title: Spin (physics)

text: For a given quantum state, one could think of a spin vector formula_8 whose components are the expectation values of the spin components along each axis, i.e., formula_9. This vector then would describe the "direction" in which the spin is pointing, corresponding to the classical concept of the axis of rotation. It turns out that the spin vector is not very useful in actual quantum-mechanical calculations, because it cannot be measured directly: , and cannot possess simultaneous definite values, because of a quantum uncertainty relation between them. However, for statistically large collections of particles that have been placed in the same pure quantum state, such as through the use of a Stern–Gerlach apparatus, the spin vector does have a well-defined experimental meaning: It specifies the direction in ordinary space in which a subsequent detector must be oriented in order to achieve the maximum possible probability (100%) of detecting every particle in the collection. For spin- particles, this probability drops off smoothly as the angle between the spin vector and the detector increases, until at an angle of 180°—that is, for detectors oriented in the opposite direction to the spin vector—the expectation of detecting particles from the collection reaches a minimum of 0%.


title: Spin (physics)

text: As a qualitative concept, the spin vector is often handy because it is easy to picture classically. For instance, quantum-mechanical spin can exhibit phenomena analogous to classical gyroscopic effects. For example, one can exert a kind of "torque" on an electron by putting it in a magnetic field (the field acts upon the electron's intrinsic magnetic dipole moment—see the following section). The result is that the spin vector undergoes precession, just like a classical gyroscope. This phenomenon is known as electron spin resonance (ESR). The equivalent behaviour of protons in atomic nuclei is used in nuclear magnetic resonance (NMR) spectroscopy and imaging.


title: Spin (physics)

text: Mathematically, quantum-mechanical spin states are described by vector-like objects known as spinors. There are subtle differences between the behavior of spinors and vectors under coordinate rotations. For example, rotating a spin- particle by 360° does not bring it back to the same quantum state, but to the state with the opposite quantum phase; this is detectable, in principle, with interference experiments. To return the particle to its exact original state, one needs a 720° rotation. (The Plate trick and Möbius strip give non-quantum analogies.) A spin-zero particle can only have a single quantum state, even after torque is applied. Rotating a spin-2 particle 180° can bring it back to the same quantum state, and a spin-4 particle should be rotated 90° to bring it back to the same quantum state. The spin-2 particle can be analogous to a straight stick that looks the same even after it is rotated 180°, and a spin-0 particle can be imagined as sphere, which looks the same after whatever angle it is turned through.


title: Spin (physics)

text: where is the Levi-Civita symbol. It follows (as with angular momentum) that the eigenvectors of formula_11 and formula_12 (expressed as kets in the total basis) are


title: Spin (physics)

text: But unlike orbital angular momentum, the eigenvectors are not spherical harmonics. They are not functions of and . There is also no reason to exclude half-integer values of and .


title: Spin (physics)

text: All quantum-mechanical particles possess an intrinsic spin formula_16 (though this value may be equal to zero). The projection of the spin formula_16 on any axis is quantized in units of the reduced Planck constant, such that the state function of the particle is, say, not formula_18, but formula_19, where formula_20 can take only the values of the following discrete set:


title: Spin (physics)

text: One distinguishes bosons (integer spin) and fermions (half-integer spin). The total angular momentum conserved in interaction processes is then the sum of the orbital angular momentum and the spin.


title: Spin (physics)

text: For systems of identical particles this is related to the Pauli exclusion principle, which states that its wavefunction formula_25 must change upon interchanges of any two of the particles as


title: Spin (physics)

text: Thus, for bosons the prefactor will reduce to +1, for fermions to −1. In quantum mechanics all particles are either bosons or fermions. In some speculative relativistic quantum field theories "supersymmetric" particles also exist, where linear combinations of bosonic and fermionic components appear. In two dimensions, the prefactor can be replaced by any complex number of magnitude 1 such as in the anyon.


title: Spin (physics)

text: The above permutation postulate for -particle state functions has most important consequences in daily life, e.g. the periodic table of the chemical elements.


title: Spin (physics)

text: As described above, quantum mechanics states that components of angular momentum measured along any direction can only take a number of discrete values. The most convenient quantum-mechanical description of particle's spin is therefore with a set of complex numbers corresponding to amplitudes of finding a given value of projection of its intrinsic angular momentum on a given axis. For instance, for a spin- particle, we would need two numbers , giving amplitudes of finding it with projection of angular momentum equal to and , satisfying the requirement


title: Spin (physics)

text: For a generic particle with spin , we would need such parameters. Since these numbers depend on the choice of the axis, they transform into each other non-trivially when this axis is rotated. It is clear that the transformation law must be linear, so we can represent it by associating a matrix with each rotation, and the product of two transformation matrices corresponding to rotations A and B must be equal (up to phase) to the matrix representing rotation AB. Further, rotations preserve the quantum-mechanical inner product, and so should our transformation matrices:


title: Spin (physics)

text: Mathematically speaking, these matrices furnish a unitary projective representation of the rotation group SO(3). Each such representation corresponds to a representation of the covering group of SO(3), which is SU(2). There is one -dimensional irreducible representation of SU(2) for each dimension, though this representation is -dimensional real for odd and -dimensional complex for even (hence of real dimension ). For a rotation by angle in the plane with normal vector formula_30,


title: Spin (physics)

text: A generic rotation in 3-dimensional space can be built by compounding operators of this type using Euler angles:


title: Spin (physics)

text: is Wigner's small d-matrix. Note that for and ; i.e., a full rotation about the  axis, the Wigner D-matrix elements become


title: Spin (physics)

text: Recalling that a generic spin state can be written as a superposition of states with definite , we see that if is an integer, the values of are all integers, and this matrix corresponds to the identity operator. However, if is a half-integer, the values of are also all half-integers, giving for all , and hence upon rotation by 2 the state picks up a minus sign. This fact is a crucial element of the proof of the spin–statistics theorem.


title: Spin (physics)

text: We could try the same approach to determine the behavior of spin under general Lorentz transformations, but we would immediately discover a major obstacle. Unlike SO(3), the group of Lorentz transformations SO(3,1) is non-compact and therefore does not have any faithful, unitary, finite-dimensional representations.


title: Spin (physics)

text: In case of spin- particles, it is possible to find a construction that includes both a finite-dimensional representation and a scalar product that is preserved by this representation. We associate a 4-component Dirac spinor with each particle. These spinors transform under Lorentz transformations according to the law


title: Spin (physics)

text: where are gamma matrices, and is an antisymmetric 4 × 4 matrix parametrizing the transformation. It can be shown that the scalar product


title: Spin (physics)

text: Each of the (Hermitian) Pauli matrices of spin- particles has two eigenvalues, +1 and −1. The corresponding normalized eigenvectors are


title: Spin (physics)

text: By the postulates of quantum mechanics, an experiment designed to measure the electron spin on the , , or  axis can only yield an eigenvalue of the corresponding spin operator (, or ) on that axis, i.e. or . The quantum state of a particle (with respect to spin), can be represented by a two-component spinor:


title: Spin (physics)

text: When the spin of this particle is measured with respect to a given axis (in this example, the  axis), the probability that its spin will be measured as is just formula_41. Correspondingly, the probability that its spin will be measured as is just formula_42. Following the measurement, the spin state of the particle collapses into the corresponding eigenstate. As a result, if the particle's spin along a given axis has been measured to have a given eigenvalue, all measurements will yield the same eigenvalue (since formula_43, etc.), provided that no measurements of the spin are made along other axes.


title: Spin (physics)

text: The operator to measure spin along an arbitrary axis direction is easily obtained from the Pauli spin matrices. Let be an arbitrary unit vector. Then the operator for spin in this direction is simply


title: Spin (physics)

text: The operator has eigenvalues of , just like the usual spin matrices. This method of finding the operator for spin in an arbitrary direction generalizes to higher spin states, one takes the dot product of the direction with a vector of the three operators for the three -, -, -axis directions.


title: Spin (physics)

text: A normalized spinor for spin- in the direction (which works for all spin states except spin down, where it will give ) is


title: Spin (physics)

text: The above spinor is obtained in the usual way by diagonalizing the matrix and finding the eigenstates corresponding to the eigenvalues. In quantum mechanics, vectors are termed "normalized" when multiplied by a normalizing factor, which results in the vector having a length of unity.


title: Spin (physics)

text: Since the Pauli matrices do not commute, measurements of spin along the different axes are incompatible. This means that if, for example, we know the spin along the  axis, and we then measure the spin along the  axis, we have invalidated our previous knowledge of the  axis spin. This can be seen from the property of the eigenvectors (i.e. eigenstates) of the Pauli matrices that


title: Spin (physics)

text: So when physicists measure the spin of a particle along the  axis as, for example, , the particle's spin state collapses into the eigenstate formula_47. When we then subsequently measure the particle's spin along the  axis, the spin state will now collapse into either formula_48 or formula_49, each with probability . Let us say, in our example, that we measure . When we now return to measure the particle's spin along the  axis again, the probabilities that we will measure or are each (i.e. they are formula_50 and formula_51 respectively). This implies that the original measurement of the spin along the  axis is no longer valid, since the spin along the  axis will now be measured to have either eigenvalue with equal probability.


title: Spin (physics)

text: The spin- operator forms the fundamental representation of SU(2). By taking Kronecker products of this representation with itself repeatedly, one may construct all higher irreducible representations. That is, the resulting spin operators for higher-spin systems in three spatial dimensions can be calculated for arbitrarily large using this spin operator and ladder operators. For example, taking the Kronecker product of two spin- yields a four-dimensional representation, which is separable into a 3-dimensional spin-1 (triplet states) and a 1-dimensional spin-0 representation (singlet state).


title: Spin (physics)

text: The resulting irreducible representations yield the following spin matrices and eigenvalues in the z-basis:


title: Spin (physics)

text: Also useful in the quantum mechanics of multiparticle systems, the general Pauli group is defined to consist of all -fold tensor products of Pauli matrices.


title: Spin (physics)

text: In tables of the spin quantum number for nuclei or particles, the spin is often followed by a "+" or "−". This refers to the parity with "+" for even parity (wave function unchanged by spatial inversion) and "−" for odd parity (wave function negated by spatial inversion). For example, see the isotopes of bismuth, in which the list of isotopes includes the column nuclear spin and parity. For Bi-209, the only stable isotope, the entry 9/2– means that the nuclear spin is 9/2 and the parity is odd.


