as such, it is widely used in industrial processes and in cooking and washing. Water, ice, and snow are also central to many sports and other forms of entertainment, such as swimming , pleasure boating, boat racing , surfing , sport fishing , diving , ice skating , snowboarding , and skiing . The word water comes from Old English wæter , from Proto-Germanic * watar (source also of Old Saxon watar , Old Frisian wetir , Dutch water , Old High German wazzar , German Wasser , vatn , Gothic 𐍅𐌰𐍄𐍉 ( wato )), from Proto-Indo-European * wod-or , suffixed form of root * wed- ( ' water ' ; ' wet ' ). Also cognate , through

5980-504: The material, social, and cognitive. Material space is any space that is created by people either through physical means or through the establishment of definitions, descriptions and rules of what a space is reserved for and how it should be used (Delle 1998:38). Social space is what dictates a person's relationship with both others and the material space (Delle 1998:39). Social space is how one uses their material space to interact with others and navigate throughout their world. Cognitive space

6072-668: The natural environment. The study of landscape archaeology (also sometimes referred to as the archaeology of the cultural landscape ) has evolved to include how landscapes were used to create and reinforce social inequality and to announce one's social status to the community at large. The field includes with the dynamics of geohistorical objects, such as roads, walls, boundaries, trees, and land divisions. Landscape generally refers to both natural environments and environments constructed by human beings. Natural landscapes are considered to be environments that have not been altered by humans in any shape or form. Cultural landscapes, on

6164-418: The oceans and the atmosphere. The hydrogen bonds of water are around 23 kJ/mol (compared to a covalent O-H bond at 492 kJ/mol). Of this, it is estimated that 90% is attributable to electrostatics, while the remaining 10% is partially covalent. These bonds are the cause of water's high surface tension and capillary forces. The capillary action refers to the tendency of water to move up a narrow tube against

6256-538: The oceans may have always been on the Earth since the beginning of the planet's formation . Water ( H 2 O ) is a polar inorganic compound . At room temperature it is a tasteless and odorless liquid , nearly colorless with a hint of blue . The simplest hydrogen chalcogenide , it is by far the most studied chemical compound and is sometimes described as the "universal solvent" for its ability to dissolve more substances than any other liquid, though it

6348-773: The other hand, are environments that have been altered in some manner by people (including temporary structures and places, such as campsites, that are created by human beings). Among archaeologists, the term landscape can refer to the meanings and alterations people mark onto their surroundings. As such, landscape archaeology is often employed to study the human use of land over extensive periods of time. Landscape archaeology can be summed up by Nicole Branton's statement: The term space has commonly been used in place of cultural landscape to describe landscapes that are "produced or mediated by human behavior to elicit certain behaviors". Defined in this manner, archaeologists, such as Delle, have theorized space as composed of three components:

6440-488: The oxygen atom at an angle of 104.45°. In liquid form, H 2 O is also called "water" at standard temperature and pressure . Because Earth's environment is relatively close to water's triple point , water exists on Earth as a solid , a liquid , and a gas . It forms precipitation in the form of rain and aerosols in the form of fog . Clouds consist of suspended droplets of water and ice , its solid state. When finely divided, crystalline ice may precipitate in

6532-403: The particular placement, use, and overall function. "The result was a landscape that created social distance between the agents and the workers who lived only a few feet away. It also represents a significant transformation in the urban space. The ornamental yards of the agent's house and overseers' block signal an important shift in the type of urban space being produced and the manner in which it

6624-552: The plain view or line of sight of the homes of the overseer and/or plantation owner. Archaeologists have pointed out that, although home spaces are generally considered to have become increasingly gendered, it is erroneous to assume that only women occupied the private (home) sphere and men the public. For more extensive information on this topic, see Household Archaeology . Barbara Voss has done extensive archaeological work to reveal how ideas about gender , sexuality , marriage , and ethnic / racial intermarriage were mapped onto

6716-447: The plot is fallow and tillage is up and down slope and no conservation practices are applied (CP=1). In this state: A simpler method to predict K was presented by Wischmeier et al. which includes the particle size of the soil, organic matter content, soil structure and profile permeability. The soil erodibility factor K can be approximated from a nomograph if this information is known. The LS factors can easily be determined from

6808-402: The presence of water in their mouths, and frogs are known to be able to smell it. However, water from ordinary sources (including mineral water ) usually has many dissolved substances that may give it varying tastes and odors. Humans and other animals have developed senses that enable them to evaluate the potability of water in order to avoid water that is too salty or putrid . Pure water

6900-437: The pressure is 400 atm, water suffers only a 1.8% decrease in volume. The viscosity of water is about 10 Pa· s or 0.01 poise at 20 °C (68 °F), and the speed of sound in liquid water ranges between 1,400 and 1,540 metres per second (4,600 and 5,100 ft/s) depending on temperature. Sound travels long distances in water with little attenuation , especially at low frequencies (roughly 0.03 dB /km for 1 k Hz ),

6992-587: The rate of change of the melting temperature with pressure is given by the Clausius–Clapeyron relation : d T d P = T ( v L − v S ) L f {\displaystyle {\frac {dT}{dP}}={\frac {T\left(v_{\text{L}}-v_{\text{S}}\right)}{L_{\text{f}}}}} where v L {\displaystyle v_{\text{L}}} and v S {\displaystyle v_{\text{S}}} are

7084-449: The relationship between distance and focal point", making objects appear larger or further away than they really were. These optical illusions functioned to transform the home into a readily identifiable status symbol, and to mark the owners and occupants of these homes as socially distinct from others within the colonial community. Stately homes and gardens constructed by the colonial elite also served to assert authority and to naturalize

