Posts by Jai Ganesh

Jai Ganesh · This is Cool

2387) Blue Whale

Gist

Blue whales are the largest animals ever to live on our planet. They feed almost exclusively on krill, straining huge volumes of ocean water through their baleen plates (which hang from the roof of the mouth and work like a sieve). Some of the biggest individuals may eat up to 6 tons of krill a day.

There are an estimated 10,000 to 25,000 blue whales left in the world, with recent research indicating that the population may be increasing. The species is still classified as endangered by the IUCN Red List of Threatened Species due to historical whaling, but current threats include entanglement in fishing gear and vessel strikes.

Summary

The blue whale (Balaenoptera musculus) is a marine mammal and a baleen whale. Reaching a maximum confirmed length of 29.9–30.5 m (98–100 ft) and weighing up to 190–200 t (190–200 long tons; 210–220 short tons), it is the largest animal known to have ever existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and B. m. indica in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies.

In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. There is also evidence of year-round residencies, and partial or age- and gender-based migration. Blue whales are filter feeders; their diet consists almost exclusively of krill. They are generally solitary or gather in small groups, and have no well-defined social structure other than mother–calf bonds. Blue whales vocalize, with a fundamental frequency ranging from 8 to 25 Hz; their vocalizations may vary by region, season, behavior, and time of day. Orcas are their only natural predators.

The blue whale was abundant in nearly all the Earth's oceans until the end of the 19th century. It was hunted almost to the point of extinction by whalers until the International Whaling Commission banned all blue whale hunting in 1966. The International Union for Conservation of Nature has listed blue whales as Endangered as of 2018. Blue whales continue to face numerous man-made threats such as ship strikes, pollution, ocean noise, and climate change.

Details

A blue whale (Balaenoptera musculus) is the most massive animal ever to have lived, a species of baleen whale that weighs approximately 150 tons and may attain a length of more than 30 metres (98 feet). The largest accurately measured blue whale was a 29.5-metre female that weighed 180 metric tons (nearly 200 short [U.S.] tons), but there are reports of 33-metre catches that may have reached 200 metric tons. Their hearts, which typically weigh about 180 kg (roughly 400 pounds), are the largest of any animal.

The blue whale is a cetacean and is classified scientifically within the order Cetacea as a rorqual (family Balaenopteridae) related to the gray whale (family Eschrichtiidae) and the right whales (Balaenidae and Neobalaenidae) of the baleen whale suborder, Mysticeti.

Blue whales are blue-gray in colour with lighter gray mottling in the form of large spots, which appear as if they were dabbed on with a huge paintbrush. The lower surfaces of the flippers are lighter gray or white in some instances. The blue whale has been called the sulfur-bottom whale because of the yellowish underside of some individuals that is reminiscent of the pale yellow colour of that chemical element; this coloration is imparted by certain algae (diatoms) living on the whale’s body. The blue whale has a wide head, a small dorsal fin located near the fluke, and 80–100 long grooves running lengthwise down the throat and chest. Its mouth contains up to 800 plates of short, wide, black baleen, or “whalebone,” with thick, coarse bristles used for catching food. Females are generally larger than males, and the largest animals live in the Southern Ocean around Antarctica.

The blue whale is found alone or in small groups in all oceans, but populations in the Southern Hemisphere are much larger. In the Northern Hemisphere, blue whales can be seen regularly in the Gulf of St. Lawrence and off the coasts of Monterey, California, and Baja California, Mexico. They spend the summer in polar waters, feeding on shrimplike crustaceans called krill. During a dive, the blue whale may engage in a series of turns and 360° rolls to locate prey and rapidly reorient its body to sweep up large concentrations of krill in a single open-mouthed lunge. A single adult blue may consume as much as eight tons of krill per day. In the winter blue whales move toward the Equator to breed. After a gestation of about 12 months, one calf about 8 metres (about 26 feet) long is born in temperate waters. While nursing, calves gain up to 90 kg (about 198 pounds) per day on the rich milk of their mothers. Young are weaned after seven to eight months, when they have reached a length of about 15 metres (about 49 feet).

Once the most important of the commercially hunted baleen whales, the blue whale was greatly reduced in numbers during the first half of the 20th century. In the 1930–31 season alone the worldwide kill of blue whales exceeded 29,000. The species has been protected from commercial whaling since the mid-1960s. Populations of blue whales appear to be recovering and are estimated worldwide at between 10,000 and 25,000 animals. However, the International Union for Conservation of Nature still lists the blue whale as an endangered species.

Additional Information

The blue whale is the largest animal on the planet, weighing as much as 200 tons (approximately 33 elephants). The blue whale has a heart the size of a Volkswagen Beetle. Its stomach can hold one ton of krill and it needs to eat about four tons of krill each day. They are the loudest animals on Earth and are even louder than a jet engine. Their calls reach 188 decibels, while a jet reaches 140 decibels. Their low frequency whistle can be heard for hundreds of miles and is probably used to attract other blue whales.

Whales are at the top of the food chain and have an important role in the overall health of the marine environment. During the 20th century, the blue whale was an important whaling target and even after it was protected and commercial whaling stopped in 1966, exploitation efforts by the former Soviet Union persisted.

Like other large whales, blue whales are threatened by environmental change including habitat loss and toxics. Blue whales can also be harmed by ship strikes and by becoming entangled in fishing gear. Although commercial whaling no longer represents a threat, climate change and its impact on krill (shrimp-like crustaceans), blue whales' major prey, makes this cetacean particularly vulnerable.

Jai Ganesh · Jokes

Q: What's the difference between love and marriage?
A: Love is one long sweet dream, and marriage is the alarm clock.
* * *
Boy: "I love you so much, I could never live without you."
Girl: "Is that you or the beer talking?"
Boy: "It's me talking to the beer."
* * *
What's the definition of a happy marriage?
One where the husband gives and the wife takes.
* * *
Q: What's the difference between love and marriage?
A: Love is blind and marriage is an eye-opener!
* * *
Q: Who is the perfect husband?
A: One who keeps his mouth shut and his checkbook open!
* * *

Jai Ganesh · Dark Discussions at Cafe Infinity

Close Quotes - V

1. We have a close, unshakable bond between the United States and Israel, and between the American and Israeli people. We share common values and a commitment to a democratic future for the world, and we are both committed to a two-state solution. But that doesn't mean that we're going to agree. - Hillary Clinton

2. When I was climbing, I built up a close relationship with the Sherpa people. - Edmund Hillary

3. My inner strength comes from my friends. I have a very close group of friends and family, and we all help each other through our dark times. - Kathy Bates

4. Every country should conduct its own reforms, should develop its own model, taking into account the experience of other countries, whether close neighbours or far away countries. - Mikhail Gorbachev

5. When I'm down or maybe when it's close in the match, I feel like I'm still in it. I don't feel like I'm letting down. Mentally, I'm still really, really tough. - Maria Sharapova

6. Avoid having your ego so close to your position that when your position falls, your ego goes with it. - Colin Powell

7. You can get too close as a team. You need time away from each other. You change in the same dressing room, you play on the same cricket field, you stay in the same hotel, you travel in the same planes and buses. C'mon - this business of everyone holding hands and being pally is nonsense. - Glenn Turner

8. I don't like to leave my children for long periods of time. It's made me more picky about roles that are close, especially on television. - Brooke Shields.

Jai Ganesh · Science HQ

Lead

Gist

Lead is a chemical element with the symbol Pb and atomic number 82. It is a heavy, dense, and soft metal known for being malleable, corrosion-resistant, and having a low melting point. Historically, lead was used in water pipes, leading to the terms "plumbing" and "plumber" from its Latin name, plumbum. While it is a stable element, it is also highly toxic and should be handled and disposed of with care.

Lead and lead compounds have been used in a wide variety of products found in and around our homes, including paint, ceramics, pipes and plumbing materials, solders, gasoline, batteries, ammunition and cosmetics

Summary

Lead is a chemical element with the symbol Pb (from the Latin plumbum) and atomic number 82. It is a heavy metal denser than most common materials. Lead is soft, malleable, and has a relatively low melting point. When freshly cut, it appears shiny gray with a bluish tint, but it tarnishes to dull gray on exposure to air. Lead has the highest atomic number of any 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 shown by its amphoteric behavior: lead and lead oxides react with both acids and bases, and it tends to form covalent bonds. Lead compounds usually occur in the +2 oxidation state rather than the +4 state common in lighter members of the carbon group, with exceptions mostly limited to organolead compounds. Like the lighter members of the group, lead can bond with itself, forming chains and polyhedral structures.

Easily extracted from its ores, lead was known to prehistoric peoples in the Near East. Galena is its principal ore and often contains silver, encouraging its widespread extraction and use in ancient Rome. Production declined after the fall of Rome and did not reach similar levels until the Industrial Revolution. Lead played a role in developing the printing press, as movable type could be readily cast from lead alloys. In 2014, annual global production was about ten million tonnes, over half from recycling. Lead's high density, low melting point, ductility, and resistance to oxidation, together with its abundance and low cost, supported its extensive use in construction, plumbing, batteries, ammunition, weights, solders, pewter, fusible alloys, lead paints, leaded gasoline, and radiation shielding.