title: Spin (physics)

text: Spin has important theoretical implications and practical applications. Well-established "direct" applications of spin include:


title: Spin (physics)

text: Electron spin plays an important role in magnetism, with applications for instance in computer memories. The manipulation of "nuclear spin" by radio-frequency waves (nuclear magnetic resonance) is important in chemical spectroscopy and medical imaging.


title: Spin (physics)

text: Spin–orbit coupling leads to the fine structure of atomic spectra, which is used in atomic clocks and in the modern definition of the second. Precise measurements of the -factor of the electron have played an important role in the development and verification of quantum electrodynamics. "Photon spin" is associated with the polarization of light (photon polarization).


title: Spin (physics)

text: An emerging application of spin is as a binary information carrier in spin transistors. The original concept, proposed in 1990, is known as Datta–Das spin transistor. Electronics based on spin transistors are referred to as spintronics. The manipulation of spin in dilute magnetic semiconductor materials, such as metal-doped ZnO or TiO imparts a further degree of freedom and has the potential to facilitate the fabrication of more efficient electronics.


title: Spin (physics)

text: There are many "indirect" applications and manifestations of spin and the associated Pauli exclusion principle, starting with the periodic table of chemistry.


title: Spin (physics)

text: Spin was first discovered in the context of the emission spectrum of alkali metals. In 1924, Wolfgang Pauli introduced what he called a "two-valuedness not describable classically" associated with the electron in the outermost shell. This allowed him to formulate the Pauli exclusion principle, stating that no two electrons can have the same quantum state in the same quantum system.


title: Spin (physics)

text: The physical interpretation of Pauli's "degree of freedom" was initially unknown. Ralph Kronig, one of Landé's assistants, suggested in early 1925 that it was produced by the self-rotation of the electron. When Pauli heard about the idea, he criticized it severely, noting that the electron's hypothetical surface would have to be moving faster than the speed of light in order for it to rotate quickly enough to produce the necessary angular momentum. This would violate the theory of relativity. Largely due to Pauli's criticism, Kronig decided not to publish his idea.


title: Spin (physics)

text: In the autumn of 1925, the same thought came to Dutch physicists George Uhlenbeck and Samuel Goudsmit at Leiden University. Under the advice of Paul Ehrenfest, they published their results. It met a favorable response, especially after Llewellyn Thomas managed to resolve a factor-of-two discrepancy between experimental results and Uhlenbeck and Goudsmit's calculations (and Kronig's unpublished results). This discrepancy was due to the orientation of the electron's tangent frame, in addition to its position.


title: Spin (physics)

text: Mathematically speaking, a fiber bundle description is needed. The tangent bundle effect is additive and relativistic; that is, it vanishes if goes to infinity. It is one half of the value obtained without regard for the tangent-space orientation, but with opposite sign. Thus the combined effect differs from the latter by a factor two (Thomas precession, known to Ludwik Silberstein in 1914).


title: Spin (physics)

text: Despite his initial objections, Pauli formalized the theory of spin in 1927, using the modern theory of quantum mechanics invented by Schrödinger and Heisenberg. He pioneered the use of Pauli matrices as a representation of the spin operators and introduced a two-component spinor wave-function. Uhlenbeck and Goudsmit treated spin as arising from classical rotation, while Pauli emphasized, that spin is non-classical and intrinsic property.


title: Spin (physics)

text: Pauli's theory of spin was non-relativistic. However, in 1928, Paul Dirac published the Dirac equation, which described the relativistic electron. In the Dirac equation, a four-component spinor (known as a "Dirac spinor") was used for the electron wave-function. Relativistic spin explained gyromagnetic anomaly, which was (in retrospect) first observed by Samuel Jackson Barnett in 1914 (see Einstein–de Haas effect). In 1940, Pauli proved the "spin–statistics theorem", which states that fermions have half-integer spin, and bosons have integer spin.


title: Spin (physics)

text: In retrospect, the first direct experimental evidence of the electron spin was the Stern–Gerlach experiment of 1922. However, the correct explanation of this experiment was only given in 1927.


title: Yellow River

text: The Yellow River or Huang He (Chinese: , Mandarin: "Huáng hé" ) is the second-longest river in China, after the Yangtze River, and the sixth-longest river system in the world at the estimated length of . Originating in the Bayan Har Mountains in Qinghai province of Western China, it flows through nine provinces, and it empties into the Bohai Sea near the city of Dongying in Shandong province. The Yellow River basin has an east–west extent of about and a north–south extent of about . Its total drainage area is about .


title: Yellow River

text: The Yellow River's basin was the birthplace of ancient Chinese, and, by extension, Far Eastern civilization, and it was the most prosperous region in early Chinese history. There are frequent devastating floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fields.


title: Yellow River

text: Early Chinese literature including the "Yu Gong" or "Tribute of Yu" dating to the Warring States period (475–221 BC) refers to the Yellow River as simply (Old Chinese: "*C.gˤaj", Modern Beijing Mandarin: // or in pinyin "Hé"), a character that has come to mean "river" in modern usage. An early attestation of the name (Eastern Han Chinese: "*ɣuaŋ-gɑi"; Middle Chinese: "Huang Ha") in the Eastern Han treatise "Kongcongzi" 孔叢子 "The Many Kong Family Master's Anthology", attributed to Confucius' descendant Kong Fu 孔鮒 (c. 264-208 BCE). The adjective "yellow" describes the perennial color of the muddy water in the lower course of the river, which arises from soil (loess) being carried downstream. Its yellow colour and central position in China are associated in traditional cardinal directions.


title: Yellow River

text: One of its older Mongolian names was the "Black River", because the river runs clear before it enters the Loess Plateau, but the current name of the river among Inner Mongolians is "Ȟatan Gol" (, "Queen River"). In Mongolia itself, it is simply called the "Šar Mörön" (, "Yellow River"). The river is mentioned in the Kul Tigin stele as the "Green River" (Old Turkic : "yašïl ügüz", 𐰖𐱁𐰞𐰽𐰺𐰍).


title: Yellow River

text: The Yellow river first formed between 56 million and 34 million years ago during the Eocene epoch, while the familar shape appeared around 7 thousand years ago.


title: Yellow River

text: The river has long been critical to the development of northern China, and is regarded by scholars as one cradle of civilization. Flooding of the river has also caused much destruction, including multiple floods that have resulted in the deaths of over one million people. Among the deadliest were the 1332–33 flood during the Yuan dynasty, the 1887 flood during the Qing dynasty which killed anywhere from 900,000 to 2 million people, and a Republic of China era 1931 flood (part of a massive number of floods that year) that killed 1–4 million people.


title: Yellow River

text: The cause of the floods is the large amount of fine-grained loess carried by the river from the Loess Plateau, which is continuously deposited along the bottom of its channel. The sedimentation causes natural dams to slowly accumulate. These subaqueous dams are unpredictable and generally undetectable. Eventually, the enormous amount of water needs to find a new way to the sea, forcing it to take the path of least resistance. When this happens, it bursts out across the flat North China Plain, sometimes taking a new channel and inundating most farmland, cities or towns in its path.


title: Yellow River

text: The traditional Chinese response of building higher and higher levees along the banks sometimes also contributed to the severity of the floods: When flood water did break through the levees, it could no longer drain back into the river bed as it would after a normal flood, as the river bed was sometimes now higher than the surrounding countryside. These changes could cause the river's mouth to shift as much as , sometimes reaching the ocean to the north of Shandong Peninsula and sometimes to the south.


title: Yellow River

text: Another historical source of devastating floods is the collapse of upstream ice dams in Inner Mongolia with an accompanying sudden release of vast quantities of impounded water. There have been 11 such major floods in the past century, each causing tremendous loss of life and property. Nowadays, explosives dropped from aircraft are used to break the ice dams before they become dangerous.


title: Yellow River

text: Before modern dams appeared in China, the Yellow River used to be extremely prone to flooding. In the 2,540 years from 595 BC to 1946 AD, the Yellow River has been reckoned to have flooded 1,593 times, shifting its course 26 times noticeably and nine times severely. These floods include some of the deadliest natural disasters ever recorded. Before modern disaster management, when floods occurred, some of the population might initially die from drowning and many more would suffer later from the ensuing famine and spread of diseases.


title: Yellow River

text: In Chinese mythology, the giant Kua Fu drained the Yellow River and the Wei River to quench his burning thirst as he pursued the Sun. Historical documents from the Spring and Autumn period and Qin dynasty indicate that the Yellow River at that time flowed considerably north of its present course. These accounts show that after the river passed Luoyang, it flowed along the border between Shanxi and Henan Provinces, then continued along the border between Hebei and Shandong before emptying into Bohai Bay near present-day Tianjin. Another outlet followed essentially the present course.


title: Yellow River

text: The river left these paths in 602 BC and shifted several hundred kilometers to the east. Sabotage of dikes, canals, and reservoirs and deliberate flooding of rival states became a standard military tactic during the Warring States period. As the Yellow River valley was the major entryway to the Guanzhong area and the state of Qin from the North China Plain, Qin heavily fortified the Hangu Pass; it saw numerous battles and was also an important chokepoint protecting the Han capitals of Chang'an and Luoyang. Major flooding in AD 11 is credited with the downfall of the short-lived Xin dynasty, and another flood in AD 70 returned the river north of Shandong on essentially its present course.


title: Yellow River

text: From around the beginning of the 3rd century, the importance of the Hangu Pass was reduced, with the major fortifications and military bases moved upriver to Tongguan. In AD 923, the desperate Later Liang general Duan Ning again broke the dikes, flooding in a failed attempt to protect his realm's capital from the Later Tang. A similar proposal from the Song engineer Li Chun concerning flooding the lower reaches of the river to protect the central plains from the Khitai was overruled in 1020: the Chanyuan Treaty between the two states had expressly forbidden the Song from establishing new moats or changing river courses.


title: Yellow River

text: Breaches occurred regardless: one at Henglong in 1034 divided the course in three and repeatedly flooded the northern regions of Dezhou and Bozhou. The Song worked for five years futilely attempting to restore the previous courseusing over 35,000 employees, 100,000 conscripts, and 220,000 tons of wood and bamboo in a single yearbefore abandoning the project in 1041. The more sluggish river then occasioned a breach at Shanghu that sent the main outlet north towards Tianjin in 1048


title: Yellow River

text: In 1128, the Song troops breached the southern dikes of the Yellow River in an effort to stop the advancing Jin army. The resulting major river avulsion allowed the Yellow to capture tributaries of the Huai River. For the first time in recorded history, the Yellow River shifted completely south of Shandong Peninsula and flowed into the Yellow Sea. By 1194, the mouth of the Huai had been blocked. The buildup of silt deposits was such that even after the Yellow River later shifted its course, the Huai could no longer flow along its historic course, but instead, its water pools into Hongze Lake and then runs southward toward the Yangtze River.