7176-413: The subunits of these biomacromolecules shape protein folding , DNA base pairing , and other phenomena crucial to life ( hydrophobic effect ). Many organic substances (such as fats and oils and alkanes ) are hydrophobic , that is, insoluble in water. Many inorganic substances are insoluble too, including most metal oxides , sulfides , and silicates . Because of its polarity, a molecule of water in

7268-488: The surface of a planet is called the hydrosphere . Earth's approximate water volume (the total water supply of the world) is 1.386 billion cubic kilometres (333 million cubic miles). Liquid water is found in bodies of water , such as an ocean, sea, lake, river, stream, canal , pond, or puddle . The majority of water on Earth is seawater . Water is also present in the atmosphere in solid, liquid, and vapor states. It also exists as groundwater in aquifers . Water

7360-537: The surface temperature of 230 °C (446 °F) due to the increased atmospheric pressure of the CO 2 atmosphere. As the cooling continued, most CO 2 was removed from the atmosphere by subduction and dissolution in ocean water, but levels oscillated wildly as new surface and mantle cycles appeared. Geological evidence also helps constrain the time frame for liquid water existing on Earth. A sample of pillow basalt (a type of rock formed during an underwater eruption)

7452-403: The temperature can exceed 400 °C (752 °F). At sea level , the boiling point of water is 100 °C (212 °F). As atmospheric pressure decreases with altitude, the boiling point decreases by 1 °C every 274 meters. High-altitude cooking takes longer than sea-level cooking. For example, at 1,524 metres (5,000 ft), cooking time must be increased by a fourth to achieve

7544-488: The time and cost involved in such work. Within the discipline of historical archaeology, specifically within the United States , landscape archaeology initially gained prominence with efforts to preserve the homes and gardens of prominent North American figures (see George Washington's Mount Vernon and Thomas Jefferson's Monticello ), the reconstruction of early colonial settlements (see Colonial Williamsburg ) and

7636-458: The upper atmosphere. As the pressure increases, ice forms other crystal structures . As of 2024, twenty have been experimentally confirmed and several more are predicted theoretically. The eighteenth form of ice, ice XVIII , a face-centred-cubic, superionic ice phase, was discovered when a droplet of water was subject to a shock wave that raised the water's pressure to millions of atmospheres and its temperature to thousands of degrees, resulting in

7728-535: The urban context economies of scale realized through spatial practice also contributed to a social landscape that between the eighteenth and early twentieth centuries was increasingly constructed along class lines" and demonstrate the ways in which the elite constructed their industrial landscapes that worked to restrict perceived amoral behaviors (e.g. drinking, smoking) and to maintain an orderly landscape. The landscape also provided an area where "values like orderliness, gentility, and abstinence were important elements of

7820-441: The winter. Water is a diamagnetic material. Though interaction is weak, with superconducting magnets it can attain a notable interaction. At a pressure of one atmosphere (atm), ice melts or water freezes (solidifies) at 0 °C (32 °F) and water boils or vapor condenses at 100 °C (212 °F). However, even below the boiling point, water can change to vapor at its surface by evaporation (vaporization throughout

7912-626: The yard as an important and integral aspect of a home appears to be an element that many west African cultures hold, which indicates that the function of the yard within African-American households may be a facet of west African cultures that was maintained in the New World, as well as a cultural aspect that aided in the development of African American identities in the Americas. Similarly, Mrozowski's study of rear yards associated with

8004-415: The yard is where "…children play, the washing is done, the family relaxes, and friends are entertained". Richard Westmacott, Barbara J. Heath and Amber Bennett have echoed Mintz's statements about the use of yards among African-Americans in their accounts of present day and past African-American communities. Richard Westmacott provides an extensive ethnographic account of the role gardens and yards play in

8096-614: Was developed in the U.S., based on soil erosion data collected beginning in the 1930s by the U.S. Department of Agriculture ( USDA ) Soil Conservation Service (now the USDA Natural Resources Conservation Service ). The model has been used for decades for purposes of conservation planning both in the United States where it originated and around the world, and has been used to help implement the United States' multibillion-dollar conservation program. The Revised Universal Soil Loss Equation (RUSLE) and

8188-472: Was first used in a book title, as a replacement for "total archaeology", in 1974, by Mick Aston and Trevor Rowley . The spatial archaeology trend was launched by Ian Hodder in 1976. It is an archaeological trend, such as ethnoarchaeology , cognitive archaeology and other archaeological approaches. Spatial archaeology was defined by Clarke in 1977. He pointed out three analysis levels: macro, micro and semi-micro (Clarke 1977: 11–15). This trend analyses

8280-453: Was often incorporated into the plantation landscape, noting "the planter class who designed the estate landscapes actively constructed plantation spaces…as an active part of their strategy of social control" and power. This was largely done through architectural techniques such as incorporating positions where panoptic views can be achieved into the construction of planters and/or overseers homes or by constructing slave villages that were in

8372-809: Was recovered from the Isua Greenstone Belt and provides evidence that water existed on Earth 3.8 billion years ago. In the Nuvvuagittuq Greenstone Belt , Quebec, Canada, rocks dated at 3.8 billion years old by one study and 4.28 billion years old by another show evidence of the presence of water at these ages. If oceans existed earlier than this, any geological evidence has yet to be discovered (which may be because such potential evidence has been destroyed by geological processes like crustal recycling ). More recently, in August 2020, researchers reported that sufficient water to fill

8464-478: Was utilized." Landscape archaeology has its origins in "total archaeology", a term used by Christopher Taylor in 1974 to describe an approach which incorporated wider disciplines, such as folklore, historical map analysis and geology, alongside excavation in the understanding of archaeological sites. In his excavations of the Neolithic enclosure at Great Wilbraham , David Clarke defined "total archaeology" as

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