Lead is a neurotoxin that accumulates in soft tissues and bones. It damages the nervous system, interferes with biological enzymes, and can cause neurological disorders ranging from behavioral problems to brain damage. It also affects cardiovascular and renal systems. Lead's toxicity was noted by ancient Greek and Roman writers, but became widely recognized in Europe in the late 19th century.

Details

Lead is a chemical element. Its chemical symbol is Pb, which comes from plumbum, the Latin word for lead. Its atomic number is 82, atomic mass is 207.2 and has a melting point of 327.8°C. It is a very poisonous and heavy metal, and is also the ending element to the stable elements, although the next element, bismuth, is so weakly radioactive that it can be considered stable for practical purposes.

Properties:

Physical properties

Lead is a shiny, gray-blue poor metal. It gets tarnished easily to a dull gray color. It is soft and malleable. It is very shiny when it is melted. It is very heavy. It is very corrosion-resistant. It is made stronger by adding antimony or calcium. It can form an alloy with sodium. It is toxic to people and animals when swallowed.

Chemical properties

Lead burns in air with a grayish-white flame, making toxic fumes of lead(II) oxide. Only the surface is corroded by air. It dissolves in nitric acid to make lead(II) nitrate. It does not dissolve in sulfuric or hydrochloric acid. It reacts with sodium nitrate to make lead(II) oxide and sodium nitrite. It reacts with chlorine to make lead(II) chloride. Lead(II) oxide reacts with lead sulfide to make lead metal and sulfur dioxide.

Chemical compounds

Lead makes chemical compounds in two main oxidation states: +2 and +4. +2 compounds, also known as lead(II) compounds or plumbous compounds, are weak oxidizing agents. +4 compounds, also known as lead(IV) compounds or plumbic compounds, are strong oxidizing agents. Lead compounds are toxic just like the element. The lead halides do not dissolve in water. Lead(IV) oxide is the most common lead(IV) compound. It is a black solid. The lead oxides are all colored, while the other salts are white or colorless. Lead nitrate and lead(II) acetate are the soluble compounds of lead.

Mixed oxidation state compounds

Mixed oxidation state compounds contain lead in the +2 and +4 oxidation state.

Occurrence

Lead is found very rarely in the earth's crust as a metal. Normally, lead is in the mineral galena. Galena is lead sulfide. Galena is the main lead ore.

History

Lead was used for thousands of years because it is easy to get from the ground and easy to shape and work with. The Romans used lead very commonly. They used it for pipes, drinking vessels, and fasteners.

Preparation

Lead is made from galena. Galena is made pure by froth flotation to get all the impurities out. Then the lead sulfide is roasted in a furnace to make lead(II) oxide. The lead(II) oxide is heated with coke to make liquid lead metal.

Uses:

As an element

Lead is used in the ballast of sailboats. It is also used in weight belts for scuba diving. It is also used to make shotgun pellets and bullets for small arms. Some printing presses use lead type because it can be easily shaped. It can be used outside because it does not corrode in water.

Lead has been used to make pipes and water ducts, as it is easy to form and cast, and the parts made from lead are easy to fit, and clean water does not corrode lead. The names "plumbing" for waterworks, and "plumber" for a pipe fitter, come from the Latin name of lead, plumbum.

Most lead is used in lead acid batteries, though. The lead is oxidized, making electricity. Sheets of lead are used to block sound in some places. Lead is used in radiation shielding. Molten lead can be used as a coolant in nuclear reactors. It used to be mixed with tin to make the pipes in pipe organs. Different amounts of lead make different sounds. In addition, lead has found its usage in solder.

It is used in some solder. It is used in covering for wires that carry high voltage. Some tennis rackets have lead in them to make them heavier. It is used to balance wheels of cars, to make statues, and to make decorative looks in buildings.

As chemical compounds

Many lead compounds are used to make colored glazes in ceramics. Lead can be used in PVC pipes. Lead compounds are added to candles to make them burn better. Lead glass has lead(II) oxide in it. Lead compounds are still used as pigments in some places. Lead compounds were added to gasoline, but are now outlawed. Some lead compounds are semiconductors and are used in photodetectors.

Old uses

Lead was used in many red, yellow, and white pigments in paints. Lead was also used in pesticides. Lead used to be used in pipes carrying water, but now it is not because lead can leach into the water.

Safety

Although it can be safely touched, exposure to lead should be avoided – it is very toxic to humans and other animals when swallowed, and its use is restricted in many countries.

If someone is exposed to lead for a long time, it ruins their kidneys and gives them abdominal pains. Lead also ruins the nervous system. Lead paint was being eaten by children and they were getting lead poisoning.

The best way to understand lead and its properties is to read its MSDS.

Additional Information

Lead (Pb) is a soft, silvery white or grayish metal in Group 14 (IVa) of the periodic table. Lead is very malleable, ductile, and dense and is a poor conductor of electricity. Known in antiquity and believed by the alchemists to be the oldest of metals, lead is highly durable and resistant to corrosion, as is indicated by the continuing use of lead water pipes installed by the ancient Romans. The symbol Pb for lead is an abbreviation of the Latin word for lead, plumbum.

Element Properties

atomic number : 82
atomic weight : 207.19
melting point : 327.5 °C (621.5 °F)
boiling point : 1,744 °C (3,171.2 °F)
density : 11.29 gram/{cm}^{3} at 20 °C (68 °F)
oxidation states : +2, +4

Occurrence and distribution

Lead is mentioned often in early biblical accounts. The Babylonians used the metal as plates on which to record inscriptions. The Romans used it for tablets, water pipes, coins, and even cooking utensils; indeed, as a result of the last use, lead poisoning was recognized in the time of Augustus Caesar. The compound known as white lead was apparently prepared as a decorative pigment at least as early as 200 bce. Modern developments date to the exploitation in the late 1700s of deposits in the Missouri-Kansas-Oklahoma area in the United States.

On a weight basis, lead has nearly the same abundance in Earth’s crust as tin. Cosmically, there is 0.47 lead atom per 106 silicon atoms. The cosmic abundance is comparable to those of cesium, praseodymium, hafnium, and tungsten, each of which is regarded as a reasonably scarce element.

Although lead is not abundant, natural concentration processes have resulted in substantial deposits of commercial significance, particularly in the United States but also in Canada, Australia, Spain, Germany, Africa, and South America. Significant deposits are found in the United States in the western states and the Mississippi valley. Rarely found free in nature, lead is present in several minerals, but all are of minor significance except the sulfide, PbS (galena, or lead glance), which is the major source of lead production throughout the world. Lead is also found in anglesite (PbSO4) and cerussite (PbCO3). By the early 21st century, China, Australia, the United States, Peru, Mexico, and India were the world’s top producers of lead in concentrate.

Lead may be extracted by roasting the ore and then smelting it in a blast furnace or by direct smelting without roasting. Additional refining removes impurities present in the lead bullion produced by either process. Almost half of all refined lead is recovered from recycled scrap.

Uses of the metal

Only a single crystalline modification, with a close-packed metallic lattice, is known. Properties that are responsible for the many uses of elemental lead include its ductility, ease of welding, low melting point, high density, and ability to absorb gamma radiation and X-radiation. Molten lead is an excellent solvent and collector for elemental silver and gold. The structural applications of lead are limited by its low tensile and fatigue strengths and its tendency to flow even when only lightly loaded.

When freshly cut, lead oxidizes quickly, forming a dull gray coating, formerly thought to be lead suboxide, Pb2O, but now recognized as a mixture of lead and lead monoxide, PbO, which protects the metal from further corrosion. Similarly, although lead is soluble in dilute nitric acid, it is only superficially attacked by hydrochloric or sulfuric acids because the insoluble chloride (PbCl2) or sulfate (PbSO4) coatings that are formed prevent continued reaction. Because of this general chemical resistance, considerable amounts of lead are used in roofing, as coverings for electric cables placed in the ground or underwater, and as linings for water pipes and conduits and structures for the transportation and processing of corrosive substances.

Elemental lead can also be oxidized to the Pb2+ ion by hydrogen ions, but the insolubility of most salts of Pb2+ makes lead resistant to attack by many acids. Oxidation under alkaline conditions is easier to effect and is favoured by the formation of the soluble species of lead in the +2 oxidation state. Lead oxide (PbO2, with lead as the Pb4+ ion) is among the stronger oxidizing agents in acidic solution, but it is comparatively weak in alkaline solution. The ease of oxidation of lead is enhanced by complex formation. The electrodeposition of lead is best effected from aqueous solutions containing lead hexafluorosilicate and hexafluorosilicic acid.

Lead has many other applications, the largest of which is in the manufacture of storage batteries. It is used in ammunition (shot and bullets) and as a constituent of solder, type metal, bearing alloys, fusible alloys, and pewter. In heavy and industrial machinery, sheets and other parts made from lead compounds may be used to dampen noise and vibration. Because lead effectively absorbs electromagnetic radiation of short wavelengths, it is used as a protective shielding around nuclear reactors, particle accelerators, X-ray equipment, and containers used for transporting and storing radioactive materials. Together with the compound lead oxide (PbO2) and with lead-antimony or lead-calcium alloys, it is employed in common storage batteries.