title: Yellow River

text: A flood in 1344 returned the Yellow River south of Shandong. The Yuan dynasty was waning, and the emperor forced enormous teams to build new embankments for the river. The terrible conditions helped to fuel rebellions that led to the founding of the Ming dynasty. The course changed again in 1391 when the river flooded from Kaifeng to Fengyang in Anhui. It was finally stabilized by the eunuch Li Xing during the public works projects following the 1494 flood. The river flooded many times in the 16th century, including in 1526, 1534, 1558, and 1587. Each flood affected the river's lower course.


title: Yellow River

text: The 1642 flood was man-made, caused by the attempt of the Ming governor of Kaifeng to use the river to destroy the peasant rebels under Li Zicheng who had been besieging the city for the past six months. He directed his men to break the dikes in an attempt to flood the rebels, but destroyed his own city instead: the flood and the ensuing famine and plague are estimated to have killed 300,000 of the city's previous population of 378,000. The once-prosperous city was nearly abandoned until its rebuilding under the Kangxi Emperor in the Qing dynasty.


title: Yellow River

text: The question of how aggressively flooding should be controlled, and whether it should be steered back to its original channels when it migrated, was a topic of controversy in the imperial court. Rival cliques made arguments based on budgetary, technical and strategic criteria. Geographer Charles Greer identifies two competing schools of thought on how to control the Yellow River. One, which he identifies as Confucian, advocated containing the river between higher levees, thus maximizing the amount of river basin land that could be cultivated. The other, which he associates with Taoism, favored lower levees separated by as much as 5-10 kilometers. In one particular long-running debate during the 11th century reigns of the Renzong and Shenzong emperors, when the river repeatedly broke its levees and migrated north and west, officials battled over whether expensive measures should be taken to return the river to its former channels. The Shenzong emperor ultimately decreed that the river be allowed to remain in its new course.


title: Yellow River

text: Traditional flood control techniques made use of levees, revetments to absorb the energy of the water, overflow basins, drainage canals and polders. Treatises on traditional flood control techniques were written by officials such as Pan Jixun (1528-1599), who argued that joining branches of the river increased the water's power and this in turn increased its ability to flush sediment.


title: Yellow River

text: Between 1851 and 1855, the Yellow River returned to the north amid the floods that provoked the Nien and Taiping Rebellions. The 1887 flood has been estimated to have killed between 900,000 and 2 million people, and is the second-worst natural disaster in history (excluding famines and epidemics). The Yellow River more or less adopted its present course during the 1897 flood.


title: Yellow River

text: The 1931 flood killed an estimated 1,000,000 to 4,000,000, and is the worst natural disaster recorded (excluding famines and epidemics).


title: Yellow River

text: On 9 June 1938, during the Second Sino-Japanese War, Nationalist troops under Chiang Kai-shek broke the levees holding back the river near the village of Huayuankou in Henan, causing what has been called by Canadian historian, Diana Lary, a "war-induced natural disaster". The goal of the operation was to stop the advancing Japanese troops by following a strategy of "using water as a substitute for soldiers" ("yishui daibing"). The 1938 flood of an area covering took some 500,000 to 900,000 Chinese lives, along with an unknown number of Japanese soldiers. The flood prevented the Japanese Army from taking Zhengzhou, on the southern bank of the Yellow River, but did not stop them from reaching their goal of capturing Wuhan, which was the temporary seat of the Chinese government and straddles the Yangtze River.


title: Yellow River

text: According to the China Exploration and Research Society, the source of the Yellow River is at in the Bayan Har Mountains near the eastern edge of the Yushu Tibetan Autonomous Prefecture. The source tributaries drain into Gyaring Lake and Ngoring Lake on the western edge of Golog Prefecture high in the Bayan Har Mountains of Qinghai. In the Zoige Basin along the boundary with Gansu, the Yellow River loops northwest and then northeast before turning south, creating the "Ordos Loop", and then flows generally eastward across the North China Plain to the Gulf of Bohai, draining a basin of which nourishes 140 million people with drinking water and irrigation.


title: Yellow River

text: The Yellow River passes through seven present-day provinces and two autonomous regions, namely (from west to east) Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan, and Shandong. Major cities along the present course of the Yellow River include (from west to east) Lanzhou, Yinchuan, Wuhai, Baotou, Luoyang, Zhengzhou, Kaifeng, and Jinan. The current mouth of the Yellow River is located at Kenli County, Shandong.


title: Yellow River

text: The river is commonly divided into three stages. These are roughly the northeast of the mountainous Tibetan Plateau, the Ordos Loop and Loess Plateau, and the North China Plain. However, different scholars have different opinions on how the three stages are divided. This article mainly adopts the division used by the Yellow River Conservancy Commission.


title: Yellow River

text: The Yellow River derived sediments have been transported out of the Bohai Sea, all way to the North Yellow Sea and South Yellow Sea, and formed a Distal Depocenter around the Shandong Peninsula.


title: Yellow River

text: The upper reaches of the Yellow River constitute a segment starting from its source in the Bayan Har Mountains and ending at Hekou Town (Togtoh County), Inner Mongolia just before it turns sharply to the south. This segment has a total length of and total basin area of , 51.4% of the total basin area. Along this length, the elevation of the Yellow River drops , with an average grade of 0.10%.


title: Yellow River

text: The source section flows mainly through pastures, swamps, and knolls between the Bayan Har Mountains, and the Anemaqen (Amne Machin) Mountains in Qinghai. The river water is clear and flows steadily. Crystal clear lakes are characteristic of this section. The two main lakes along this section are Lake Gyaring (Zhaling) and Lake Ngoring (Eling), with capacities of 4.7 billion and 10.8 billion m (166 and 381 billion ft), respectively. At elevations over ) above sea level they are the two largest plateau freshwater lakes nationwide. A significant amount of land in the Yellow River's source area has been designated as the Sanjiangyuan ("'Three Rivers' Sources") National Nature Reserve, to protect the source region of the Yellow River, the Yangtze, and the Mekong.


title: Yellow River

text: Flowing east at the eastern edge of the Amne Machin Mountains, the Yellow River enters Maqu County in Gansu. Here, the river skirts through the high-altitude peat bog known as the Zoigê Wetlands and makes a sharp turn towards the northwest forming the border between Maqu and Zoigê County in Sichuan. Flowing now along the northern edge of Amne Machin, the river reenters Qinghai and gradually curves north towards the Longyang Gorge at Xinghai.


title: Yellow River

text: The valley section stretches from Longyang Gorge in Qinghai to Qingtong Gorge in Gansu. Steep cliffs line both sides of the river. The water bed is narrow and the average drop is large, so the flow in this section is extremely turbulent and fast. There are 20 gorges in this section, the most famous of these being the Longyang, Jishi, Liujia, Bapan, and Qingtong gorges. The flow conditions in this section makes it the best location for hydroelectric plants. The Yellow River exits Qinghai for the second and final time in these gorges and enters Gansu for the second time just before Liujia Gorge. Downstream from the Yanguo Gorge, the provincial capital of Lanzhou is built upon the Yellow River's banks. The Yellow River flows northeasterly out of Gansu and into Ningxia before the Qingtong Gorge.


title: Yellow River

text: After emerging from the Qingtong Gorge, the river comes into a section of vast alluvial plains, the Yinchuan Plain and Hetao Plain. In this section, the regions along the river are mostly deserts and grasslands, with very few tributaries. The flow is slow. The Hetao Plain has a length of and width of . It is historically the most important irrigation plain along the Yellow River.


title: Yellow River

text: The Ordos Loop formed by an enormous twist of the Yellow River, beginning at Zhongning County in Ningxia and ending with a drastic eastward turn at its confluence with the Wei at Tongguan in Shaanxi. However, the official division for the middle reaches of the river run from Hekou in Togtoh County, Inner Mongolia, to Zhengzhou, Henan. The middle reaches are long, with a basin area of , 45.7% of the total, with a total elevation drop of , an average drop of 0.074%. There are 30 large tributaries along the middle reaches, and the water flow is increased by 43.5% on this stage. The middle reaches contribute 92% of the river's silts.


title: Yellow River

text: The middle stream of the Yellow River passes through the Loess Plateau, where substantial erosion takes place. The large amount of mud and sand discharged into the river makes the Yellow River the most sediment-laden river in the world. The highest recorded annual level of silts discharged into the Yellow River is 3.91 billion tons in 1933. The highest silt concentration level was recorded in 1977 at 920 kg/m (57.4 lb/ft). These sediments later deposit in the slower lower reaches of the river, elevating the river bed and creating the famous "river above ground". From Hekou to Yumenkou, the river passes through the longest series of continuous valleys on its main course, collectively called the Jinshan Valley. The abundant hydrodynamic resources stored in this section make it the second most suitable area to build hydroelectric power plants. The famous Hukou Waterfall is in the lower part of this valley on the border of Shanxi and Shaanxi.


title: Yellow River

text: In the lower reaches, from Zhengzhou, Henan to its mouth, a distance of , the river is confined to a levee-lined course as it flows to the northeast across the North China Plain before emptying into the Bohai Sea. The basin area in this stage is only , a mere 3% of the total, because few tributaries add to the flow in this stage; nearly all rivers to the south drain into the Huai River, whereas those to the north drain into the Hai River. The Huai River Basin, for example, is separated from the Yellow River Basin by the south dike of the Yellow River. The total drop in elevation of the lower reaches is , with an average grade of 0.012%.


title: Yellow River

text: The silts received from the middle reaches form sediments here, elevating the river bed. Excessive sediment deposits have raised the riverbed several meters above the surrounding ground. At Kaifeng, Henan, the Yellow River is above the ground level.


title: Yellow River

text: The Yellow River is notable for the large amount of silt it carries—1.6 billion tons annually at the point where it descends from the Loess Plateau. If it is running to the sea with sufficient volume, 1.4 billion tons are carried to the sea per year. One estimate gives 34 kilograms of silt per cubic meter as opposed to 10 for the Colorado and 1 for the Nile.


title: Yellow River

text: Its average discharge is said to be 2,110 cubic meters per second (32,000 for the Yangtze), with a maximum of 25,000 and minimum of 245. However, since 1972, it often runs dry before it reaches the sea. The low volume is due to increased agricultural irrigation, increased by a factor of five since 1950. Water diverted from the river as of 1999 served 140 million people and irrigated 74,000 km (48,572 mi) of land. The Yellow River delta totals 8,000 square kilometers (3,090 mi). However, with the decrease in silt reaching the sea, it has been reported to be shrinking slightly each year since 1996 through erosion.


