Lead is a chemical element in the periodic table that has the symbol Pb (L. plumbum) and atomic number 82. A soft, heavy, toxic and malleable poor metal, lead is bluish white when freshly cut but tarnishes to dull gray when exposed to air. Lead is used in building construction, lead-acid batteries, bullets and shot, and is part of solder, pewter, and fusible alloys. Lead has the highest atomic number of all stable elements. (But see the article on Bismuth, which has a half life so long it can be cons ...

Including:

• Lead - Notable characteristics
• Lead - Applications
• Lead - History
• Lead - Occurrence
• Lead - Isotopes
• Lead - Precautions
• Lead - Health effects
• Lead - Language derivations
• Lead - Literature

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Lead has been used by humans for at least 7000 years, because it was (and continues to be) widespread and easy to extract, as well as easy to work with, being both highly malleable and ductile as well as easy to smelt. In the early bronze age lead was used with antimony and arsenic. Lead was mentioned in the Book of Exodus. Alchemists thought that lead was the oldest metal and associated it with the planet Saturn. Lead pipes that bear the insignia of Roman emperors are still in service and many Roman "pigs" (ingots) of lead figure in Derbysh ...

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Lead, Lead - Notable characteristics, Lead - Applications, Lead - History, Lead - Occurrence, Lead - Isotopes, Lead - Precautions, Lead - Health effects, Lead - Language derivations, Lead - Literature

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AIOD leads are Terminal equipment leads used solely to transmit automatic identified outward dialing (AIOD) data from a PBX to the public switched telephone network or to switched service networks (e.g., EPSCS), so that a vendor can provide a detailed monthly bill identifying long-distance usage by individual PBX stations, tie trunks, or the attendant. Other related archivesPBX, Terminal equipment, data, public switched telephone network

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In music, voice leading is the continuity between pitches or notes played successively in time. For example, when moving from a root position C triad or chord played C-E-G to an F triad in second inversion, played C-F-A, you might say that the middle "voice" rises from E to F while the top "voice" rises from G to A, this being a way to "lead" those voices. Instead of thinking of the two successive chords vertically as separate, we are concentrating on the "horizontal" (temporal or linear) continuity between notes. Concern for voice-leading often means a predominance of stepwise moti ...

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• Voice leading - Source

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One practical way to protect children from lead based paint and lead poisoning is to simply repaint with any modern paint and to repaint any areas where the paint peels or chips in a timely fashion. Children will be unlikely to consume any lead paint because the newly painted surface will not taste sweet. There are many laws regarding lead-based paint remediation, so you may be required to do more than repainting. In preparing the surface for painting, be aware that sanding may create undesirable lead du ...

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Lead paint, Lead paint - Lead paint in buildings, Lead paint - Lead paint in art, Lead paint - Substitutes

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Lead was first mined in Turkey about 6500 BC. A 6000- to 8000-year-old necklace was found in the ancient city site of Anatolia. Lead's easy workability, low melting point and corrosion resistance were among its attractions. Lead toxicity was first recognized as early as 2000 BC. Nikander of Colophon wrote of lead-induced anemia and colic in 250 BC. Gout, prevalent in affluent Rome, is thought to be the result of lead, or leaded, eating and drink ...

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Lead poisoning, Lead poisoning - History, Lead poisoning - Symptoms and effects, Lead poisoning - Biological role, Lead poisoning - Occurrence, Lead poisoning - Measurement, Lead poisoning - Treatment, Lead poisoning - Famous cases of lead poisoning, Lead poisoning - External link

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Pencil lead is graded by hardness: a greater percentage of clay results in a harder lead. H (harder), F, HB and B (softer) are pencils of average hardness. Pencils ranging from 2B to 9B are softer still and are used for sketching; 2H to 9H are harder than average. A common American #2 pencil is equivalent to HB. In order, the leads are (from hardest to softest) 9H | 8H | 7H | 6H | 5H | 4H | 3H | 2H | H | F | HB | B | 2B | 3B | 4B | 5B | 6B | 7B | 8B | 9B. The harder the pencil the lighter the mark, e.g. "b"s tend to a create d ...

