Nature is a British multidisciplinary scientific journal, first published on 4 November 1869. It is one of the most recognizable scientific journals in the world, was ranked the world's most cited scientific journal by the Science Edition of the 2010 Journal Citation Reports and is ascribed an impact factor of 40.137, making it one of the world's top academic journals. It is one of the few remaining academic journals that publishes original research across a wide range of scientific fields. Research scientists are the primary audience for the journal, but summaries and accompanying articles are intended to make many of the most important papers understandable to scientists in other fields and the educated public. Towards the front of each issue are editorials and feature articles on issues of general interest to scientists, including current affairs, science funding, scientific ethics and research breakthroughs. There are sections on books and short science fiction stories; the remainder of the journal consists of research papers, which are dense and technical.
Because of strict limits on the length of papers the printed text is a summary of the work in question with many details relegated to accompanying supplementary material on the journal's website. There are many fields of research in which important new advances and original research are published as either articles or letters in Nature; the papers that have been published in this journal are internationally acclaimed for maintaining high research standards. Fewer than 8% of submitted papers are accepted for publication. In 2007 Nature received the Prince of Asturias Award for Humanity; the enormous progress in science and mathematics during the 19th century was recorded in journals written in German or French, as well as in English. Britain underwent enormous technological and industrial changes and advances in the latter half of the 19th century. In English the most respected scientific journals of this time were the refereed journals of the Royal Society, which had published many of the great works from Isaac Newton, Michael Faraday through to early works from Charles Darwin.
In addition, during this period, the number of popular science periodicals doubled from the 1850s to the 1860s. According to the editors of these popular science magazines, the publications were designed to serve as "organs of science", in essence, a means of connecting the public to the scientific world. Nature, first created in 1869, was not the first magazine of its kind in Britain. One journal to precede Nature was Recreative Science: A Record and Remembrancer of Intellectual Observation, created in 1859, began as a natural history magazine and progressed to include more physical observational science and technical subjects and less natural history; the journal's name changed from its original title to Intellectual Observer: A Review of Natural History, Microscopic Research, Recreative Science and later to the Student and Intellectual Observer of Science and Art. While Recreative Science had attempted to include more physical sciences such as astronomy and archaeology, the Intellectual Observer broadened itself further to include literature and art as well.
Similar to Recreative Science was the scientific journal Popular Science Review, created in 1862, which covered different fields of science by creating subsections titled "Scientific Summary" or "Quarterly Retrospect", with book reviews and commentary on the latest scientific works and publications. Two other journals produced in England prior to the development of Nature were the Quarterly Journal of Science and Scientific Opinion, established in 1864 and 1868, respectively; the journal most related to Nature in its editorship and format was The Reader, created in 1864. These similar journals all failed; the Popular Science Review survived longest, lasting 20 years and ending its publication in 1881. The Quarterly Journal, after undergoing a number of editorial changes, ceased publication in 1885; the Reader terminated in 1867, Scientific Opinion lasted a mere 2 years, until June 1870. Not long after the conclusion of The Reader, a former editor, Norman Lockyer, decided to create a new scientific journal titled Nature, taking its name from a line by William Wordsworth: "To the solid ground of nature trusts the Mind that builds for aye".
First owned and published by Alexander Macmillan, Nature was similar to its predecessors in its attempt to "provide cultivated readers with an accessible forum for reading about advances in scientific knowledge." Janet Browne has proposed that "far more than any other science journal of the period, Nature was conceived and raised to serve polemic purpose." Many of the early editions of Nature consisted of articles written by members of a group that called itself the X Club, a group of scientists known for having liberal and somewhat controversial scientific beliefs relative to the time period. Initiated by Thomas Henry Huxley, the group consisted of such important scientists as Joseph Dalton Hooker, Herbert Spencer, John Tyndall, along with another five scientists and mathematicians, it was in part its scientific liberality that made Nature a longer-lasti
The metre or meter is the base unit of length in the International System of Units. The SI unit symbol is m; the metre is defined as the length of the path travelled by light in vacuum in 1/299 792 458 of a second. The metre was defined in 1793 as one ten-millionth of the distance from the equator to the North Pole – as a result the Earth's circumference is 40,000 km today. In 1799, it was redefined in terms of a prototype metre bar. In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted; the imperial inch is defined as 0.0254 metres. One metre is about 3 3⁄8 inches longer than a yard, i.e. about 39 3⁄8 inches. Metre is the standard spelling of the metric unit for length in nearly all English-speaking nations except the United States and the Philippines, which use meter. Other Germanic languages, such as German and the Scandinavian languages spell the word meter. Measuring devices are spelled "-meter" in all variants of English.