title: Yellow River

text: The highest volume occurs during the rainy season from July to October, when 60% of the annual volume of the river flows. Maximum demand for irrigation is needed between March and June. In order to capture excess water for use when needed and for flood control and electricity generation, several dams have been built, but their expected life is limited due to the high silt load. A proposed South–North Water Transfer Project involves several schemes to divert water from the Yangtze River: one in the western headwaters of the rivers where they are closest to one another, another from the upper reaches of the Han River, and a third using the route of the old Grand Canal.


title: Yellow River

text: Due to its heavy load of silt the Yellow River is a depositing streamthat is, it deposits part of its carried burden of soil in its bed in stretches where it is flowing slowly. These deposits elevate the riverbed which flows between natural levees in its lower reaches. Should a flood occur, the river may break out of the levees into the surrounding lower flood plain and take


title: Yellow River

text: a new channel. Historically this has occurred about once every hundred years. In modern times, considerable effort has been made to strengthen levees and control floods.


title: Yellow River

text: Below is the list of hydroelectric power stations built on the Yellow River, arranged according to the first year of operation (in brackets):


title: Yellow River

text: As reported in 2000, the 7 largest hydro power plants (Longyangxia, Lijiaxia, Liujiaxia, Yanguoxia, Bapanxia, Daxia and Qinglongxia) had the total installed capacity of 5,618 MW.


title: Yellow River

text: The Yellow River basin is rich in fish, being the home of more than 160 native species in 92 genera and 28 families, including 19 species found nowhere else in the world (endemic). However, due to habitat loss, pollution, introduced species and overfishing many of the natives have declined or disappeared entirely; several are recognized as threatened on China's Red List. Dams and their reservoirs have increased the habitat for species of slow-moving and static waters, while it excluded species of flowing waters and prevented the up- and down-stream breeding migration of others. In the 2000s, only 80 native fish in 63 genera and 18 families were recorded in the Yellow River basin. In contrast, introduced fish have risen in both abundance and number of species; only one introduced fish species was recorded in the 1960s when ichthyologist Li Sizhong published his original survey of fish fauna of the region, but by the 2000s there were 26.


title: Yellow River

text: As typical of Asian rivers, Cyprinidae is by far the most diverse family in the Yellow River basin. More than 85 cyprinids have been recorded in this basin, including species that still are present and species that no longer are present. Other highly diverse families are the stone loaches (more than 20 species), gobies ( 15 species), true loaches ( 10 species) and bagrid catfish ( 10 species). Although there are species found throughout much of the river, several have a more restricted range. For example, the uppermost, highest parts on the Qinghai–Tibet Plateau has relatively few native species, notably snowtrout and allies ("Gymnocypris", "Gymnodiptychus", "Platypharodon" and "Schizopygopsis"), and "Triplophysa" loaches. Of the 18 endemics in the Yellow River basin, 12 are (or were) found in the upper part. These in particular have become threatened and the fish fauna in many headwaters are now dominated by introduced salmonids. In contrast, the lowermost part of the river and its delta are home to many brackish water or euryhaline species, like gobies (although there are also true freshwater gobies in the Yellow River), Asian seabasses, flatfish and "Takifugu" pufferfish.


title: Yellow River

text: Fishing remains an important activity, but catches have declined. In 2007, it was noted that 40% fewer fish were caught in the Yellow River compared to earlier catches. Large cyprinids (Asian carp, predatory carp, Wuchang bream and Mongolian redfin) and large catfish (Amur and Lanzhou catfish) are still present, but the largest species, the Chinese paddlefish, kaluga sturgeon and Yangtze sturgeon, have not been reported from the Yellow River basin in about 50 years. Other species that support important fisheries include white Amur bream, ayu, mandarin fish, "Protosalanx" icefish, northern snakehead, Asian swamp eel and others.


title: Yellow River

text: Annual fishing ban has been implemented since 2018, covering the entire Yellow River basin from April 1 to June 30 each year. A total ban of fishing of natural fishes is being implemented in the upper reaches of the Yellow River starting April 1, 2022, covering Qinghai, Sichuan and Gansu provinces, until the end of 2025. For the rest of the basin, the annual ban is extended to a period from April 1 to July 31.


title: Yellow River

text: The Yellow River is generally less suitable for aquaculture than the rivers of central and southern China, such as the Yangtze or the Pearl River, but aquaculture is also practiced in some areas along the Yellow River. An important aquaculture area is the riverside plain in Xingyang City, upstream from Zhengzhou. Since the development of fish ponds started in Xingyang's riverside Wangcun Town in 1986, the pond systems in Wangcun have grown to the total size of 15,000 "mu" (10 km), making the town the largest aquaculture center in North China.


title: Yellow River

text: Two turtle species are native to the Yellow River basin: the Chinese pond turtle and Chinese softshell turtle. Both species—but especially the softshell—are widely farmed for food. A variety of the Chinese softshell turtle popular in Chinese gourmets is called the Yellow River turtle (). Nowadays most of the Yellow River turtles eaten in China's restaurants comes from turtle farms, which may or may not be near the Yellow River.


title: Yellow River

text: In 2007, construction started in Wangcun, Henan on a large farm for raising this turtle variety. With the capacity for raising 5 million turtles a year, the facility was expected to become Henan's largest farm of this kind.


title: Yellow River

text: The huge, entirely aquatic Chinese giant salamander, a species that has declined drastically due primarily to persecution for food and traditional medicine, is native to the Yellow River and other Chinese rivers. It is farmed in large numbers in several parts of China and genetic studies have revealed that the captive stock mostly is of Yellow River origin. As these often are released back into the wild, the Yellow River type of the Chinese giant salamander has spread to other parts of China, which represents a problem to the other types.


title: Yellow River

text: On 25 November 2008, Tania Branigan of "The Guardian" filed a report "China's Mother River: the Yellow River", claiming that severe pollution has made one-third of China's Yellow River unusable even for agricultural or industrial use, due to factory discharges and sewage from fast-expanding cities. The Yellow River Conservancy Commission had surveyed more than of the river in 2007 and said 33.8% of the river system registered worse than "level five" according to the criteria used by the UN Environment Program. Level five is unfit for drinking, aquaculture, industrial use, or even agriculture. The report said waste and sewage discharged into the system last year totaled 4.29b tons. Industry and manufacturing made up 70% of the discharge into the river with households accounting for 23% and just over 6% coming from other sources.


title: Yellow River

text: In ancient times, it was believed that the Yellow River flowed from Heaven as a continuation of the Milky Way. In a Chinese legend, Zhang Qian is said to have been commissioned to find the source of the Yellow River. After sailing up-river for many days, he saw a girl spinning and a cow herd. Upon asking the girl where he was, she presented him with her shuttle with instructions to show it to the astrologer Yan Junping (嚴君平). When he returned, the astrologer recognized it as the shuttle of the Weaving Girl (Vega), and, moreover, said that at the time Zhang received the shuttle, he had seen a wandering star interpose itself between the Weaving Girl and the cow herd (Altair).


title: Yellow River

text: The provinces of Hebei and Henan derive their names from the Yellow River. Their names mean, respectively, "North of the River" and "South of the River", although the border between them historically has never been stable, and currently the border between Hebei and Henan is not the Yellow River, but the Zhang River instead.


title: Yellow River

text: Traditionally, it is believed that the Chinese civilization originated in the Yellow River basin. The Chinese refer to the river as "the Mother River" and "the cradle of the Chinese civilization".


title: Yellow River

text: During the long history of China, the Yellow River has been considered a blessing as well as a curse and has been nicknamed both "China's Pride" and "China's Sorrow".


title: Yellow River

text: Despite Yellow River having a central role in the development of Chinese civilization on North China Plain, flooding and constant rerouting of the river have also caused many great disaster to population along the river for long, hence it is also known as a River of disaster (), with the disaster brought by the River said as history of disaster in the development of Chinese civilization, and the management of Yellow River have been a great political trouble to various Chinese dynasties throughout the history since ancient time.


title: Yellow River

text: Sometimes the Yellow River is poetically called the "Muddy Flow" (). The Chinese idiom "when the Yellow River flows clear" is used to refer to an event that will never happen and is similar to the English expression "when pigs fly".


title: Yellow River

text: "The Yellow River running clear" was reported as a good omen during the reign of the Yongle Emperor, along with the appearance of such auspicious legendary beasts as "qilin" (an African giraffe brought to China by a Bengal embassy aboard Zheng He's ships in 1414) and "zouyu" (not positively identified) and other strange natural phenomena.


title: Stay (The Kid Laroi and Justin Bieber song)

text: "Stay" is a song by Australian rapper and singer the Kid Laroi and Canadian singer Justin Bieber. It was released through Grade A Productions and Columbia Records on 9 July 2021, as the lead single (sixth overall) from Laroi's reloaded mixtape, "F*ck Love 3: Over You". Laroi and Bieber wrote the song with Haan, FnZ members Finatik & Zac, and producers Cashmere Cat, Charlie Puth, Omer Fedi, and Blake Slatkin. The song marks the second collaboration between the two artists, following Bieber's song, "Unstable", a track from his sixth studio album, "Justice".


text: "Stay" peaked at number one on the "Billboard" Hot 100, becoming Laroi's first chart-topping song and Bieber's eighth. The song additionally topped the "Billboard" Global 200. Furthermore, it reached number one in 22 other countries, including their respective natives Australia and Canada, along with Germany, India, the Netherlands, New Zealand, Norway, South Korea, and Sweden. It also peaked within the top ten in 18 other countries. It is the fastest song to reach the milestone of two billion streams on Spotify. At the 2021 ARIA Music Awards, the song won the ARIA Award for Best Pop Release, which resulted in Laroi and Bieber both winning the ARIA Award for Best Artist. At the APRA Music Awards of 2022, the song won the award for Song of the Year.


text: On 20 September 2020, Laroi shared a snippet of the song on an Instagram live stream, followed by a longer snippet in better quality that was previewed on a live stream from Rolling Loud on 29 October 2020. Bieber's contribution to the song was revealed on 31 May 2021. The song leaked in full on a Discord server on 2 June 2021.


text: "Stay" marks Laroi's first major single release as a lead artist in 2021 and Bieber's first major single as a lead artist since the release of his second extended play, "Freedom", which was released in April 2021. On 3 June 2021, Scooter Braun, who has been Bieber's manager from the start of his career, also became Laroi's manager, until Laroi left and joined Adam Leber at Rebel Management on 27 September 2021.


