Information about Plumb Line
This article is about the tool. For the nuclear testing program, see Operation Plumbbob.
“Plumbline” redirects here. For other uses, see Plumbline (disambiguation).
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Plumb Bob
A plumb-bob or a plummet is a weight with a pointed tip on the bottom that is suspended from a string and used as a vertical reference line.
This instrument has been used since the time of the ancient Egyptians by bricklayers, masons, and carpenters to ensure that their constructions are "plumb", or perfectly upright. It may also be used in surveying to sight a point on the ground that is not readily visible. Small plumb bobs are included in the kits of various instruments such as levels and theodolites. They are used to set the instrument exactly over a fixed datum marker, prior to taking fresh readings.
Etymology of the name
The plumb in the name plumb-bob comes from the fact that such tools were archetypically made of lead (Latin ). The adjective plumb developed by extension.Use
Up until the modern age, on most tall structures, plumb-bobs were used to provide vertical datum lines for the building measurements. A section of the scaffolding would hold a plumb line that was centered over a datum mark on the floor. As the building proceeded upwards the plumb line would also be taken higher, still centered on the datum. Many cathedral spires, domes and towers still have brass datum marks inlaid into their floors, that signify the center of the structure above.The early skyscrapers used heavy plumb-bobs hung on wire in their lift wells. The weight would hang in a container of oil to dampen any swinging movement.
References
Operation Plumbbob was a series of nuclear tests conducted between May 28 and October 7, 1957 at the Nevada Test Site, following Operation Redwing, and preceding Operation Hardtack I.
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A plumbline was a string with a lead (Latin plumbum) weight used to provide a vertical reference line.
It may also refer to:
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It may also refer to:
- The Plumbline, a joke newspaper produced by the McMaster Engineering Society
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Measuring instruments are the means by which this translation is made. All measuring instruments are subject to varying degrees of instrument error.
Physicists use a vast range of instruments to perform their measurements.
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Physicists use a vast range of instruments to perform their measurements.
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The craft of stonemasonry has existed since the dawn of civilization - creating buildings, structures, and sculpture using stone from the earth. These materials have been used to construct many of the long-lasting, ancient monuments, artifacts, cathedrals, and cities in a wide
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theodolite is an instrument for measuring both horizontal and vertical angles, as used in triangulation networks. It is a key tool in surveying and engineering work, but theodolites have been adapted for other specialized purposes in fields like meteorology and rocket launch
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- This article describes a concept from surveying and geodesy. Datum is also the last known position of a submarine in ASW, the singular form of data, and a city in ancient Macedonia, probably on the site of the modern Kavala.
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2
(Amphoteric oxide)
Electronegativity 2.33 (scale Pauling)
Ionization energies
(more) 1st: 715.6 kJmol−1
2nd: 1450.5 kJmol−1
3rd: 3081.
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(Amphoteric oxide)
Electronegativity 2.33 (scale Pauling)
Ionization energies
(more) 1st: 715.6 kJmol−1
2nd: 1450.5 kJmol−1
3rd: 3081.
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spire is a tapering conical or pyramidal structure on the top of a building, particularly a church tower. Etymologically, the word is derived from Anglo-Saxon, so it is related to "spear," rather than the Romance languages and "spirit.
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dome is a common structural element of architecture that resembles the hollow upper half of a sphere.
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Description
Domes do not have to be perfectly spherical in cross-section, however; a section through a dome may be an ellipse...... Click the link for more information.
tower blocks. In the United States, the now-destroyed World Trade Center had the nickname the Twin Towers, a name shared with the Petronas Twin Towers in Kuala Lumpur.
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