Properties of the element

Lead and its compounds are toxic and are retained by the body, accumulating over a long period of time—a phenomenon known as cumulative poisoning—until a lethal quantity is reached. The toxicity of lead compounds increases as their solubility increases. In children the accumulation of lead may result in cognitive deficits; in adults it may produce progressive renal disease. Symptoms of lead poisoning include abdominal pain and diarrhea followed by constipation, nausea, vomiting, dizziness, headache, and general weakness. Elimination of contact with a lead source is normally sufficient to effect a cure. The elimination of lead from insecticides and paint pigments and the use of respirators and other protective devices in areas of exposure have reduced lead poisoning materially. The recognition that the use of tetraethyl lead, Pb(C2H5)4, as an antiknock additive in gasoline was polluting the air and water led to the compound’s elimination as a gasoline constituent in the 1980s. (For full treatment of lead and lead mining and refining, see also lead poisoning.)

Nuclear properties

Lead is formed both by neutron-absorption processes and the decay of radionuclides of heavier elements. Lead has four stable isotopes; their relative abundances are lead-204, 1.48 percent; lead-206, 23.6 percent; lead-207, 22.6 percent; and lead-208, 52.3 percent. Three stable lead nuclides are the end products of radioactive decay in the three natural decay series: uranium (decays to lead-206), thorium (decays to lead-208), and actinium (decays to lead-207). More than 30 radioactive isotopes have been reported. Of the radioactive isotopes of lead, the following appear as members of the three natural decay series: (1) thorium series: lead-212; (2) uranium series: lead-214 and lead-210; (3) actinium series: lead-211. The atomic weight of natural lead varies from source to source, depending on its origin by heavier element decay.

Compounds

Lead shows oxidation states of +2 and +4 in its compounds. Among the many important lead compounds are the oxides: lead monoxide, PbO, in which lead is in the +2 state; lead dioxide, PbO2, in which lead is in the +4 state; and trilead tetroxide, Pb3O4. Lead monoxide exists in two modifications, litharge and massicot. Litharge, or alpha lead monoxide, is a red or reddish yellow solid, has a tetragonal crystal structure, and is the stable form at temperatures below 488 °C (910 °F). Massicot, or beta lead monoxide, is a yellow solid and has an orthorhombic crystal structure; it is the stable form above 488 °C. Both forms are insoluble in water but dissolve in acids to form salts containing the Pb2+ ion or in alkalies to form plumbites, which have the PbO22− ion. Litharge, which is produced by air oxidation of lead, is the most important commercial compound of lead; it is used in large amounts directly and as the starting material for the preparation of other lead compounds. Considerable quantities of PbO are consumed in manufacturing the plates of lead-acid storage batteries. High-quality glassware (lead crystal) contains as much as 30 percent litharge, which increases the refractive index of the glass and makes it brilliant, strong, and resonant. Litharge is also employed as a drier in varnishes and in making sodium plumbite, which is used for removing malodorous thiols (a family of organic compounds containing sulfur) from gasoline.

PbO2, found in nature as the brown-to-black mineral plattnerite, is commercially produced from trilead tetroxide by oxidation with chlorine. It decomposes upon heating and yields oxygen and lower oxides of lead. PbO2 is used as an oxidizing agent in the production of dyestuffs, chemicals, pyrotechnics, and matches and as a curing agent for polysulfide rubbers. Trilead tetroxide (known as red lead, or minium) is produced by further oxidation of PbO. It is the orange-red to brick-red pigment commonly used in corrosion-resistant paints for exposed iron and steel. It also reacts with ferric oxide to form a ferrite used in making permanent magnets.

Another economically significant compound of lead in the +2 oxidation state is lead acetate, Pb(C2H3O2)2, a water-soluble salt made by dissolving litharge in concentrated acetic acid. The common form, the trihydrate, Pb(C2H3O2)2·3H2O, called sugar of lead, is used as a mordant in dyeing and as a drier in certain paints. In addition, it is utilized in the production of other lead compounds and in gold cyanidation plants, where it primarily serves to precipitate soluble sulfides from solution as PbS.

Various other salts, most notably basic lead carbonate, basic lead sulfate, and basic lead silicate, were once widely employed as pigments for white exterior paints. Since the mid-20th century, however, the use of such so-called white lead pigments has decreased substantially because of a concern over their toxicity and attendant hazard to human health. The use of lead math in insecticides has virtually been eliminated for the same reason.

More Information:

Appearance

A dull, silvery-grey metal. It is soft and easily worked into sheets.

Uses

This easily worked and corrosion-resistant metal has been used for pipes, pewter and paint since Roman times. It has also been used in lead glazes for pottery and, in this century, insecticides, hair dyes and as an anti-knocking additive for petrol. All these uses have now been banned, replaced or discouraged as lead is known to be detrimental to health, particularly that of children.

Lead is still widely used for car batteries, pigments, ammunition, cable sheathing, weights for lifting, weight belts for diving, lead crystal glass, radiation protection and in some solders.

It is often used to store corrosive liquids. It is also sometimes used in architecture, for roofing and in stained glass windows.

Biological role

Lead has no known biological role. It can accumulate in the body and cause serious health problems. It is toxic, teratogenic (disturbs the development of an embryo or foetus) and carcinogenic.

Daily intake of lead from all sources is about 0.1 milligrams. The average human body stores about 120 milligrams of lead in the bones.

Natural abundance

Lead is chiefly obtained from the mineral galena by a roasting process. At least 40% of lead in the UK is recycled from secondary sources such as scrap batteries and pipes.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#10553. What does the term in Geography Border mean?

#10554. What does the term in Geography Bornhardt mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#5747. What does the noun matador mean?

#5748. What does the noun matchwood mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#2467. What does the medical term Doppler ultrasonography mean?

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#9733.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6240.

Jai Ganesh · Exercises

Hi,

2583.

Jai Ganesh · Dark Discussions at Cafe Infinity

2335) Demis Hassabis

Gist

Work:

Proteins control and drive all the chemical reactions that together are the basis of life. Proteins generally consist of 20 different amino acids. These are linked together in long strings that fold up to make a three-dimensional structure. In 2020, Demis Hassabis and John Jumper presented an AI model called AlphaFold2. With its help, they have been able to predict the structure of virtually all known proteins. AlphaFold2 has been widely used in many areas, including research into pharmaceuticals and environmental technology.

Summary

Demis Hassabis (born July 27, 1976, London, England) is an English computer scientist who was awarded the 2024 Nobel Prize in Chemistry for his work using artificial intelligence (AI) to predict protein structures. He shared half the prize with his colleague, American computer scientist John M. Jumper, and the other half of the prize was awarded to American biochemist David Baker.

Early life and career

Hassabis spent his early life in north London. The eldest son of a Greek Cypriot father and a Chinese Singaporean mother, Hassabis developed a keen interest in chess and computer programming. A chess player from age four, Hassabis obtained the rank of chess master at age 13. His affection for computer games inspired him to code his first game, a version of Othello, and teach himself computer programming from books.

Hassabis would go on to write code for the games company Bullfrog Productions, where by age 17 he served as the lead developer of the AI-generated video game Theme Park (1994). During this period he attended grammar school at Queen Elizabeth’s School and secondary school at Christ’s College, Finchley. At Finchley he completed his examinations at age 16, two years early.

During the 1990s Hassabis studied computer science at the University of Cambridge, where he captained the college’s chess team. After graduating from Cambridge in 1997, Hassabis became the lead AI programmer at Lionhead Studios, where he assisted in the development of the game Black & White (2001). He left Lionhead Studios in 1998 to found Elixir Studios, where he went on to produce a number of award-winning AI-based video games, including Republic: The Revolution (2003) and Evil Genius (2004).

After selling his holdings in Elixir Studios in 2005, Hassabis took his passion for AI algorithms in a different direction. He pursued a Ph.D. in cognitive neuroscience at the University College London (UCL), in large part to understand how the human brain managed imagination and memory. After graduating from UCL in 2009, Hassabis did his postdoctoral work at Harvard University and the Massachusetts Institute of Technology (MIT) and became a Henry Wellcome fellow at UCL.

DeepMind

Hassabis founded DeepMind, an AI-based start-up company, along with New Zealand computer scientist Shane Legg and English entrepreneur Mustafa Suleyman in 2011. Over the next four years he developed a series of AI models and trained them using deep learning to play and master video games without teaching the AI the rules. Hassabis and his colleagues sold DeepMind to Google in 2014, with Hassabis remaining to serve as CEO.

The DeepMind AI became the platform for AlphaGo, which would defeat top go player Lee Sedol four games to one in 2016. AlphaGo’s neural networks had learned to play go from human players and by playing itself. AlphaGo was in turn surpassed by AlphaGo Zero, which, starting from only the rules of go, shut out AlphaGo 100 games to 0. A more general neural network, Alpha Zero, used the same techniques to quickly master chess and shogi.

AI solves protein folding

Despite the media interest generated by the victories of DeepMind’s game-playing AIs, Hassabis was actually interested in applying what he learned from those AI successes to scientific problems, specifically that of protein folding. Proteins are large molecules that are directly involved in the chemical processes essential for life and are built up from 20 amino acids that can be combined in many different ways. The function of a protein is determined by its three-dimensional structure, which can be quite complex, based on how the string of amino acids is folded.

How a protein is folded is determined by its amino acid sequence. However, even a small protein of only 100 amino acids can have 1047 possible three-dimensional structures. Predicting a protein’s structure from its amino acid sequence became a key problem in molecular biology.