text: Laroi had the song for about a year before its release. He created the song while spending time with producers Charlie Puth, Omer Fedi, and Blake Slatkin at Slatkin's house. Puth played the melody of the song on the keyboard, but Laroi ended up liking it and wanted to get it in production software Pro Tools to use it to create a song. He felt that "it was probably the most organic way of making a song I've ever done – ever". Laroi thought Bieber "would sound perfect", so he went to the studio at which Bieber records; they finished recording the song, but Bieber was hesitant about whether his vocals sounded good or not.


text: "Stay" is a fast-paced pop rap, pop rock, and synth-pop song. It is set in the key of D major and incorporates piano keys, heavy drums, and "splattering" synths. The upward-darting keyboard riff, made on a Roland Juno-60 synthesizer owned by producer Blake Slatkin, serves as the song's spine and eventually becomes the chorus melody. Over a repeated melodic cell, Laroi and Bieber switch between head voice and chest voice on a minor sixth. Jon Caramanica of "The New York Times" described the track as a "hyper-slick" hybridization of new wave and pop-punk. Some critics found similarities between it and the music from Bieber's sixth studio album, "Justice" (2021). Justin Curto from "Vulture" compared the song's sound to "Justice" single "Hold On" and album tracks "Die for You" and "Somebody". "Stereogum"s Chris DeVille characterised it as SoundCloud pop-rap as effervescent "Justice"-style '80s pop".


text: The "heartbreak-fueled" lyrics to "Stay" enforce Laroi's toxic behaviour as he sets up a story about a troubled relationship where he is at fault. In the chorus, he sings about his broken promises before begging for his partner to stay with him: "I do the same thing I told you that I never would / I told you I'd change, even when I knew I never could." Robert Rowat of CBC Music interpreted the lines as "an admission of weakness, if not a promise to be better". Bieber's verse echoes similar sentiments as he belts out lyrics about being unable to live without his loved one: "When I'm away from you, I miss your touch / You're the reason I believe in love." The song reaches its climax as Laroi and Bieber's voices join in the last chorus.


text: On 16 June 2021, Laroi and Bieber hinted at another collaboration. Leading up to its release, the two artists both teased the song multiple times on their respective social media accounts by posting snippets and teasing the lyrics. Laroi also had previously stated on social media that Ron Perry, the label boss of Columbia Records would not release the song, to which Laroi asked his fans to repeatedly spam Ron Perry on Instagram, which would hopefully change his mind into releasing it. Laroi posted a picture of him at a basketball game on Instagram on 27 June 2021, holding a piece of paper that wrote the song title and the then-questionable release date, to which American singer-songwriter Charlie Puth, who is one of the producers of the song, teased his involvement of the song by commenting "Yessssssssss". Three days later, Laroi shared a pre-order link in order to reveal the cover art, which would be posted the following day.


text: The song has received generally positive reviews. Writing for "The New York Times", Jon Caramanica found "Stay" to be effective", considering it a more effective pairing of Laroi and Bieber than their previous collaboration on "Unstable" from the latter's sixth studio album, "Justice". Tyler Jenke from "Rolling Stone Australia" wrote that "the slick new tune" is "undoubtedly one that lives up [to] the hype". Jordan Rose of "Complex" believed that the track has Laroi and Bieber "leaning into their strengths". Alex Zidel from "HotNewHipHop" felt that the song is "every bit as infectious as [one] would expect" and thought of it to be "a solid pop offering for the summer". Jason Lipshutz of "Billboard" opined that the song "sounds like it should push [Laroi] to a new level" of stardom. "Uproxx" contributing writer Carolyn Droke stated that the "buoyant track['s]" combination of "a euphoric chorus and a driving beat" will make it "the next song of the summer". Robert Rowat of CBC Music commended Laroi and Bieber's partnership as "one of the year's best surprises" and said that the song "capitalizes on both singers' skills as falsettists". Chris DeVille from "Stereogum" described the song as "maniacally catchy" and thought it musically feels like Laroi "blasting off into a new frontier of crossover success". "Vulture"s Justin Curto called the track "a high-energy, synth-filled pop banger". However, he later criticised the song for being "some of Laroi's most anonymous work yet" and concluded that "it could just as easily be a hit for the Weeknd or Post Malone".


text: "Stay" debuted at number one on the ARIA Singles Chart for the week of 19 July 2021. It became Laroi's second number-one single in Australia after "Without You" topped the chart for a week in May and Bieber's fifth as a lead artist. It held on to its position for 14 consecutive weeks, becoming the longest-running number-one single of 2021. In January 2022, the song returned to the number one spot following the 2021 Triple J Hottest 100's announcement and remained there for three additional weeks. Its 17-week reign became the longest run at the top of the ARIA Singles Chart by a male artist(s) and the second-longest overall.


text: In New Zealand, "Stay" entered at the top of the New Zealand Singles Chart, securing Laroi's first number-one single in the country and Bieber's 11th overall. The song spent more weeks at number one than any other by an Australian male, maintaining that position for 11 non-consecutive weeks.


text: In the United Kingdom, "Stay" entered at number five on the UK Singles Chart on 16 July 2021 – for the week ending dated 22 July 2021 – making it Laroi's second top ten hit in Britain and Bieber's 27th. It rose three places to number two a week later, behind Ed Sheeran's "Bad Habits" during its fourth week at the summit. It stayed at number two for six weeks and became Laroi's joint-highest-charting song in the UK along with "Without You".


text: In Ireland, "Stay" entered at number three on the Irish Singles Chart as the week's highest new entry. The track became Bieber's 60th top 50 single in the Irish Republic. The song moved up a spot the following week to a new peak of number two behind "Bad Habits" for eight weeks, becoming Laroi's highest-charting song in Ireland.


text: In the United States, "Stay" debuted at number three on the "Billboard" Hot 100, starting with 34.7 million streams, 12.9 million in radio audience, and 12,000 in sales. It entered atop the Streaming Songs chart, becoming Laroi's first and Bieber's sixth leader there, and at number five on the Digital Song Sales chart. Laroi earned his third top 10 hit on the Hot 100 and a new career best, surpassing the number eight peak of "Without You" with Miley Cyrus. In addition to Bieber getting his 24th top 10 hit on the chart, he became the youngest artist to have 100 entries appear on the Hot 100 at 27 years and four months old. On the week of 14 August 2021, the song topped the "Billboard" Hot 100, dethroning BTS' "Butter" and becoming Laroi's first and Bieber's eighth number-one hit on the chart. It stayed at the number-one position for four consecutive weeks, surpassing "Sorry" as Bieber's longest reign as a lead artist. The song also became Laroi's first number one on the Pop Airplay chart (where it went on to spend 13 weeks at #1, the second longest run at #1 in the history of the chart, behind Ace of Base's "The Sign"), while Bieber tied Bruno Mars for the most number ones on the chart among solo males with nine each. On the week of 25 September 2021, "Stay" returned to number one on the Hot 100 for a fifth week as it topped the Radio Songs chart for the first time, becoming the first and fifth leader for Laroi and Bieber, respectively. The song spent seven non-consecutive weeks at number one on the Hot 100. It additionally logged a record 14 non-consecutive weeks at number two of the Hot 100. As of the chart dated 2 April 2022, "Stay" also broke the records for the most weeks spent in the Hot 100's top two and top three spots, with 21 and 23 weeks respectively. The record has since been surpassed by Harry Styles' "As It Was" with 25 and 29 weeks, respectively in 2022. On 18 April 2022, "Stay" became the first song in history to spend its first 40 weeks consecutively in the top 10 of the Hot 100.


text: On the "Rolling Stone" Top 100, the song earned Laroi his first number one with 30.8 million streams on opening week. It spent seven straight weeks at number one on the chart, becoming just the third song to do so after Roddy Ricch's "The Box" and Rodrigo's "Good 4 U". The track was named "2021's Song of the Summer" by "Variety" based on a song project report from Alpha Data, where it earned 1.5 million units. As of 28 October 2021, the song has accumulated 1.1 billion in airplay audience and 537.6 million U.S. streams and has sold 177,200 downloads.


text: "Stay" additionally topped the charts in Austria, both regions of Belgium (Flanders and Wallonia), Bieber's native Canada, the Czech Republic, Denmark, Finland, Germany, Iceland, India, Israel, Malaysia, the Netherlands, Norway, Singapore, Slovakia, South Korea, and Sweden, and peaked within the top 10 in France, Italy, Japan, Portugal, and Switzerland. Worldwide, the song debuted at number two on the "Billboard" Global 200 behind BTS's "Permission to Dance". It opened with 76.3 million streams and 18,600 sold. The song ascended to number one on its third week with 75.1 million streams and 13,900 in sales, making it Laroi's first leader on the chart and Bieber's second after "Peaches". It later topped the "Billboard" Global Excl. U.S. on the chart dated 21 August 2021, dethroning "Bad Habits". The song was the longest-reigning number one on the Global 200, at the time and the first to lead it for double-digits, spending a total of eleven weeks at the top of the chart. On 4 November 2021, the song reportedly reached one billion streams on Spotify, becoming the fastest to do so in 118 days and surpassing the previous record held by Sheeran with "Shape of You" in 153 days. On 6 August 2022, 392 days after its release, the song became the fastest to hit two billion streams on Spotify, surpassing previous record holder, The Weeknd's Blinding Lights. "Stay" was the most-streamed song globally on Apple Music in 2022.


text: The official music video for "Stay", directed by Colin Tilley, premiered alongside the song's release at midnight on 9 July 2021. It depicts Laroi and Bieber dancing in a city where time has stopped flowing and all other people are frozen still. Elisa Talbot served as the video's cinematographer while Jack Winter produced it, with Jamee Ranta and Tilley as executive producers. The music video has more than 600 million views on YouTube as of 11 August 2022.


text: "Stay" received its first live performance on 9 July 2021, the same day as its release, where Laroi joined Bieber during his set at the Encore Theater at the Wynn in Las Vegas. A live performance video of the song from the show was uploaded on Laroi's YouTube channel on 12 July. The two performed it on 10 July at the grand opening of the hotel's new supper club, Delilah, towards the end of Bieber's eight-song set. On 5 September, Bieber also brought Laroi out to perform "Stay" during his set of the Made In America Festival in Philadelphia, Pennsylvania, in which he was one of the headliners of alongside American rapper Lil Baby. Exactly one week later, Bieber invited Laroi to perform the song at the 2021 MTV Video Music Awards from the Barclays Center in Brooklyn, New York, for his two-song set that also included his performance of his single, "Ghost". Laroi appeared on a dimly lit stage to perform a stripped-back version of the song during "Jimmy Kimmel Live!" on 29 October, where he was accompanied by a pianist. On 24 November, Laroi closed out the 2021 ARIA Music Awards with a punk-inspired rendition of the song backed by a full band in front of a small club audience. On 11 December, Bieber gave his first solo performance of the song during the Capital FM's Jingle Ball festival at the O2 Arena in London, England, in which he sang his verse of the song and a portion of the chorus before it without the song playing at all.


