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Plumb-bob
A plumb bob, plumb bob level, or plummet, is a weight, usually with a pointed tip on the bottom, suspended from a string and used as a vertical direction as a reference line, or plumb-line. It is a precursor to the spirit level and used to establish a vertical datum reference, datum. It is typically made of stone, wood, or lead, but can also be made of other metals. If it is used for decoration, it may be made of bone or ivory. The measuring instrument, instrument has been used since at least the time of ancient EgyptDenys A. Stocks. Experiments in Egyptian archaeology: stoneworking technology in Ancient Egypt'. Routledge; 2003. . p. 180. to ensure that constructions are "wikt:plumb, plumb", or vertical. It is also used in surveying, to establish the nadir (opposite of zenith) with respect to Gravity of Earth, gravity of a point in space. It is used with a variety of instruments (including Level (instrument), levels, theodolites, and tape measure, steel tapes) to set the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertical Direction
In astronomy, geography, and related sciences and contexts, a ''Direction (geometry, geography), direction'' or ''plane (geometry), plane'' passing by a given point is said to be vertical if it contains the local gravity direction at that point. Conversely, a direction, plane, or surface is said to be horizontal (or ''leveled'') if it is everywhere perpendicular to the vertical direction. In general, something that is vertical can be drawn from up to down (or down to up), such as the y-axis in the Cartesian coordinate system. Historical definition The word ''horizontal'' is derived from the Latin , which derives from the Greek , meaning 'separating' or 'marking a boundary'. The word ''vertical'' is derived from the late Latin ', which is from the same root as ''vertex'', meaning 'highest point' or more literally the 'turning point' such as in a whirlpool. Girard Desargues defined the vertical to be perpendicular to the horizon in his 1636 book ''Perspective''. Geophysical defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirit Level
A spirit level, bubble level, or simply a level, is an Measuring instrument, instrument designed to indicate whether a surface is Horizontal plane, horizontal (level) or vertical direction, vertical (plumb-bob, plumb). Two basic designs exist: ''tubular'' (or ''linear'') and ''Bull's eye level, bull's eye'' (or ''circular''). Different types of spirit levels may be used by carpenters, stonemasons, bricklayers, other building trades workers, Surveyor (surveying), surveyors, millwrights and other metalworkers, and in some Photography, photographic or Videography, videographic work. History The history of the spirit level was discussed in brief in an 1887 article appearing in ''Scientific American''. Melchisédech Thévenot, a French scientist, invented the instrument some time before February 2, 1661. This date can be established from Thevenot's correspondence with scientist Christiaan Huygens. Within a year of this date the inventor circulated details of his invention to othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Survey Marker
Survey markers, also called survey marks, survey monuments, or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying. A '' benchmark'' is a type of survey marker that indicates elevation (vertical position). Horizontal position markers used for triangulation are also known as '' triangulation stations''. ''Benchmarking'' is the hobby of "hunting" for these marks. Types All sorts of different objects, ranging from the familiar brass disks to liquor bottles, clay pots, and rock cairns, have been used over the years as survey markers. Some markers have been used to designate tripoints, or the meeting points of three or more countries. In the 19th century, these marks were often drill holes in rock ledges, crosses or triangles chiseled in rock, or copper or brass bolts sunk into bedrock. Today in the United States, the most common geodetic survey marks are cast metal disks with stamped legends on their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domes
A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a matter of controversy and there are a wide variety of forms and specialized terms to describe them. A dome can rest directly upon a rotunda wall, a drum, or a system of squinches or pendentives used to accommodate the transition in shape from a rectangular or square space to the round or polygonal base of the dome. The dome's apex may be closed or may be open in the form of an oculus, which may itself be covered with a roof lantern and cupola. Domes have a long architectural lineage that extends back into prehistory. Domes were built in ancient Mesopotamia, and they have been found in Persian, Hellenistic, Roman, and Chinese architecture in the ancient world, as well as among a number of indigenous building traditions throughout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bob (physics)
A bob is a heavy object (also called a "weight" or "mass") on the end of a pendulum found most commonly, but not exclusively, in pendulum clocks. Reason for use Although a pendulum can theoretically be any shape, any rigid object swinging on a pivot, clock pendulums are usually made of a weight or ''bob'' attached to the bottom end of a rod, with the top attached to a pivot so it can swing. The advantage of this construction is that it positions the centre of mass close to the physical end of the pendulum, farthest from the pivot. This maximizes the moment of inertia, and minimises the length of pendulum required for a given period. Shorter pendulums allow the clock case to be made smaller, and also minimize the pendulum's air resistance. Since most of the energy loss in clocks is due to air friction of the pendulum, this allows clocks to run longer on a given power source. Use in clocks Traditionally, a clock pendulum bob is a round flat disk, lens-shaped in sect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aplomb