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Pencil lead, Pencil lead - History, Pencil lead - Hardness, Pencil lead - Mechanical pencils

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Graphite was originally discovered in England after a violent storm broke some trees leaving a graphite deposit visible under the roots. Graphite was soon used to write but it was very fragile so it had to be wrapped in a string and later inserted into a perforated cedar wood stick. Early cedar pencils were made of a solid piece of wood but modern pencils are made with two halves glued together with the lead between them. The Napoleonic Wars birthed the modern graphite and clay-based pencil out of necessity. France, under naval blocka ...

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Pencil lead, Pencil lead - History, Pencil lead - Hardness, Pencil lead - Mechanical pencils

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One measure of lead in the body is the blood lead level (BLL), measured in micrograms of lead per deciliter of blood (μg/dL). Nearly everyone has a measurable BLL. The Centers for Disease Control and Prevention (CDC) states that a BLL of 10 μg/dL or above is a cause for concern. However, lead can impair development even at BLLs below 10 μg/dL. The average person has less than 10 micrograms per deciliter, or 100 parts per billion, ppb, of lead in their blood serum. People who have been exposed to an unusual amount of lead will have lead serum levels higher than 200 ppb—most clinical sympt ...

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Lead poisoning, Lead poisoning - History, Lead poisoning - Symptoms and effects, Lead poisoning - Biological role, Lead poisoning - Occurrence, Lead poisoning - Measurement, Lead poisoning - Treatment, Lead poisoning - Famous cases of lead poisoning, Lead poisoning - External link

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Lead tetroxide is prepared by calcination of lead(II) oxide in air at about 450 to 480 °C: 6 PbO + O2 → 2 Pb3O4 The resulting material is contaminated with lead(II) oxide. If a pure compoun is desired, PbO can be removed by a potassium hydroxide solution: Another method of preparation relies on annealing of lead carbonate (cerussite) in air: 6 PbCO3 + O2 → 2 Pb3See also:

Red lead, Red lead - Preparation, Red lead - Chemical properties, Red lead - Use, Red lead - Physiological effects, Red lead - Ecological issues, Red lead - Historic note

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Lead sulfide and several other lead salts are used as detection element material in various infra-red sensors. Of these, PbS (lead sulfide) is one of the oldest and most commonly used. It is used for eg. infrared detectors. When used as IR detection element material they are classified as photon detectors: this means that unlike thermal detectors (the other major type), they react directly to the photons of incoming light radiation hitting the material. Thermal detectors react only to the eventual temperature rise in the materi ...

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Lead sulfide, Lead sulfide - Applications, Lead sulfide - Safety Information, Lead sulfide - Astronomy, Lead sulfide - Physical properties

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Lead has no known biological role in the body. The toxicity comes from its ability to mimic other biologically important metals, the most notable of which are calcium, iron and zinc. Lead is able to bind to and interact with the same proteins and molecules as these metals, but after displacement, those molecules function differently and fail to carry out the same reactions, such as in producing e ...

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Lead poisoning, Lead poisoning - History, Lead poisoning - Symptoms and effects, Lead poisoning - Biological role, Lead poisoning - Occurrence, Lead poisoning - Measurement, Lead poisoning - Treatment, Lead poisoning - Famous cases of lead poisoning, Lead poisoning - External link

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When breathed in, lead tetroxide irritates lungs. In case of high dose, the victim feels metallic taste in mouth, chest pain, and abdominal pain. When ingested, it gets dissolved in the gastric acid and gets absorbed, leading to lead poisoning. High concentrations can be absorbed through skin as well; therefore it is important to keep the safety precautions when working with lead-based paint. Long-term contact with lead tetroxide may lead to accumulation of lead compounds in organism, with development of symptoms of acute lead poisoning. Chronic poisoning displays as agitation, irritability, vision disorders, hype ...