title: Ready Player One

text: Ready Player One is a 2011 science fiction novel, and the debut novel of American author Ernest Cline. The story, set in a dystopia in 2045, follows protagonist Wade Watts on his search for an Easter egg in a worldwide virtual reality game, the discovery of which would lead him to inherit the game creator's fortune. Cline sold the rights to publish the novel in June 2010, in a bidding war to the Crown Publishing Group (a division of Random House). The book was published on August 16, 2011. An audiobook was released the same day; it was narrated by Wil Wheaton, who was mentioned briefly in one of the chapters. In 2012, the book received an Alex Award from the Young Adult Library Services Association division of the American Library Association and won the 2011 Prometheus Award.


title: Ready Player One

text: A film adaptation, screenwritten by Cline and Zak Penn and directed by Steven Spielberg, was released on March 29, 2018. A sequel novel, "Ready Player Two", was released on November 24, 2020, to a widely negative critical reception.


title: Ready Player One

text: In the 2040s, the world has been gripped by an energy crisis from the depletion of fossil fuels and the consequences of pollution, global warming and overpopulation, causing widespread social problems, poverty, and economic stagnation. To escape the decline their world is facing, people turn to the OASIS, a virtual reality simulator accessible by players using visors and haptic technology such as gloves. It functions both as an MMORPG and as a virtual world, with its currency being the most stable in the real world. It was created by James Donovan Halliday, founder of Gregarious Simulation Systems (formerly Gregarious Games), who made a posthumous video of his will stating to the public that he had left an Easter egg inside the OASIS, and the first person to find it would inherit his entire fortune, ownership of his corporation as well as complete control of the OASIS itself, which is worth trillions. The story follows the adventures of Wade Watts, starting about five years after the announcement, when he discovers one of the three keys which unlock three successive gates leading to the treasure.


title: Ready Player One

text: Teenager Wade Watts lives with his aunt in Oklahoma City in the "stacks", a poverty-stricken district constructed of trailer homes piled on top of each other. He spends his spare time as a "gunter" ("egg hunter"), logging on to the OASIS as an avatar under the moniker Parzival, reading Halliday's journal "Anorak's Almanac", and researching details of the 1980s pop culture, mainly classic video games and movies, that Halliday loved. One day, he realizes that the first key is located on Ludus, the same virtual world as his own online high school, in a re-creation of the "Dungeons & Dragons" module "Tomb of Horrors". He meets Art3mis, a famous female gunter and blogger, and advances further than she does when he defeats the AI Acererak at the video game "Joust". He is awarded the Copper Key, and appears on the "Scoreboard", attracting the world's attention.


title: Ready Player One

text: Parzival completes the Copper Gate's puzzles on the planet Middletown, which is modeled after Halliday's boyhood home. He plays through the "Dungeons of Daggorath" video game in a recreation of Halliday's parents' house and then role-playing Matthew Broderick's character in the film "WarGames". Art3mis clears the gate shortly afterwards, as does Wade's best friend Aech. Wade's fame enables him to make a living by endorsing virtual products. It also brings him to the attention of Nolan Sorrento, head of operations at Innovative Online Industries (IOI), a multinational corporation bent on a well-funded effort to find the Easter egg in order to take control of the OASIS and monetize it. When Wade refuses to join IOI, Sorrento attempts to kill him by blowing up the stacks where Wade lives, killing his aunt and disguising the explosion as a meth lab accident.


title: Ready Player One

text: Wade escapes and moves to Columbus, Ohio (hometown of both GSS and IOI), where he assumes the pseudonym Bryce Lynch and living in an anonymous apartment designed for hardcore OASIS users. He begins a wary friendship with Art3mis, but when he asks her out, she declines.


title: Ready Player One

text: After Five months pass, Art3mis finally finds the Jade Key, and Parzival believes it to be on Archaide, a planet containing a copy of every video game ever made, where he plays a perfect game of "Pac-Man", thinking it part of the Egg hunt, but receives only a quarter as a prize. Aech, after finding the Jade Key, provides a hint leading him to the planet Frobozz where he solves a recreation of the text adventure game "Zork" and whistles a 2600-hertz-sound through a Cap'n Crunch Bo'Sun whistle. Sorrento establishes a base there to farm Jade Keys for their company's avatars, unlocks the second Gate, and rapidly acquires the Crystal Key as well through trial and error. Shoto, another high ranking Gunter tells Parzival that Sixers have killed his partner Daito, passing it off as a Japanese suicide.


title: Ready Player One

text: Parzival unlocks the Jade Gate, a Voight-Kampff machine, by entering a privately-owned "Blade Runner"-themed building, and completes the arcade game "Black Tiger" and is awarded a virtual mecha as the prize and another clue: a red star in a circle. He acquires the Crystal Key on planet Syrinx, and after playing the track "Discovery", finds a clue regarding the conditions to unlock the final gate. As he messages Art3mis, Aech, and Shoto with instructions on how to get through the Jade Gate and obtain the Crystal Key, Sorrento ends his covert attempts to clear the third gate, located in the fortress of Halliday's avatar, Castle Anorak, on planet Chthonia, and places an indestructible force field around it.


title: Ready Player One

text: Wade manipulates his assumed identity in order to be arrested and placed in indentured servitude in IOI's tech support department. He then uses black market passwords and security exploits to hack into IOI's intranet and acquires a wealth of incriminating information: footage of Daito's murder, the attempt on his own life, as well as plans to abduct Shoto and Art3mis and force them to find the Easter egg for IOI, then kill them afterwards. Aech remains anonymous due to his mobile setup. After escaping the corporation, he shares his information with his friends and publicizes a gathering of avatars to storm the castle. They are interrupted by Ogden Morrow, who offers them a safe haven at his home in Oregon. Wade meets the real-life Aech and Ogden, but not Art3mis or Shoto, who are already hooked into Ogden's immersion pods.


title: Ready Player One

text: The day of the battle, Wade uses a previously deployed booby trap to bring down the barricade, and a massive fight among avatars ensues. Parzival, Art3mis, Aech and Shoto use their Mechas to fight Sorrento's "Mechagodzilla" Kiryu, though Parzival has to use his Ultraman artifact to defeat and kill Sorrento's mecha and avatar. IOI use a doomsday device artifact called the Cataclyst to destroy the castle and all avatars in the entire sector. Parzival survives because having the "Pac-Man" quarter granted him an extra life. As he enters the Crystal Gate, he announces that if he wins the final challenge, he will share his fortune with the three of his friends. He plays "Tempest," role-plays King Arthur and various other characters in "Monty Python and the Holy Grail", and retrieves the Easter egg in "Adventure". His victory grants him control of the OASIS. Sorrento is arrested for the murder of Daito and conspiring to kill Wade and the others. Back in Oregon, Wade and Art3mis, whose actual name is Samantha, meet in person and rekindle their relationship with a kiss.


title: Ready Player One

text: "Ready Player One" was a "New York Times" bestseller. Among those praising the book were "Entertainment Weekly", "The Boston Globe", "The A.V. Club", CNN.com, io9, and "Boing Boing". "USA Today" wrote that the novel "undoubtedly qualifies Cline as the hottest geek on the planet right now." NPR said that the book was "ridiculously fun and large-hearted". Cline "takes a far-out premise and engages the reader instantly" with a "deeply felt narrative [that] makes it almost impossible to stop turning the pages." Janet Maslin of "The New York Times" wrote that "The book gets off to a witty start" but noted that it lacks at least one dimension, stating that gaming had overwhelmed everything else about this book. Rebecca Serle of "HuffPost" described the book as "the grown-up's "Harry Potter"" and that it "has it all – nostalgia, trivia, adventure, romance, heart and, dare I say it, some very fascinating social commentary." The book has been translated into over 20 languages.


title: Ready Player One

text: Discussion on the book was renewed in the months leading up to the release of Steven Spielberg’s film adaptation. In contrast to the book’s contemporary reviews, which were generally positive, these were substantially more negative and triggered a social media backlash towards the book and the then upcoming film adaptation. Nick Shager, writing for "The Daily Beast", offered a scathing review that criticized the book's narrative style by stating "It’s... a terribly written piece of adolescent fantasy that, at heart, exemplifies everything wrong and repellent about modern nerd culture" and challenged its coming-of-age premise by calling it "a stunted-adolescent story". Regarding the abundance of pop culture references, Shager called the book "an unbearable celebration of nostalgic juvenilia". He summarized his argument against the book by stating "It’s a lionization of immature things (and immaturity) as an end to itself, rather than as the building blocks of more mature – and worthwhile – creations". Shager also lamented the book's "Peter Pan-ish infatuation with childishness, which comes coated in a stench of stale Doritos, Jolt Cola and lowbrow smugness".


title: Ready Player One

text: Michael J. Nelson's and Conor Lastowka's podcast series "372 Pages We'll Never Get Back" dissected the book, criticizing it for defective worldbuilding, repetitive and excessive pop culture references in place of descriptive writing, and weak plot.


title: Ready Player One

text: In 2018, the book garnered negative reception from critics who believed it pandered too much on the male demographic, which other online publications later disputed. Writer Chris Isaac of "Tor" disagreed with the criticisms, stating "So, if you don’t like Ready Player One and have criticisms about it, that’s totally understandable" while adding "I’ll certainly point out the issues I have with his stories, but I’m not going to delight in mocking his work or hoping for his failure like many did with Meyer and "Twilight"." Constance Grady of "Vox" described in an article about how Gamergate have changed the perception of the book over time: "For readers in Cline’s target demographic in 2011, that message felt empowering. For readers who weren’t, it felt like a harmless piece of affirmation meant for someone else. Everyone deserves a silly escapist fantasy, right?" to "But in this world [...] only things that affect straight white dudes really matter".


title: Ready Player One

text: "Lacero", a fan-fiction short story by Andy Weir, was published online in 2014, and later included in the 2016 limited edition of "Ready Player One" published by Subterranean Press.


title: Ready Player One

text: It functions as a precursor to the main novel, and is considered canonical to the "Ready Player One" fictional universe.