In 1994 biologists John Moult and Krzysztof Fidelis founded the Critical Assessment of protein Structure Prediction (CASP) challenge to test methods for predicting protein structures. Every two years, contestants were given the amino acid sequences for proteins whose structure had been determined but not published and were challenged to predict the protein structures.

Progress was slow. By the mid-2010s the best models in the CASP challenge were about 40 percent accurate. DeepMind entered its protein structure program AlphaFold in CASP13 in 2018 and delivered an astonishing accuracy of about 60 percent, far ahead of any competitors. However, improvement beyond that was difficult, until Jumper joined DeepMind and used his experience with protein simulation to help develop AlphaFold2.

AlphaFold2 was trained on databases of amino acid sequences and protein structures and used a neural network called a transformer to find a likely protein structure. At CASP14 in 2020, AlphaFold2 reached an accuracy of 90 percent, which is comparable with experimental results. The problem of finding a protein structure given an amino acid sequence had been solved.

Hassabis, Jumper, and their collaborators used AlphaFold2 to calculate the structure of almost all of the more than 50,000 human proteins in 2021. They then went even further and calculated the structures of almost all of the 200 million known proteins, which come from about 1 million different species, or as Hassabis called it, “the entire protein universe.”

Hassabis has garnered a number of accolades, including the Royal Society’s Mullard Award (2014), the Pius XI Medal from the Pontifical Academy of Sciences (2020), and the Wiley Prize in Biomedical Sciences (2022). In 2023 he was awarded the Breakthrough Prize in Life Sciences, the Canada Gairdner International Award, and the Albert Lasker Basic Medical Research Award.

Details

Sir Demis Hassabis (born 27 July 1976) is a British artificial intelligence (AI) researcher and entrepreneur. He is the chief executive officer and co-founder of Google DeepMind and Isomorphic Labs, and a UK Government AI Adviser. In 2024, Hassabis and John M. Jumper were jointly awarded the Nobel Prize in Chemistry for their AI research contributions for protein structure prediction.

Hassabis is a Fellow of the Royal Society and has won many prestigious awards for his research efforts, including the Breakthrough Prize, the Canada Gairdner International Award and the Lasker Award. In 2017 he was appointed a CBE and was included in the Time 100, a list of the most influential people in the world. In 2024 Hassabis was knighted for his work on AI. He was listed in the Time 100 again in 2025, this time featured in one of the five covers of the printed version.

Early life and education

Hassabis was born to Costas and Angela Hassabis. His father is Greek Cypriot and his mother is from Singapore. Demis grew up in North London. In his early career he was a video game AI programmer and designer and an expert board games player. A child prodigy in chess from the age of four, Hassabis reached master standard at the age of 13 with an Elo rating of 2300 (at the time the second-highest rated player in the world for his age group after Judit Polgar) and captained many of the England junior chess teams. He represented the University of Cambridge in the Oxford–Cambridge varsity chess matches of 1995, 1996 and 1997, winning a half blue.

He first got interested in technology after buying his first computer in 1984, a ZX Spectrum 48K, funded from chess winnings. He taught himself how to program from books. He subsequently wrote his first AI program on a Commodore Amiga to play the reversi board game.

Between 1988 and 1990 Hassabis was educated at Queen Elizabeth's School, Barnet, a boys' grammar school in North London. He was subsequently home-schooled by his parents for a year, before studying at the comprehensive school Christ's College, Finchley. He completed his A-level exams a year early at 16.

Bullfrog Productions

Asked by Cambridge University to take a gap year owing to his young age, Hassabis began his computer games career at Bullfrog Productions after entering an Amiga Power "Win-a-job-at-Bullfrog" competition. He began by level designing on Syndicate and then at 17 co-designing and lead-programming on the 1994 game Theme Park, with the game's designer Peter Molyneux. Theme Park, a simulation video game, sold several million copies and inspired a whole genre of simulation sandbox games. He earned enough from his gap year to pay his own way through university.

University of Cambridge

Hassabis left Bullfrog to study at Queens' College, Cambridge, where he completed the Computer Science Tripos and graduated in 1997 with a double first.

Career and research:

Lionhead

After graduating from Cambridge, Hassabis worked at Lionhead Studios. Games designer Peter Molyneux, with whom Hassabis had worked at Bullfrog Productions, had recently founded the company. At Lionhead, Hassabis worked as lead AI programmer on the 2001 god game Black & White.

Elixir Studios

Hassabis left Lionhead in 1998 to found Elixir Studios, a London-based independent games developer, signing publishing deals with Eidos Interactive, Vivendi Universal and Microsoft. In addition to managing the company, Hassabis served as executive designer of the games Republic: The Revolution and Evil Genius. Each received BAFTA nominations for their interactive music scores, created by James Hannigan.

The release of Elixir's first game, Republic: The Revolution, a highly ambitious and unusual political simulation game, was delayed due to its huge scope, which involved an AI simulation of the workings of an entire fictional country. The final game was reduced from its original vision and greeted with lukewarm reviews, receiving a Metacritic score of 62/100. Evil Genius, a tongue-in-cheek Austin Powers parody, fared much better with a score of 75/100. In April 2005 the intellectual property and technology rights were sold to various publishers and the studio was closed.

Neuroscience research

Following Elixir Studios, Hassabis returned to academia to obtain his PhD in cognitive neuroscience from UCL Queen Square Institute of Neurology in 2009 supervised by Eleanor Maguire. He sought to find inspiration in the human brain for new AI algorithms.

He continued his neuroscience and artificial intelligence research as a visiting scientist jointly at Massachusetts Institute of Technology (MIT), in the lab of Tomaso Poggio, and Harvard University, before earning a Henry Wellcome postdoctoral research fellowship to the Gatsby Computational Neuroscience Unit at UCL in 2009 working with Peter Dayan.

Working in the field of imagination, memory, and amnesia, he co-authored several influential papers published in Nature, Science, Neuron, and PNAS. His very first academic work, published in PNAS, was a landmark paper that showed systematically for the first time that patients with damage to their hippocampus, known to cause amnesia, were also unable to imagine themselves in new experiences. The finding established a link between the constructive process of imagination and the reconstructive process of episodic memory recall. Based on this work and a follow-up functional magnetic resonance imaging (fMRI) study, Hassabis developed a new theoretical account of the episodic memory system identifying scene construction, the generation and online maintenance of a complex and coherent scene, as a key process underlying both memory recall and imagination. This work received widespread coverage in the mainstream media and was listed in the top 10 scientific breakthroughs of the year by the journal Science. He later generalised these ideas to advance the notion of a 'simulation engine of the mind' whose role it was to imagine events and scenarios to aid with better planning.

DeepMind

Hassabis is the CEO and co-founder of DeepMind, a machine learning AI startup, founded in London in 2010 with Shane Legg and Mustafa Suleyman. Hassabis met Legg when both were postdocs at the Gatsby Computational Neuroscience Unit, and he and Suleyman had been friends through family. Hassabis also recruited his university friend and Elixir partner David Silver.

DeepMind's mission is to "solve intelligence" and then use intelligence "to solve everything else". More concretely, DeepMind aims to combine insights from systems neuroscience with new developments in machine learning and computing hardware to unlock increasingly powerful general-purpose learning algorithms that will work towards the creation of an artificial general intelligence (AGI). The company has focused on training learning algorithms to master games, and in December 2013 it announced that it had made a pioneering breakthrough by training an algorithm called a Deep Q-Network (DQN) to play Atari games at a superhuman level by using only the raw pixels on the screen as inputs.

DeepMind's early investors included several high-profile tech entrepreneurs. In 2014, Google purchased DeepMind for £400 million. Although most of the company has remained an independent entity based in London, DeepMind Health has since been directly incorporated into Google Health.

Since the Google acquisition, the company has notched up a number of significant achievements, perhaps the most notable being the creation of AlphaGo, a program that defeated world champion Lee Sedol at the complex game of Go. Go had been considered a holy grail of AI, for its high number of possible board positions and resistance to existing programming techniques. However, AlphaGo beat European champion Fan Hui 5–0 in October 2015 before winning 4–1 against former world champion Lee Sedol in March 2016 and winning 3–0 against the world's top-ranked player Ke Jie in 2017. Additional DeepMind accomplishments include creating a neural Turing machine, reducing the energy used by the cooling systems in Google's data centers by 40%, advancing research on AI safety, and the creation of a partnership with the National Health Service (NHS) of the United Kingdom and Moorfields Eye Hospital to improve medical services and identify the onset of degenerative eye conditions.

DeepMind has also been responsible for technical advances in machine learning, having produced a number of award-winning papers. In particular, the company has made significant advances in deep learning and reinforcement learning, and pioneered the field of deep reinforcement learning which combines these two methods. Hassabis has predicted that artificial intelligence will be "one of the most beneficial technologies of mankind ever" but that significant ethical issues remain.

Hassabis has also warned of the potential dangers and risks of AI if misused, and has been a strong advocate of further AI safety research being needed. In 2023, he signed the statement that "Mitigating the risk of extinction from AI should be a global priority alongside other societal-scale risks such as pandemics and nuclear war". He considers however that a pause on AI progress would be very hard to enforce worldwide, and that the potential benefits (e.g. for health and against climate change) make it worth continuing. He said that there is an urgent need for research on evaluation tests that measure how capable and controllable new AI models are.