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Red lead, Red lead - Preparation, Red lead - Chemical properties, Red lead - Use, Red lead - Physiological effects, Red lead - Ecological issues, Red lead - Historic note

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With iron oxides and with elementary iron, lead tetroxide forms insoluble iron(II) and iron(III) plumbates, which is the basis of the anti-corrosive properties of lead-based paints applied to iron objects. When heated to 500 °C, it decomposes to lead(II) oxide and oxygen. At 580 °C, the reaction is complete. 2 Pb3O4 → 6 PbO + O2 Nitric acid dissolves the lead(II) oxide component, leaving behind the insoluble lead(IV) oxide: Pb3O4 + 4 HNO3 → PbO2 + 2 Pb(NOSee also:

Red lead, Red lead - Preparation, Red lead - Chemical properties, Red lead - Use, Red lead - Physiological effects, Red lead - Ecological issues, Red lead - Historic note

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Lead is located at 44°21'3" North, 103°45'57" West (44.350967, -103.765784)GR1. According to the United States Census Bureau, the city has a total area of 5.2 km² (2.0 mi²). 5.2 km² (2.0 mi²) of it is land and none of the area is covered with water. Lead has been assigned the ZIP code 57754 and the FIPS place code 36220. Lead's close proximity to Deadwood, South Dakota, often leads to the two ...

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Lead South Dakota, Lead South Dakota - Geography, Lead South Dakota - Demographics

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The leader has to communicate the direction of the movement to the follower. As, traditionally, the right hand of the man is on the natural bra line of the woman's back, this is the strongest part of her back and is the safest place for the man's hand to be, and he can easily pull her body towards him. To communicate a step forward (backward for the girl) the woman has to constantly put a little weight against the right hand of the man. When the man goes forward, and so does the hand on her shoul ...

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Lead and follow dance, Lead and follow dance - Hijacking, Lead and follow dance - Backleading, Lead and follow dance - Body lead vs arm lead, Lead and follow dance - Techniques of leading, Lead and follow dance - Recovery

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TEL is a viscous colorless liquid, produced by reacting ethyl chloride with a sodium-lead alloy. TEL has a very weak carbon-lead bond, and at the temperatures found in internal combustion engines it decomposes into lead and ethyl radicals, propagating the combustion by radical reactions. When TEL burns, it produces lead and many lead compounds (including lead oxide), which would quickly build up and destroy an engine. That is why scavengers such as ethylene dibromide and ethylene dichloride are used, which form volatile lead(I ...

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Tetra-ethyl lead, Tetra-ethyl lead - Chemistry, Tetra-ethyl lead - Uses, Tetra-ethyl lead - History

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The origin of the Sinaia lead plates is obscure. The first known mention of them was when the 200 lead plates were discovered in the warehouse of the Bucharest Museum of Antiquities in the 19th century. They were widely ignored and considered fake because they looked new, as they showed no traces of corrosion. However, renewed interest in the plates has been shown more than a century later, following the publication of a report about them by Dan Romalo in 2003. Of the 200 pieces in the collection ...

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Sinaia lead plates, Sinaia lead plates - History, Sinaia lead plates - Description, Sinaia lead plates - Language, Sinaia lead plates - Debate and authors, Sinaia lead plates - Fragments translated and adapted into English, Sinaia lead plates - External link

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Sometimes the follower steals the lead and they reverse roles for some time. This is called hijacking (or, of course, lead stealing). Hijacking requires experience and good connection, since without proper timing it may look like sloppy dancing. A signal for hijacking is typically an unusually changed (mostly, increased) stress in the connection from the follower's side. "Unusually" means more than typically required for the execution of the current step (by these partners). For a follower to hijack, they must be sure that the leader will unde ...

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Lead and follow dance, Lead and follow dance - Hijacking, Lead and follow dance - Backleading, Lead and follow dance - Body lead vs arm lead, Lead and follow dance - Techniques of leading, Lead and follow dance - Recovery

Read more here: » Lead and follow dance: Encyclopedia II - Lead and follow dance - Hijacking