title: Ready Player One

text: As early as 2015, Cline had been reported to be working on a sequel to "Ready Player One" from screenwriter Zak Penn. Cline confirmed the sequel was in progress by December 2017, and would have a different story-line involving all of the characters, while still exploring pop culture references like the first book. Penguin House released the sequel, "Ready Player Two" on November 24, 2020. The plot follows Wade as he embarks on a new quest after discovering a new technology developed by Halliday. Between the weeks of November 29 and December 20 of 2020, it was number one on Amazon's fiction chart.


title: Ready Player One

text: Ten months after the first edition's release, Cline revealed on his blog that "Ready Player One" itself contained an elaborately hidden Easter egg. This clue would form the first part of a series of staged video gaming tests, similar to the plot of the novel. Cline also revealed that the competition's grand prize would be a DeLorean. The Easter egg was a URL hidden in the book for anoraksalmanac.com. This was the first stage of the contest where the 2011 Atari 2600 game "The Stacks" by developers Mike Mika & Kevin Wilson was featured. The game "Ultimate Collector: Garage Sale" by Austin-based developer Portalarium was featured in the second stage of the contest. The final stage of the contest was announced on August 1, 2012, and was to set a world record on one of several classic arcade or Atari 2600 games. This was completed on August 9, 2012 by Craig Queen, who set a new world record in "Joust". He was awarded the DeLorean on the TV series "X-Play".


title: Ready Player One

text: The film rights were purchased by Warner Bros. on the same day Cline finalized his publishing deal with Random House, one year prior to the novel's publication. Dan Farah brought the project into the studio and produced it with Donald De Line. Cline adapted his novel into a screenplay. Over the years, Eric Eason and Zak Penn assisted Cline with rewrites.


title: Ready Player One

text: Steven Spielberg signed on to direct in March 2015. Spielberg and Kristie Macosko Krieger of Amblin Partners also joined Deline and Farah as producers. Warner Bros. initially announced a release date of December 15, 2017. On February 9, 2016, the release date was pushed back to March 30, 2018, to avoid competition with "". The movie began production in the spring of 2016 and was filmed in both the United States and the United Kingdom.


title: Ready Player One

text: On June 9, 2016, "Variety" stated that Spielberg's regular collaborator John Williams was planning on composing the film's score. However, scheduling conflicts with another Spielberg film, "The Post", led to Spielberg signing Alan Silvestri for the score.


title: Ready Player One

text: The film stars Tye Sheridan, Olivia Cooke, Ben Mendelsohn, Lena Waithe, T. J. Miller, Simon Pegg, and Mark Rylance with Philip Zao, Win Morisaki, and Hannah John-Kamen in supporting roles. It premiered at South by Southwest on March 11, 2018, and was theatrically released by Warner Bros. in the United States on March 29, 2018. It received generally positive reviews from critics who praised its visuals and brisk pacing, the performances of Sheridan and Rylance, and noted it as an improvement on the book. The film nonetheless received criticism for its lack of character development and its "achingly regressive" view of pop culture fans.


title: Beechcraft T-6 Texan II

text: The Beechcraft T-6 Texan II is a single-engine turboprop aircraft built by the Raytheon Aircraft Company (Textron Aviation since 2014). A trainer aircraft based on the Pilatus PC-9, the T-6 has replaced the United States Air Force's Cessna T-37B Tweet and the United States Navy's T-34C Turbo Mentor.


title: Beechcraft T-6 Texan II

text: The T-6A is used by the United States Air Force for basic pilot training and Combat Systems Officer (CSO) training, the United States Navy and United States Marine Corps for primary Naval Aviator training and primary and intermediate Naval Flight Officer (NFO) training, and by the Royal Canadian Air Force (CT-156 Harvard II designation), Greek Air Force, Israeli Air Force (with the "Efroni" nickname), and Iraqi Air Force for basic flight training. The T-6B is the primary trainer for U.S. student naval aviators (SNAs). The T-6C is used for training by the Mexican Air Force, Royal Air Force, Royal Moroccan Air Force, and the Royal New Zealand Air Force.


title: Beechcraft T-6 Texan II

text: The Model 3000/T-6 is a low-wing cantilever monoplane with enclosed tandem seating for two. It is powered by single Pratt & Whitney Canada PT6A-68 turboprop engine in tractor configuration with an aluminum, , four-blade, constant-speed, variable pitch, non-reversing, feathering propeller assembly and has retractable tricycle landing gear. The aircraft is fitted with Martin-Baker Mark 16 ejection seats and a canopy fracturing system.


title: Beechcraft T-6 Texan II

text: The T-6 is a development of the Pilatus PC-9, modified by Beechcraft to enter the Joint Primary Aircraft Training System (JPATS) competition in the 1990s. A similar arrangement between Pilatus and British Aerospace had also been in place for a Royal Air Force competition in the 1980s, although that competition selected the Short Tucano. The aircraft was designated under the 1962 United States Tri-Service aircraft designation system and named for the decades-earlier T-6 Texan.


title: Beechcraft T-6 Texan II

text: The JPATS competition-winning design was based on a commercial off-the-shelf Pilatus PC-9, with minor modifications. Additional requirements and conflicts between the Air Force and the Navy resulted in delays, cost increases (from initial estimates of $3.9 to roughly $6 million per aircraft) and an aircraft that is 22% or heavier than the Pilatus.


title: Beechcraft T-6 Texan II

text: On 9 April 2007, the U.S. Department of Defense released their Selected Acquisition Reports, which reported that the T-6 JPATS program was one of only eight programs cited for Congressional notification for 25–50% cost overrun over initial estimates, which is referred to as a "Nunn-McCurdy Breach" after the Nunn-McCurdy Amendment. It is unusual for a program so far into full-rate production to experience significant enough cost overruns to trigger this congressional notification.


title: Beechcraft T-6 Texan II

text: The T-6A was introduced to Moody Air Force Base and Randolph Air Force Base in 2000–2001, and the Air Force awarded the full-rate T-6 production contract in December 2001. Laughlin Air Force Base began flying the T-6 in 2003 where it became the primary basic trainer, replacing the T-37. Vance Air Force Base completed transitioning from the T-37 to the T-6 in 2006. That year, Columbus Air Force Base began its transition, and retired its last T-37 in April 2008. The last active USAF T-37Bs were retired at Sheppard Air Force Base in the summer of 2009.


title: Beechcraft T-6 Texan II

text: The Texan failed to qualify for the Light Attack/Armed Reconnaissance program, because the USAF mailed the exclusion notice to the wrong address, leaving the company with no time to protest the decision. But the official mail failure gave Hawker-Beechcraft a further legal justification, as they had told the USAF they planned to file a legal challenge even before the official notice had been mailed and brought its considerable political influence to bear against the USAF decision against their candidate with one Kansas Congressman stating, "It is simply wrong for the Obama administration to hire a Brazilian company to handle national security when we have a qualified and competent American company that can do the job." In 2013, Beechcraft was once again the loser.


title: Beechcraft T-6 Texan II

text: In August 2017, the Air Force conducted the "Light Attack Experiment" to evaluate potential light attack aircraft. Following this, it decided to continue experimenting with two non-developmental aircraft, the AT-6 Wolverine derivative of the T-6 Texan II and the Sierra Nevada/Embraer A-29 Super Tucano. Tests were scheduled to be conducted at Davis-Monthan Air Force Base, Arizona between May and July 2018. The tests are intended "to experiment with maintenance, data networking and sensors...[to] gather the data needed for a rapid procurement", according to Secretary of the Air Force Heather Wilson. Experimentation will examine logistics requirements, weapons and sensor issues, and future interoperability with partner forces.


title: Beechcraft T-6 Texan II

text: The Air Force expects to have the information it needs to potentially buy light attack aircraft in a future competition, without conducting a combat demonstration, based on data collected during the first round of the experiment and future data anticipated to be collected in the next phase of experimentation.


title: Beechcraft T-6 Texan II

text: During the last week of January 2018, a cluster of unexplained physiological events involving the T-6 occurred at Columbus, Vance, and Sheppard Air Force Bases. In response, the commander of Nineteenth Air Force, which is responsible for USAF pilot training, directed an "operational pause" in Texan II operations on 1 February 2018 to ensure aircrew safety. The pause was intended to enable the Air Force to "examine the root causes of the incidents, educate and listen to aircrew, develop and deliver mitigation solutions." The Air Force had established a general officer-led team to integrate and coordinate efforts across the Air Force to address aircrew unexplained physiological events earlier in 2018.


title: Beechcraft T-6 Texan II

text: In February 2018, the AT-6 Wolverine and the A-29 Super Tucano were named as the only two remaining aircraft in USAF's Light Attack/Armed Reconnaissance aircraft competition.


title: Beechcraft T-6 Texan II

text: The CT-156 Harvard II is a variant used for pilot instruction in the NATO Flying Training in Canada (NFTC), located at 15 Wing, Moose Jaw, Saskatchewan. They are leased to the Royal Canadian Air Force by the program's administrator, CAE. NFTC's Harvard II aircraft are almost identical in cockpit layout and performance to the American JPATS Texan IIs. Within NFTC, students fly the Harvard II in Phase 2 and 3 of the training program, and some will go on to fly the CT-155 Hawk jet trainer also used by NFTC for Phase 4 (Moose Jaw) and Phase 5 Fighter Lead-In Training (4 Wing, Cold Lake, Alberta). NFTC had 25 Harvard II aircraft owned and maintained by Bombardier, although one was lost following a non-fatal crash in 2011. CAE took over the program in 2015.


title: Beechcraft T-6 Texan II

text: On 9 June 2008, the Defense Security Cooperation Agency announced a possible FMS sale to Israel of 25 T-6As for the Israeli Air Force. In July 2009, Beechcraft delivered the first four of 20 T-6As under contract to the Israeli Air Force.


title: Beechcraft T-6 Texan II

text: On 16 December 2009, the first four of 15 T-6A aircraft were delivered to Tikrit, Iraq under a $210 million contract. No AT-6 aircraft were included as was previously reported. The last four T-6As reached Iraq on 9 November 2010.


title: Beechcraft T-6 Texan II

text: On 13 May 2014, the US State Department approved an order for 24 T-6C aircraft for use as trainers by the Iraqi Air Force. The sale was worth US$790 million and was part of a larger one billion dollar deal.


title: Beechcraft T-6 Texan II

text: On 9 January 2012, Mexico purchased six T-6C+ aircraft for the Mexican Air Force to begin replacing their Pilatus PC-7 trainers. On 24 October 2013, Hawker Beechcraft announced a follow-on order of an additional six T-6C+ aircraft for the Mexican Air Force, bringing the total ordered to 12. The Mexican Navy also ordered two T-6C+ Trainers in March 2014.