AlphaFold

In 2016, DeepMind turned its artificial intelligence to protein structure prediction, a 50-year grand challenge in science, to predict the 3D structure of a protein from its 1D amino acid sequence. This is an important problem in biology, as proteins are essential to life, almost every biological function depends on them, and the function of a protein is thought to be related to its structure. Knowing the structure of a protein can be very helpful in drug discovery and disease understanding. In December 2018, DeepMind's tool AlphaFold won the 13th Critical Assessment of Techniques for Protein Structure Prediction (CASP) by successfully predicting the most accurate structure for 25 out of 43 proteins. "This is a lighthouse project, our first major investment in terms of people and resources into a fundamental, very important, real-world scientific problem", Hassabis said to The Guardian.

In November 2020, DeepMind again announced world-beating results in the CASP14 edition of the competition with AlphaFold 2, a new version of the system. It achieved a median global distance test (GDT) score of 87.0 across protein targets in the challenging free-modeling category, much higher than the same 2018 results with a median GDT < 60, and an overall error of less than the width of an atom (<1 Angstrom), making it competitive with experimental methods, and leading the organisers of CASP to declare the problem essentially solved. Over the next year DeepMind used AlphaFold2 to fold all 200 million proteins known to science, and made the system and these structures openly and freely available for anyone to use via the AlphaFold Protein Structure Database developed in collaboration with EMBL-EBI.

Personal life

Hassabis resides in North London with his family. He is also a lifelong fan of Liverpool FC. Hassabis is the main subject of the documentary called The Thinking Game, which premiered at the 2024's Tribeca Festival, from the same filmmaker as the award-winning documentary AlphaGo (2017) which chronicles the famous 2016 $1M challenge match in Seoul, South Korea, between Lee Sedol and AlphaGo.

Jai Ganesh · Jai Ganesh's Puzzles

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#10551. What does the term in Geography Body of water mean?

#10552. What does the term in Geography Bog mean?

Jai Ganesh · Jai Ganesh's Puzzles

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#5745. What does the adjective gregarious mean?

#5746. What does the noun gremlin mean?

Jai Ganesh · This is Cool

Glucose

Gist

Glucose is a simple sugar (a monosaccharide) with the chemical formula C₆H₁₂O₆ that serves as the body's primary energy source. Your body derives glucose from the food you eat, and it is transported through the bloodstream to cells, where hormones like insulin help regulate its uptake for energy production (ATP) and storage as glycogen. Plants produce glucose through photosynthesis, and it is central to the metabolism of all living organisms, fueling virtually all energy-requiring processes.

Glucose is a simple sugar and the main type of carbohydrate that serves as the primary source of energy for the body's cells, fueling functions from muscle contraction to nerve impulse conduction. It is carried in the bloodstream as blood sugar or blood glucose and enters cells with the help of the hormone insulin. Your body obtains glucose from the foods you eat, particularly carbohydrates like fruits, bread, and pasta, which are broken down into this fundamental fuel, or it can produce glucose from other substances through processes like gluconeogenesis.

Summary

Glucose is a sugar with the molecular formula C6H12O6. It is the most abundant monosaccharide, a subcategory of carbohydrates. It is made from water and carbon dioxide during photosynthesis by plants and most algae. It is used by plants to make cellulose, the most abundant carbohydrate in the world, for use in cell walls, and by all living organisms to make adenosine triphosphate (ATP), which is used by the cell as energy. Glucose is often abbreviated as Glc.

In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as amylose and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form is d-glucose, while its stereoisomer l-glucose is produced synthetically in comparatively small amounts and is less biologically active. Glucose is a monosaccharide containing six carbon atoms and an aldehyde group, and is therefore an aldohexose. The glucose molecule can exist in an open-chain (acyclic) as well as ring (cyclic) form. Glucose is naturally occurring and is found in its free state in fruits and other parts of plants. In animals, it is released from the breakdown of glycogen in a process known as glycogenolysis.

Glucose, as intravenous sugar solution, is on the World Health Organization's List of Essential Medicines. It is also on the list in combination with sodium chloride (table salt).

Details

Dietary glucose is a monosaccharide (simple sugar), making it the simplest type of carbohydrate (carb).

When you consume dietary glucose, your body converts it into blood glucose. This is one of your body’s primary fuel sources, along with fat and protein.

According to the American Heart Association, the body digests complex carbs more slowly than simple carbs, making them a healthier and steadier energy source.

If you’re living with diabetes, perhaps more important is that complex carbs release glucose into the bloodstream gradually rather than immediately. This makes them less likely to cause blood glucose spikes.

Unmanaged glucose levels may have permanent and severe effects.

How does the body process glucose?

Your body ideally uses glucose multiple times per day.

When you eat, your body quickly starts processing glucose and other carbohydrates. Then, enzymes begin to break them down with help from the pancreas.

The pancreas plays a key roleTrusted Source in the way your body metabolizes glucose.

When blood glucose levels increase, the pancreas releases a hormone called insulin. This manages the rising blood sugar level by getting glucose into your cells.

Then, muscle, fat, and other cells use glucose for energy or store it as fat for later use.

If your pancreas doesn’t produce insulin the way it should, you may develop diabetes. In this case, you may need medical treatment to help process and regulate glucose in the body.

Insulin resistance

A 2018 review suggests that diabetes may also occur from insulin resistance. This is when the body’s cells do not sense insulin, and too much sugar remains in the bloodstream.

When the body doesn’t respond to insulin the way it should, it stops glucose from entering your cells and being used for energy. Your cells respond by signaling the creation of ketones, which occurs at night and during fasting or dieting.

Over time, insulin resistance may lead to low insulin levels, according to the American Diabetes Association (ADA). Your body may also release fat from fat cells, and the liver will keep releasing ketones, lowering your blood pH to an acidic level.

This typically occurs in type 1 diabetes, where there’s little to no insulin production.

In type 2 diabetes, insulin levels do eventually decrease, but typically not to a level that raises ketones high enough to cause the blood to be acidic.

When your body cannot use glucose properly, the buildup of ketones and changes in blood pH may lead to ketoacidosis. This is a severe, life threatening complication of diabetes that requires immediate medical treatment.

Ketogenic diet and diabetes

The keto diet has gained popularity, but it’s a medical diet with risks.

According to a 2019 study, a low carb or keto diet may reduce body weight, but people with diabetes and taking certain medications may have an increased risk of developing ketoacidosis.

Everyone may experience other adverse effects, such as high cholesterol, which is associated with cardiovascular disease.

It’s best to speak with your doctor before starting any diet plan to help prevent complications.

How do you test your glucose?

Monitoring glucose levels is important for people with diabetes.

A simple blood test called a blood glucose meter is one of the most common ways to test glucose at home when living with diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Trusted Source.

Here’s how to use a blood glucose meter:

* Using a small lancet needle, prick the side of your fingertip to produce a drop of blood.
* Apply the blood to a testing strip.
* Place the strip into a meter.
* The meter shows how much glucose is in your blood at that moment.
* Working with a doctor to help set your glucose goals is important, as these depend on factors like your condition, age, and health history.

How often should you check your blood sugar levels?

Your needs, goals, and treatment plan may dictate how often and when to check your blood sugar level.

To stay on top of your glucose levels, speak with a doctor about when and how frequently you should check your levels. They may suggest checking your levels at the following times:

* before and after meals
* before and after exercise
* during long or intense exercise
* before bedtime
* when starting new medications or a new insulin schedule
* when starting a new work schedule
* when traveling across time zones

Continuous glucose monitor

When managing diabetes, you may consider using a continuous glucose monitoring (CGM) system. The device automatically tracks your glucose 24 hours per day and alerts you when it gets too high or low.

According to the NIDDK, the benefits of a CGM include:

* needing fewer finger pricks
* helping better manage glucose
* leading to fewer emergencies.

Additional Information

Glucose is a one of a group of carbohydrates known as simple sugars (monosaccharides). Glucose (from Greek glykys; “sweet”) has the molecular formula C6H12O6. It is found in fruits and honey and is the major free sugar circulating in the blood of higher animals.

Glucose is the source of energy in cell function. The regulation of its metabolism is of great importance and is relevant in various metabolic processes, examples being fermentation and gluconeogenesis. Molecules of starch, the major energy-reserve carbohydrate of plants, consist of thousands of linear glucose units. Another major compound composed of glucose is cellulose, which is also linear. Dextrose is the molecule d-glucose.

The maintenance of the glucose content of vertebrate blood requires glucose 6-phosphate to be converted to glucose. This process occurs in the kidney, in the lining of the intestine, and most importantly in the liver. The liver stores excess glucose as glycogen, a reserve carbohydrate, and releases it when blood glucose levels drop, thereby preventing hypoglycemia. In addition, the liver can produce glucose from non-carbohydrate sources through gluconeogenesis, which helps ensure a steady supply of glucose for the body.

glucose-molecule-carlos-clarivanscience-photo-library.jpg

Jai Ganesh · Jai Ganesh's Puzzles

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#2466. What does the medical term Brachiocephalic artery mean?

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#9732.

Jai Ganesh · Jai Ganesh's Puzzles

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#6239.