In classical ballet Classical ballet is any of the traditional, formal styles of ballet that exclusively employ classical ballet technique. It is known for its aesthetics and rigorous technique (such as en pointe, pointe work, turnout (ballet), turnout of the legs, ..., aplomb () refers to an unwavering stability maintained during a vertical pose or movement. The word is of French origin, with "aplomb" meaning "perpendicularity", literally "according to the plummet". French ballet master Jean-Étienne Despréaux used the term in 1806 to refer to the dynamic balancing that is fundamental to all well-executed ballet positions and movements.Bernard Taper (1996) "Balanchine: A Biography", In 1887, German dance theorist Friedrich Albert Zorn analogized aplomb in dancers as "the sureness of touch of the pianist".Grammar of the Art of Dancing, Theoretical and Practical', a translation of an 1887 book by Friedrich Zorn Friedrich Zorn described aplomb in terms of both its outward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Datum
Data ( , ) are a collection of discrete or continuous value (semiotics), values that convey information, describing the quantity, qualitative property, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpretation (logic), interpreted formally. A datum is an individual value in a collection of data. Data are usually organized into structures such as table (information), tables that provide additional context and meaning, and may themselves be used as data in larger structures. Data may be Data (computer science), used as variable (research), variables in a computational process. Data may represent abstract ideas or concrete measurements. Data are commonly used in scientific research, economics, and virtually every other form of human organizational activity. Examples of data sets include price indices (such as the consumer price index), unemployment rates, literacy rates, and census data. In this context, data repr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spire
A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are typically made of stonework or brickwork, or else of timber structures with metal cladding, ceramic tiling, roof shingles, or slates on the exterior. Since towers supporting spires are usually square, square-plan spires emerge directly from the tower's walls, but octagonal spires are either built above a pyramidal transition section called a '' broach'' at the spire's base, or else free spaces around the tower's summit for decorative elements like pinnacles. The former solution is known as a ''broach spire''. Small or short spires are known as ''spikes'', ''spirelets'', or '' flèches''. Etymology This sense of the word spire is attested in English since the 1590s, ''spir'' having been used in Middle Low German since the 14t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumb Bob
A plumb bob, plumb bob level, or plummet, is a weight, usually with a pointed tip on the bottom, suspended from a string and used as a vertical direction as a reference line, or plumb-line. It is a precursor to the spirit level and used to establish a vertical datum. It is typically made of stone, wood, or lead, but can also be made of other metals. If it is used for decoration, it may be made of bone or ivory. The instrument has been used since at least the time of ancient EgyptDenys A. Stocks. Experiments in Egyptian archaeology: stoneworking technology in Ancient Egypt'. Routledge; 2003. . p. 180. to ensure that constructions are " plumb", or vertical. It is also used in surveying, to establish the nadir (opposite of zenith) with respect to gravity of a point in space. It is used with a variety of instruments (including levels, theodolites, and steel tapes) to set the instrument exactly over a fixed survey marker or to transcribe positions onto the ground for placing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tower
A tower is a tall Nonbuilding structure, structure, taller than it is wide, often by a significant factor. Towers are distinguished from guyed mast, masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting structures. Towers are specifically distinguished from buildings in that they are built not to be habitable but to serve other functions using the height of the tower. For example, the height of a clock tower improves the visibility of the clock, and the height of a tower in a fortified building such as a castle increases the visibility of the surroundings for defensive purposes. Towers may also be built for observation tower, observation, leisure, or telecommunication purposes. A tower can stand alone or be supported by adjacent buildings, or it may be a feature on top of a larger structure or building. Etymology Old English ''torr'' is from Latin ''turris'' via Old French ''tor''. The Latin term together with Greek language, Greek τύ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its Amphoterism, amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Lead compounds, Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumb Bob With String
Plumb may refer to: Arts and entertainment * ''Plumb'', a 1995 album by Jonatha Brooke & The Story * ''Plumb'' (Plumb album), 1997 * ''Plumb'' (Field Music album), 2012 * ''Plumb'' (novel series), 1978–1983 novel series by Maurice Gee * , by Romanian poet George Bacovia People * Plumb (surname) * Plumb (singer), stage name of American singer-songwriter Tiffany Arbuckle Lee (born 1975) Places in the United States * Plumb Beach, Brooklyn, New York City, New York, a beach and neighborhood * Plumb Branch, Missouri, a stream * Plumb Brook, New York Tools * Plumb bob, a type of tool * Plumb (tools), a brand of tools known for its hammers Other uses * Plumb Lane, an arterial road in Reno, Nevada * Plumb Memorial Library, a historic public library in Shelton, Connecticut See also * Plumb House (other) * Plumbing Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses piping, pipes, valves, piping and plumbing fitting, plu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