title: Beechcraft T-6 Texan II

text: The New Zealand Government announced the purchase of 11 T-6Cs for the Royal New Zealand Air Force for NZ$154 million, on 27 January 2014 to replace the PAC CT/4 Airtrainer, with all aircraft delivered by February 2015. The first training course using the type began early 2016. The T-6Cs are expected to remain in service with the RNZAF for 30 years.


title: Beechcraft T-6 Texan II

text: On 24 October 2014, the UK Ministry of Defence announced its preferred bidder for the UK Military Flying Training System programme. Ascent's system will involve T-6C Texan IIs in the basic trainer role for both Royal Air Force and Royal Navy pilots. The contract for ten aircraft was signed by Affinity Flying Training Services and Beechcraft Defense on 4 February 2016. The T-6C trainers have replaced Shorts Tucano T1 aircraft.


title: Beechcraft T-6 Texan II

text: In October 2017, the Argentine Air Force received the first four of 12 T-6C+ aircraft purchased from Textron Aviation and a further two in June 2018.


title: Beechcraft T-6 Texan II

text: In October 2019, U.S. State Department approved the possible Foreign Military Sale of 12 T-6Cs to Tunisia at an estimated cost of $234 million, including related spares, ground support equipment, and support. The sale is intended to provide replacement for the aging trainer fleet of Tunisian Air Force and to train pilots for counter-terrorism and border security missions.


title: Petroleum jelly

text: Petroleum jelly, petrolatum, white petrolatum, soft paraffin, or multi-hydrocarbon, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons (with carbon numbers mainly higher than 25), originally promoted as a topical ointment for its healing properties. The Vaseline brand is a well known American brand of petroleum jelly since 1870.


title: Petroleum jelly

text: After petroleum jelly became a medicine-chest staple, consumers began to use it for cosmetic purposes and for many ailments including toenail fungus, genital rashes (non-STD), nosebleeds, diaper rash, and common colds. Its folkloric medicinal value as a "cure-all" has since been limited by better scientific understanding of appropriate and inappropriate uses. It is recognized by the U.S. Food and Drug Administration (FDA) as an approved over-the-counter (OTC) skin protectant and remains widely used in cosmetic skin care, where it is often loosely referred to as mineral oil.


title: Petroleum jelly

text: Marco Polo in 1273 described the oil exportation of Baku oil by hundreds of camels and ships for burning and as an ointment for treating mange.


title: Petroleum jelly

text: Native Americans discovered the use of petroleum jelly for protecting and healing skin. Sophisticated oil pits had been built as early as 1415–1450 in Western Pennsylvania. In 1859, workers operating the United States of America's first oil rigs noticed a paraffin-like material forming on rigs in the course of investigating malfunctions. Believing the substance hastened healing, the workers used the jelly on cuts and burns.


title: Petroleum jelly

text: Robert Chesebrough, a young chemist whose previous work of distilling fuel from the oil of sperm whales had been rendered obsolete by petroleum, went to Titusville, Pennsylvania, US, to see what new materials had commercial potential. Chesebrough took the unrefined black rod wax, as the drillers called it, back to his laboratory to refine it and explore potential uses. He discovered that by distilling the lighter, thinner oil products from the rod wax, he could create a light-colored gel. Chesebrough patented the process of making petroleum jelly by in 1872. The process involved vacuum distillation of the crude material followed by filtration of the still residue through bone char. Chesebrough traveled around New York demonstrating the product to encourage sales by burning his skin with acid or an open flame, then spreading the ointment on his injuries and showing his past injuries healed, he claimed, by his miracle product. He opened his first factory in 1870 in Brooklyn using the name Vaseline.


title: Petroleum jelly

text: Petroleum jelly is a mixture of hydrocarbons, with a melting point that depends on the exact proportions. The melting point is typically between . It is flammable only when heated to liquid; then the fumes will light, not the liquid itself, so a wick material is needed to ignite petroleum jelly. It is colorless (or of a pale yellow color when not highly distilled), translucent, and devoid of taste and smell when pure. It does not oxidize on exposure to the air and is not readily acted on by chemical reagents. It is insoluble in water. It is soluble in dichloromethane, chloroform, benzene, diethyl ether, carbon disulfide and turpentine. Petroleum jelly is slightly soluble in alcohol. It acts as a plasticizer on polypropylene (PP), but is compatible with most other plastics. It is a semi-solid, in that it holds its shape indefinitely like a solid, but it can be forced to take the shape of its container without breaking apart, like a liquid, though it does not flow on its own.


title: Petroleum jelly

text: Depending on the specific application of petroleum jelly, it may be USP, B.P., or Ph. Eur. grade. This pertains to the processing and handling of the petroleum jelly so it is suitable for medicinal and personal-care applications.


title: Petroleum jelly

text: Most uses of petroleum jelly exploit its lubricating and coating properties, including use on dry lips and dry skin. Below are some examples of the uses of petroleum jelly.


title: Petroleum jelly

text: Vaseline brand First Aid Petroleum Jelly, or carbolated petroleum jelly containing phenol to give the jelly additional antibacterial effect, has been discontinued. During World War II, a variety of petroleum jelly called "red veterinary petrolatum", or Red Vet Pet for short, was often included in life raft survival kits. Acting as a sunscreen, it provides protection against ultraviolet rays.


title: Petroleum jelly

text: The American Academy of Dermatology recommends keeping skin injuries moist with petroleum jelly to reduce scarring. A verified medicinal use is to protect and prevent moisture loss of the skin of a patient in the initial post-operative period following laser skin resurfacing.


title: Petroleum jelly

text: Petroleum jelly is used extensively by otolaryngologists—ear, nose, and throat surgeons—for nasal moisture and epistaxis treatment, and to combat nasal crusting. Large studies have found petroleum jelly applied to the nose for short durations to have no significant side effects.


title: Petroleum jelly

text: Most petroleum jelly today is used as an ingredient in skin lotions and cosmetics, providing various types of skin care and protection by minimizing friction or reducing moisture loss, or by functioning as a grooming aid (e.g., pomade). It is also used for treating dry scalp and dandruff.


title: Petroleum jelly

text: By reducing the loss of moisture via transepidermal water loss, petroleum jelly can prevent chapped hands and lips, and soften nail cuticles.


title: Petroleum jelly

text: This property is exploited to provide heat insulation: petroleum jelly can be used to keep swimmers warm in water when training, or during channel crossings or long ocean swims. It can prevent chilling of the face due to evaporation of skin moisture during cold weather outdoor sports.


title: Petroleum jelly

text: In the first part of the twentieth century, petroleum jelly, either pure or as an ingredient, was also popular as a hair pomade. When used in a 50/50 mixture with pure beeswax, it makes an effective moustache wax.


title: Petroleum jelly

text: Petroleum jelly can be used to reduce the friction between skin and clothing during various sport activities, for example to prevent chafing of the seat region of cyclists, or the nipples of long distance runners wearing loose T-shirts, and is commonly used in the groin area of wrestlers and footballers.


title: Petroleum jelly

text: Petroleum jelly is commonly used as a personal lubricant, because it does not dry out like water-based lubricants, and has a distinctive "feel", different from that of K-Y and related methylcellulose products. However, it is not recommended for use with condoms during sexual activity, as it increases the chance of rupture.


title: Petroleum jelly

text: Petroleum jelly can be used to coat corrosion-prone items such as metallic trinkets, non-stainless steel blades, and gun barrels prior to storage as it serves as an excellent and inexpensive water repellent. It is used as an environmentally friendly underwater antifouling coating for motor boats and sailing yachts. It was recommended in the Porsche owner's manual as a preservative for light alloy (alleny) anodized Fuchs wheels to protect them against corrosion from road salts and brake dust.


title: Petroleum jelly

text: It can be used to finish and protect wood, much like a mineral oil finish. It is used to condition and protect smooth leather products like bicycle saddles, boots, motorcycle clothing, and used to put a shine on patent leather shoes (when applied in a thin coat and then gently buffed off).


title: Petroleum jelly

text: Petroleum jelly can be used to lubricate zippers and slide rules. It was also recommended by Porsche in maintenance training documentation for lubrication (after cleaning) of "Weatherstrips on Doors, Hood, Tailgate, Sun Roof". It is used in bullet lubricant compounds. Petrolatum is also used as a light lubricating grease as well as an anti-seize assembling grease.


title: Petroleum jelly

text: Petroleum jelly is a useful material when incorporated into candle wax formulas. It softens the overall blend, allows the candle to incorporate additional fragrance oil, and facilitates adhesion to the sidewall of the glass. Petroleum jelly is used to moisten nondrying modelling clay such as plasticine, as part of a mix of hydrocarbons including those with greater (paraffin wax) and lesser (mineral oil) molecular weights. It is used as a tack reducer additive to printing inks to reduce paper lint "picking" from uncalendered paper stocks. It can be used as a release agent for plaster molds and castings. It is used in the leather industry as a waterproofing cream.


title: Petroleum jelly

text: Petroleum jelly can be mixed with a high proportion of strong inorganic chlorates due to it acting as a plasticizer and a fuel source. An example of this is Cheddite C which consists of a ratio of 9:1, KClO to petroleum jelly. This mixture is unable to detonate without the use of a blasting cap. It is also used as a stabiliser in the manufacture of the propellant Cordite.


title: Petroleum jelly

text: Petroleum jelly can be used to fill copper or fibre-optic cables using plastic insulation to prevent the ingress of water, see icky-pick.


title: Petroleum jelly

text: Petroleum jelly can be used to coat the inner walls of terrariums to prevent animals crawling out and escaping.


title: Petroleum jelly

text: A stripe of petroleum jelly can be used to prevent the spread of a liquid. For example, it can be applied close to the hairline when using a home hair dye kit to prevent the hair dye from irritating or staining the skin. It is also used to prevent diaper rash.


title: Petroleum jelly

text: Petroleum jelly is sometimes used to protect the terminals on batteries. In automobiles, a silicone-based battery grease provides better protection as it is less likely to melt.


title: Petroleum jelly

text: Petroleum jelly is used to gently clean a variety of surfaces, ranging from makeup removal from faces to tar stain removal from leather.


title: Petroleum jelly

text: Petroleum jelly is used to moisturize the paws of dogs. It is a common ingredient in hairball remedies for domestic cats.


title: Petroleum jelly

text: A study published in 2017 found at most 1% Mineral Oil Aromatic Hydrocarbons (MOAH) in petroleum jelly, and less than 1% in petroleum jelly-based beauty products.