Jai Ganesh · Exercises

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2582.

Jai Ganesh · Science HQ

Thallium

Gist

Thallium (Tl) is a highly toxic, silvery-white post-transition metal, atomic number 81, found in trace amounts in the Earth's crust and sulfide ores. Although once used in rodenticides and some medical applications, its use has been largely banned due to severe poisoning risks, mimicking symptoms of other diseases, and potential for criminal misuse. Thallium poisoning can be treated with Prussian Blue, and the element is still used in some specialized electronic and optical applications.

Thallium blood concentration levels are normal below 2 µg/L, and toxic at concentrations greater than 200 µg/L. Long-term effects of thallium exposure can include difficulty walking, various involuntary movement disorders, and impairment of thought and mood. Neurological damage resolves slowly and may be permanent.

Summary

Thallium is a chemical element; it has symbol Tl and atomic number 81. It is a silvery-white post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently, in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek thallós, meaning "green shoot" or "twig", was named by Crookes. It was isolated by both Lamy and Crookes in 1862, Lamy by electrolysis and Crookes by precipitation and melting of the resultant powder. Crookes exhibited it as a powder precipitated by zinc at the International Exhibition, which opened on 1 May that year.

Thallium tends to form the +3 and +1 oxidation states. The +3 state resembles that of the other elements in group 13 (boron, aluminium, gallium, indium). However, the +1 state, which is far more prominent in thallium than the elements above it, recalls the chemistry of alkali metals and thallium(I) ions are found geologically mostly in potassium-based ores and (when ingested) are handled in many ways like potassium ions (K+) by ion pumps in living cells.

Commercially, thallium is produced not from potassium ores, but as a byproduct from refining of heavy-metal sulfide ores. Approximately 65% of thallium production is used in the electronics industry and the remainder is used in the pharmaceutical industry and in glass manufacturing. It is also used in infrared detectors. The radioisotope thallium-201 (as the soluble chloride TlCl) is used in small amounts as an agent in a nuclear medicine scan, during one type of nuclear cardiac stress test.

Soluble thallium salts (many of which are nearly tasteless) are highly toxic and they were historically used in rat poisons and insecticides. Because of their nonselective toxicity, use of these compounds has been restricted or banned in many countries. Thallium poisoning usually results in hair loss.

Details

Thallium (Tl) is a chemical element, metal of main Group 13 (IIIa, or boron group) of the periodic table, poisonous and of limited commercial value. Like lead, thallium is a soft, low-melting element of low tensile strength. Freshly cut thallium has a metallic lustre that dulls to bluish gray upon exposure to air. The metal continues to oxidize upon prolonged contact with air, generating a heavy nonprotective oxide crust. Thallium dissolves slowly in hydrochloric acid and dilute sulfuric acid and rapidly in nitric acid.

Rarer than tin, thallium is concentrated in only a few minerals that have no commercial value. Trace amounts of thallium are present in sulfide ores of zinc and lead; in the roasting of these ores, the thallium becomes concentrated in the flue dusts, from which it is recovered.

British chemist Sir William Crookes discovered (1861) thallium by observing the prominent green spectral line generated by selenium-bearing pyrites that had been used in the manufacture of sulfuric acid. Crookes and French chemist Claude-Auguste Lamy independently isolated (1862) thallium, showing it to be a metal.

Two crystalline forms of the element are known: close-packed hexagonal below about 230 °C (450 °F) and body-centred cubic above. Natural thallium, the heaviest of the boron group elements, consists almost entirely of a mixture of two stable isotopes: thallium-203 (29.5 percent) and thallium-205 (70.5 percent). Traces of several short-lived isotopes occur as decay products in the three natural radioactive disintegration series: thallium-206 and thallium-210 (uranium series), thallium-208 (thorium series), and thallium-207 (actinium series).

Thallium metal has no commercial use, and thallium compounds have no major commercial application, since thallous sulfate was largely replaced in the 1960s as a rodenticide and insecticide. Thallous compounds have a few limited uses. For example, mixed bromide-iodide crystals (TlBr and TlI) that transmit infrared light have been fabricated into lenses, windows, and prisms for infrared optical systems. The sulfide (Tl2S) has been employed as the essential component in a highly sensitive photoelectric cell and the oxysulfide in an infrared-sensitive photocell (thallofide cell). Thallium forms its oxides in two different oxidation states, +1 (Tl2O) and +3 (Tl2O3). Tl2O has been used as an ingredient in highly refractive optical glasses and as a colouring agent in artificial gems; Tl2O3 is an n-type semiconductor. Alkali halide crystals, such as sodium iodide, have been doped or activated by thallium compounds to produce inorganic phosphors for use in scintillation counters to detect radiation.

Thallium imparts a brilliant green coloration to a bunsen flame. Thallous chromate, formula Tl2CrO4, is best used in the quantitative analysis of thallium, after any thallic ion, Tl3+, present in the sample has been reduced to the thallous state, Tl+.

Thallium is typical of the Group 13 elements in having an s2p1 outer electron configuration. Promoting an electron from an s to a p orbital allows the element to be three or four covalent. With thallium, however, the energy required for s → p promotion is high relative to the Tl–X covalent bond energy that is regained on formation of TlX3; hence, a derivative with a +3 oxidation state is not a very energetically favoured reaction product. Thus, thallium, unlike the other boron group elements, predominantly forms singly charged thallium salts having thallium in the +1 rather than the +3 oxidation state (the 6s2 electrons remain unused). It is the only element to form a stable singly charged cation with the outer electron configuration (n-1)d10ns2, which is, unusually enough, not an inert gas configuration. In water the colourless, more stable thallous ion, Tl+, resembles the heavier alkali metal ions and silver; the compounds of thallium in its +3 state are easily reduced to compounds of the metal in its +1 state.

In its oxidation state of +3, thallium resembles aluminum, although the ion Tl3+ appears to be too large to form alums. The very close similarity in size of the singly charged thallium ion, Tl+, and the rubidium ion, Rb+, makes many Tl+ salts, such as the chromate, sulfate, nitrate, and halides, isomorphous (i.e., have an identical crystal structure) to the corresponding rubidium salts; also, the ion Tl+ is able to replace the ion Rb+ in the alums. Thus, thallium does form an alum, but in doing so it replaces the M+ ion, rather than the expected metal atom M3+, in M+M3+(SO4)2∙12H2O.

Soluble thallium compounds are toxic. The metal itself is changed to such compounds by contact with moist air or skin. Thallium poisoning, which may be fatal, causes nervous and gastrointestinal disorders and rapid loss of hair.

Element Properties
atomic number : 81
atomic weight : 204.37
melting point : 303.5 °C (578.3 °F)
boiling point : 1,457 °C (2,655 °F)
specific gravity : 11.85 (at 20 °C [68 °F])
oxidation states : +1, +3.

Additional Information:

Appearance

A soft, silvery-white metal that tarnishes easily.

Uses

The use of thallium is limited as it is a toxic element. Thallium sulfate was employed as a rodent killer – it is odourless and tasteless – but household use of this poison has been prohibited in most developed countries.

Most thallium is used by the electronics industry in photoelectric cells. Thallium oxide is used to produce special glass with a high index of refraction, and also low melting glass that becomes fluid at about 125K.

An alloy of mercury containing 8% thallium has a melting point 20°C lower than mercury alone. This can be used in low temperature thermometers and switches.

Biological role

Thallium has no known biological role. It is very toxic and there is evidence that the vapour is both teratogenic (disturbs the development of an embryo or foetus) and carcinogenic. It can displace potassium around the body affecting the central nervous system.

Natural abundance

Thallium is found in several ores. One of these is pyrites, which is used to produce sulfuric acid. Some thallium is obtained from pyrites, but it is mainly obtained as a by-product of copper, zinc and lead refining.

Thallium is also present in manganese nodules found on the ocean floor.

Jai Ganesh · Dark Discussions at Cafe Infinity

Close Quotes - IV

1. Members of India's diaspora, living in distant lands of the world, my good wishes to all of you. You may be far away from India, but you are always close to our hearts. - Atal Bihari Vajpayee

2. Thankfully, I have my mom and a small group of close friends who are there for me 24/7 and whom I can trust and depend on. - Christina Aguilera

3. China and India are close neighbours linked by mountains and rivers and the Chinese and Indian peoples have enjoyed friendly exchanges for thousands of years. - Li Peng

4. Every country should conduct its own reforms, should develop its own model, taking into account the experience of other countries, whether close neighbours or far away countries. - Mikhail Gorbachev

5. My inner strength comes from my friends. I have a very close group of friends and family, and we all help each other through our dark times. - Kathy Bates

6. Viggo Mortensen had the biggest impact on me in terms of approach, dedication, intention, and artistic outlook, and I'm nowhere close to how good he is as an artist, and I wouldn't even put myself in the same category as an actor. - Orlando Bloom

7. Avoid having your ego so close to your position that when your position falls, your ego goes with it. - Colin Powell

8. We are not even close to finishing the basic dream of what the PC can be. - Bill Gates.

Jai Ganesh · Jokes

Q: Did you know that even big tough guys read?
A: Yeah, just ask Conan the Librarian.
* * *
Q: Did you hear about the librarian who couldn't understand sarcasm?
A: Apparently, she couldn't read between the lines.
* * *
Q: Have you read the book Raising Dogs? No?
A: You should, it's a pup-up book.
* * *
Q: Did you hear about the power outage at the Arizona State University library?
A: Thirty students were stuck on the escalator for three hours.
* * *
Q: What do you get when you cross a librarian and a lawyer?
A: All the information in the world, but you can't understand a word of it.
* * *

Jai Ganesh · This is Cool

2386) Bat (Mammal)

Gist

Mammals are a group of vertebrate animals. Examples of mammals include rats, cats, dogs, deer, monkeys, apes, bats, whales, dolphins, and humans.

Bats are mammals, and are the only mammals capable of true, sustained flight. As mammals, they are warm-blooded, covered in fur, and nourish their young with milk. Their wings are unique extensions of their forelimbs, consisting of long, spread-out fingers with a thin membrane of skin stretching between them. Bats belong to the order Chiroptera, and there are over 1,300 species worldwide.

A bat is a type of mammal from the order Chiroptera, characterized by its ability to fly using wings formed by a membrane stretched between its long fingers and body. Like other mammals, bats are warm-blooded, have fur, and nourish their young with milk. They are the only mammals capable of true, sustained flight and play vital roles in ecosystems by controlling insect pests, pollinating plants, and spreading seeds.

Summary

A bat, (order Chiroptera) is any member of the only group of mammals capable of flight. This ability, coupled with the ability to navigate at night by using a system of acoustic orientation (echolocation), has made the bats a highly diverse and populous order. More than 1,200 species are currently recognized, and many are enormously abundant. Observers have concluded, for example, that some 100 million female Mexican free-tailed bats (Tadarida brasiliensis mexicana) form summer nursery colonies in Texas, where they produce about 100 million young in five large caves. The adult males are equal in number to the females, though they do not all range as far north as Texas. Furthermore, this species is found throughout tropical America. Thus, one species alone numbers, at the very least, in the hundreds of millions.

General features

All bats have a generally similar appearance in flight, dominated by the expanse of the wings, but they vary considerably in size. The order is usually divided into two well-defined suborders: the Megachiroptera (the large Old World fruit bats) and the Microchiroptera (small bats found worldwide). Among members of the Megachiroptera, flying foxes (Pteropus) have a wingspan of 1.5 metres (about 5 feet) and a weight of 1 kg (2.2 pounds). The largest insectivorous bat is probably the naked, or hairless, bat (Cheiromeles torquatus); it weighs about 250 grams (about 9 ounces). The largest of the carnivorous bats (and the largest bat in the New World) is the spectral bat (Vampyrum spectrum), also known as the tropical American false vampire bat, with a wingspan of over 60 cm (24 inches). The tiny hog-nosed, or bumblebee, bat (Craseonycteris thonglongyai) of Thailand is one of the smallest mammals. It has a wingspan of barely 15 cm (6 inches) and weighs about 2 grams (about 0.07 ounce).

Bats vary in colour and in fur texture. Facial appearance, dominated by the muzzle and ears, varies strikingly between families and often between genera. In several families a complex fleshy adornment called the nose leaf surrounds the nostrils. Although the exact function of these facial appurtenances has yet to be determined, scientists believe they may help to direct outgoing echolocation calls (see below Orientation). Wing proportions are modified according to mode of flight. The tail and the membrane between the legs also differ, perhaps as adaptations to feeding, flight, and roosting habits. Finally, bats vary in the postures they assume when roosting, particularly in whether they hang suspended or cling to a wall and in the manner in which the wings are folded and used.

Distribution

Bats are particularly abundant in the tropics. In West Africa, for example, more than 30 genera embracing nearly 100 species have been cataloged; in the United States 19 genera, totaling about 45 species, are known. Of the 18 bat families, 3—the vesper bats (family Vespertilionidae), free-tailed bats (family Molossidae), and horseshoe bats (family Rhinolophidae)—are well represented in the temperate zones. A few American leaf-nosed bats (family Phyllostomidae) range into mild temperate regions. Several vesper bats range well into Canada.

The Vespertilionidae are found worldwide except in the polar regions and on isolated islands. The brown bats of genus Myotis have a range almost equal to that of the entire order. The free-tailed bats and sheath-tailed bats (family Emballonuridae) also encircle the Earth but are restricted to the tropics and subtropics. The horseshoe bats extend throughout the Old World, the roundleaf bats (family Hipposideridae) and Old World fruit bats (family Pteropodidae) throughout the Old World tropics, and the leaf-nosed bats throughout the New World tropics and slightly beyond. The other families have more restricted ranges.

Details

For centuries, bats have been called sinister and spooky, likely because of their beady eyes and razor-sharp fangs. But there’s more to these nocturnal creatures than meets the eyes. There are more than 1,300 species of bats in the world, making them the second most common group of mammals after rodents. Some weigh less than a penny, while others have a wingspan of six feet, but all are impressive and vital members of their ecosystems.

Winging it

The scientific name for bats is Chiroptera, which is Greek for “hand wing.” That’s because bats have four long fingers and a thumb, each connected to the next by a thin layer of skin. They are the only mammals in the world that can fly, and they are remarkably good at it. Their flexible skin membrane and movable joints allow them to change direction quickly and catch mosquitoes in midair.

Classification

There are two main types of bats: microbats and megabats. Most bats are microbats, which eat insects like moths, that come out at night. Vampire bats are the only species of microbats that feed on blood rather than insects. But not to worry—they prefer to drink from cattle and horses, not humans.

To navigate dark caves and hunt after dark, microbats rely on echolocation, a system that allows them to locate objects using sound waves. They echolocate by making a high-pitched sound that travels until it hits an object and bounces back to them. This echo tells them an object’s size and how far away it is.

In contrast, megabats live in the tropics and eat fruit, nectar, and pollen. They have larger eyes and a stronger sense of smell than microbats but have smaller ears because they don’t echolocate. There are more than 150 species of megabats, which are usually, but not always, larger than microbats.

Roosting

Bats can be found nearly everywhere, except in polar regions, extreme deserts, and a few isolated islands. They spend their daylight hours hiding in roosts around the tropics, dense forests, and wetlands. Roosts are where bats go to rest, usually in cracks and crevices that keep them hidden and protected. The most common roosts are existing structures such as caves, tree hollows, and old buildings.

Seasons often dictate where any bats choose their homes. depending on the time of year because they hibernate during the winter. For example, in the winter, some may hibernate in caves, and in the summer, they’ll return to an attic. Because good roosts can be hard to find, many live in giant colonies with millions of other bats.

No matter where they spend their seasons, all bats roost upside down. They can hang from their hind feet and legs while resting. Scientists still aren’t sure why bats do this, but here’s one theory: Bats have to fall into flight, which makes hanging upside down the best way to escape quickly.

Nature’s conservationists

Despite all the misconceptions surrounding bats, they are very important to humans and the environment. Insect-eating microbats consume millions of bugs a night, acting as a natural pest control for plants. Thanks to bats, farmers might rely less on toxic pesticides, which costs them millions of dollars each year. Nectar-drinking bats pollinate plants so they can produce fruit. In fact, more than 500 plant species, including mangoes, bananas, and avocados, depend on bats for pollination. Finally, fruit-eating bats help disperse seeds so rainforests can grow, helping to mitigate the effects of widespread deforestation.

Additional Information

Bats are flying mammals of the order Chiroptera. With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out digits covered with a thin membrane or patagium. The smallest bat, and arguably the smallest extant mammal, is Kitti's hog-nosed bat, which is 29–34 mm (1.1–1.3 in) in length, 150 mm (5.9 in) across the wings and 2–2.6 g (0.071–0.092 oz) in mass. The largest bats are the flying foxes, with the giant golden-crowned flying fox (Acerodon jubatus) reaching a weight of 1.6 kg (3.5 lb) and having a wingspan of 1.7 m (5 ft 7 in).

The second largest order of mammals after rodents, bats comprise about 20% of all classified mammal species worldwide, with over 1,400 species. These were traditionally divided into two suborders: the largely fruit-eating megabats, and the echolocating microbats. But more recent evidence has supported dividing the order into Yinpterochiroptera and Yangochiroptera, with megabats as members of the former along with several species of microbats. Many bats are insectivores, and most of the rest are frugivores (fruit-eaters) or nectarivores (nectar-eaters). A few species feed on animals other than insects; for example, the vampire bats are haematophagous (feeding on blood). Most bats are nocturnal, and many roost in caves or other refuges; it is uncertain whether bats have these behaviours to escape predators. Bats are distributed globally in all except the coldest regions. They are important in their ecosystems for pollinating flowers and dispersing seeds; many tropical plants depend entirely on bats for these services. Globally, they transfer organic matter into cave ecosystems and arthropod suppression. Insectivory by bats in farmland constitutes an ecosystem service that has paramount value to humans: even in today’s pesticide era, natural enemies account for almost all pest suppression in farmed ecosystems.

Bats provide humans with some direct benefits, at the cost of some disadvantages. Bat dung has been mined as guano from caves and used as fertiliser. Bats consume insect pests, reducing the need for pesticides and other insect management measures. Some bats are also predators of mosquitoes, suppressing the transmission of mosquito-borne diseases. Bats are sometimes numerous enough and close enough to human settlements to serve as tourist attractions, and they are used as food across Asia and the Pacific Rim. However, fruit bats are frequently considered pests by fruit growers. Due to their physiology, bats are one type of animal that acts as a natural reservoir of many pathogens, such as rabies; and since they are highly mobile, social, and long-lived, they can readily spread disease among themselves. If humans interact with bats, these traits become potentially dangerous to humans.

Depending on the culture, bats may be symbolically associated with positive traits, such as protection from certain diseases or risks, rebirth, or long life, but in the West, bats are popularly associated with darkness, malevolence, witchcraft, vampires, and death.

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Jai Ganesh · Science HQ

Mercury (Element)

Gist

Mercury is a chemical element with the symbol Hg and atomic number 80. It is a heavy, silvery-white metal that is unique for being the only metallic element that remains liquid at standard temperature and pressure, though other metals like gallium melt just above room temperature. Also known as quicksilver, it forms alloys called amalgams with other metals and is found in nature in deposits of cinnabar. Mercury is toxic and can cause serious health problems, particularly to the nervous system, and bioaccumulates in the environment and food chains.

Mercury has historically been used in thermometers, barometers, electrical switches, fluorescent lamps, dental amalgams, and some batteries, pharmaceuticals, and cosmetics. However, due to its toxicity, many of these uses are being phased out in favor of alternatives, with the Minamata Convention on Mercury working to eliminate its use in products and industries globally.

Summary

Mercury is a chemical element; it has symbol Hg and atomic number 80. It is commonly known as quicksilver. A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.

Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the nervous system, immune system and kidneys of humans and other animals; mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury) either directly or through mechanisms of biomagnification.

Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, although concerns about the element's toxicity have led to the phasing out of such mercury-containing instruments. It remains in use in scientific research applications and in amalgam for dental restoration in some locales. It is also used in fluorescent lighting. Electricity passed through mercury vapor in a fluorescent lamp produces short-wave ultraviolet light, which then causes the phosphor in the tube to fluoresce, making visible light.

Details

Mercury (Hg) is a chemical element, liquid metal of Group 12 (IIb, or zinc group) of the periodic table.

Element Properties

atomic number : 80
atomic weight : 200.592
melting point : -38.83 °C (-37.89 °F)
boiling point : 356.62 °C (673.91 °F)
specific gravity : 13.5 at 20 °C (68 °F)
valence : 1, 2.

Properties, uses, and occurrence

Mercury was known in Egypt and also probably in the East as early as 1500 bce. The name mercury originated in 6th-century alchemy, in which the symbol of the planet was used to represent the metal; the chemical symbol Hg derives from the Latin hydrargyrum, “liquid silver.” Although its toxicity was recognized at an early date, its main application was for medical purposes.

Mercury is the only elemental metal that is liquid at room temperature. (Cesium melts at about 28.5 °C [83 °F], gallium at about 30 °C [86 °F], and rubidium at about 39 °C [102 °F].) Mercury is silvery white, slowly tarnishes in moist air, and freezes into a soft solid like tin or lead at −38.83 °C (−37.89 °F). It boils at 356.62 °C (673.91 °F).

It alloys with copper, tin, and zinc to form amalgams, or liquid alloys. An amalgam with silver is used as a filling in dentistry. Mercury does not wet glass or cling to it, and this property, coupled with its rapid and uniform volume expansion throughout its liquid range, made it useful in thermometers. (Mercury thermometers were supplanted by more accurate electronic digital thermometers in the early 21st century.) Barometers and manometers also used its high density and low vapour pressure. However, mercury’s toxicity has led to its replacement in these instruments. Gold and silver dissolve readily in mercury, and in the past this property was used in the extraction of these metals from their ores.

The good electrical conductivity of mercury makes it exceptionally useful in sealed electrical switches and relays. An electrical discharge through mercury vapour contained in a fused silica tube or bulb produces a bluish glow rich in ultraviolet light, a phenomenon exploited in ultraviolet, fluorescent, and high-pressure mercury-vapour lamps. Some mercury is used in the preparation of pharmaceuticals and agricultural and industrial fungicides.

In the 20th century the use of mercury in the manufacture of chlorine and sodium hydroxide by electrolysis of brine depended upon the fact that mercury employed as the negative pole, or cathode, dissolves the sodium liberated to form a liquid amalgam. In the early 21st century, however, mercury-cell plants for manufacturing chlorine and sodium hydroxide have mostly been phased out.

Mercury occurs in Earth’s crust on the average of about 0.08 gram (0.003 ounce) per ton of rock. The principal ore is the red sulfide, cinnabar. Native mercury occurs in isolated drops and occasionally in larger fluid masses, usually with cinnabar, near volcanoes or hot springs. Extremely rare natural alloys of mercury have also been found: moschellandsbergite (with silver), potarite (with palladium), and gold amalgam. Over 90 percent of the world’s supply of mercury comes from China; it is often a by-product of gold mining.

Cinnabar is mined in shaft or open-pit operations and refined by flotation. Most of the methods of extraction of mercury rely on the volatility of the metal and the fact that cinnabar is readily decomposed by air or by lime to yield the free metal. Mercury is extracted from cinnabar by roasting it in air, followed by condensation of the mercury vapour. Because of the toxicity of mercury and the threat of rigid pollution control, attention is being directed toward safer methods of extracting mercury. These generally rely on the fact that cinnabar is readily soluble in solutions of sodium hypochlorite or sulfide, from which the mercury can be recovered by precipitation with zinc or aluminum or by electrolysis.

Mercury is toxic. Poisoning may result from inhalation of the vapour, ingestion of soluble compounds, or absorption of mercury through the skin.

Natural mercury is a mixture of seven stable isotopes: 196Hg (0.15 percent), 198Hg (9.97 percent), 199Hg (16.87 percent), 200Hg (23.10 percent), 201Hg (13.18 percent), 202Hg (29.86 percent), and 204Hg (6.87 percent). Isotopically pure mercury consisting of only mercury-198 prepared by neutron bombardment of natural gold, gold-197, has been used as a wavelength standard and for other precise work.

Principal compounds

The compounds of mercury are either of +1 or +2 oxidation state. Mercury(II) or mercuric compounds predominate. Mercury does not combine with oxygen to produce mercury(II) oxide, HgO, at a useful rate until heated to the range of 300 to 350 °C (572 to 662 °F). At temperatures of about 400 °C (752 °F) and above, the reaction reverses with the compound decomposing into its elements. Antoine-Laurent Lavoisier and Joseph Priestley used this reaction in their study of oxygen.

There are relatively few mercury(I) or mercurous compounds. The mercury(I) ion, Hg22+, is diatomic and stable. Mercury(I) chloride, Hg2Cl2 (commonly known as calomel), is probably the most important univalent compound. It was used in antiseptic salves. Mercury(II) chloride, HgCl2 (also called bichloride of mercury or corrosive sublimate), is perhaps the commonest bivalent compound. Although extremely toxic, this odourless, colourless substance has a wide variety of applications. In agriculture it is used as a fungicide, in medicine it was sometimes employed as a topical antiseptic in concentrations of one part per 2,000 parts of water, and in the chemical industry it serves as a catalyst in the manufacture of vinyl chloride and as a starting material in the production of other mercury compounds. Mercury(II) oxide, HgO, provides elemental mercury for the preparation of various organic mercury compounds and certain inorganic mercury salts. This red or yellow crystalline solid is also used as an electrode (mixed with graphite) in zinc-mercuric oxide electric cells and in mercury batteries. Mercury(II) sulfide, HgS, is a black or red crystalline solid used chiefly as a pigment in paints, rubber, and plastics.

Additional Information:

Appearance

A liquid, silvery metal.

Uses

Mercury has fascinated people for millennia, as a heavy liquid metal. However, because of its toxicity, many uses of mercury are being phased out or are under review.

It is now mainly used in the chemical industry as catalysts. It is also used in some electrical switches and rectifiers.

Previously its major use was in the manufacture of sodium hydroxide and chlorine by electrolysis of brine. These plants will all be phased out by 2020. It was also commonly used in batteries, fluorescent lights, felt production, thermometers and barometers. Again, these uses have been phased out.

Mercury easily forms alloys, called amalgams, with other metals such as gold, silver and tin. The ease with which it amalgamates with gold made it useful in recovering gold from its ores. Mercury amalgams were also used in dental fillings.

Mercuric sulfide (vermilion) is a high-grade, bright-red paint pigment, but is very toxic so is now only used with great care.

Biological role

Mercury has no known biological role, but is present in every living thing and widespread in the environment. Every mouthful of food we eat contains a little mercury.

Our daily intake is less than 0.01 milligrams (about 0.3 grams in a lifetime), and this we can cope with easily. However, in much higher doses it is toxic and one form of mercury – methylmercury – is particularly dangerous. It can accumulate in the flesh of fish and be eaten by people, making them ill.

Natural abundance

Mercury rarely occurs uncombined in nature, but can be found as droplets in cinnabar (mercury sulfide) ores. China and Kyrgyzstan are the main producers of mercury. The metal is obtained by heating cinnabar in a current of air and condensing the vapour.

Jai Ganesh · Exercises

Hi,

2581.

Jai Ganesh · Jai Ganesh's Puzzles

Hi,

#6238.

Math Is Fun Forum

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