The suffix "-meter" has the same Greek origin as the unit of length. The etymological roots of metre can be traced to the Greek verb μετρέω and noun μέτρον, which were used for physical measurement, for poetic metre and by extension for moderation or avoiding extremism; this range of uses is found in Latin, French and other languages. The motto ΜΕΤΡΩ ΧΡΩ in the seal of the International Bureau of Weights and Measures, a saying of the Greek statesman and philosopher Pittacus of Mytilene and may be translated as "Use measure!", thus calls for both measurement and moderation. In 1668 the English cleric and philosopher John Wilkins proposed in an essay a decimal-based unit of length, the universal measure or standard based on a pendulum with a two-second period; the use of the seconds pendulum to define length had been suggested to the Royal Society in 1660 by Christopher Wren. Christiaan Huygens had observed that length to be 39.26 English inches. No official action was taken regarding these suggestions.
In 1670 Gabriel Mouton, Bishop of Lyon suggested a universal length standard with decimal multiples and divisions, to be based on a one-minute angle of the Earth's meridian arc or on a pendulum with a two-second period. In 1675, the Italian scientist Tito Livio Burattini, in his work Misura Universale, used the phrase metro cattolico, derived from the Greek μέτρον καθολικόν, to denote the standard unit of length derived from a pendulum; as a result of the French Revolution, the French Academy of Sciences charged a commission with determining a single scale for all measures. On 7 October 1790 that commission advised the adoption of a decimal system, on 19 March 1791 advised the adoption of the term mètre, a basic unit of length, which they defined as equal to one ten-millionth of the distance between the North Pole and the Equator. In 1793, the French National Convention adopted the proposal. In 1791, the French Academy of Sciences selected the meridional definition over the pendular definition because the force of gravity varies over the surface of the Earth, which affects the period of a pendulum.
To establish a universally accepted foundation for the definition of the metre, more accurate measurements of this meridian were needed. The French Academy of Sciences commissioned an expedition led by Jean Baptiste Joseph Delambre and Pierre Méchain, lasting from 1792 to 1799, which attempted to measure the distance between a belfry in Dunkerque and Montjuïc castle in Barcelona to estimate the length of the meridian arc through Dunkerque; this portion of the meridian, assumed to be the same length as the Paris meridian, was to serve as the basis for the length of the half meridian connecting the North Pole with the Equator. The problem with this approach is that the exact shape of the Earth is not a simple mathematical shape, such as a sphere or oblate spheroid, at the level of precision required for defining a standard of length; the irregular and particular shape of the Earth smoothed to sea level is represented by a mathematical model called a geoid, which means "Earth-shaped". Despite these issues, in 1793 France adopted this definition of the metre as its official unit of length based on provisional results from this expedition.
However, it was determined that the first prototype metre bar was short by about 200 micrometres because of miscalculation of the flattening of the Earth, making the prototype about 0.02% shorter than the original proposed definition of the metre. Regardless, this length became the French standard and was progressively adopted by other countries in Europe; the expedition was fictionalised in Le mètre du Monde. Ken Alder wrote factually about the expedition in The Measure of All Things: the seven year odyssey and hidden error that transformed the world. In 1867 at the second general conference of the International Association of Geodesy held in Berlin, the question of an international standard unit of length was discussed in order to combine the measurements made in different countries to determine the size and shape of the Earth; the conference recommended the adoption of the metre and the creation of an internatio
Similitude is a concept applicable to the testing of engineering models. A model is said to have similitude with the real application if the two share geometric similarity, kinematic similarity and dynamic similarity. Similarity and similitude are interchangeable in this context; the term dynamic similitude is used as a catch-all because it implies that geometric and kinematic similitude have been met. Similitude's main application is in hydraulic and aerospace engineering to test fluid flow conditions with scaled models, it is the primary theory behind many textbook formulas in fluid mechanics. The concept of similitude is tied to dimensional analysis. Engineering models are used to study complex fluid dynamics problems where calculations and computer simulations aren't reliable. Models are smaller than the final design, but not always. Scale models allow testing of a design prior to building, in many cases are a critical step in the development process. Construction of a scale model, must be accompanied by an analysis to determine what conditions it is tested under.
While the geometry may be scaled, other parameters, such as pressure, temperature or the velocity and type of fluid may need to be altered. Similitude is achieved when testing conditions are created such that the test results are applicable to the real design; the following criteria are required to achieve similitude. Kinematic similarity – fluid flow of both the model and real application must undergo similar time rates of change motions. Dynamic similarity – ratios of all forces acting on corresponding fluid particles and boundary surfaces in the two systems are constant. To satisfy the above conditions the application is analyzed. Dimensional analysis is used to express the system with as few independent variables and as many dimensionless parameters as possible; the values of the dimensionless parameters are held to be the same for both the scale model and application. This can be done because they are dimensionless and will ensure dynamic similitude between the model and the application; the resulting equations are used to derive scaling laws.
It is impossible to achieve strict similitude during a model test. The greater the departure from the application's operating conditions, the more difficult achieving similitude is. In these cases some aspects of similitude may be neglected, focusing on only the most important parameters; the design of marine vessels remains more of an art than a science in large part because dynamic similitude is difficult to attain for a vessel, submerged: a ship is affected by wind forces in the air above it, by hydrodynamic forces within the water under it, by wave motions at the interface between the water and the air. The scaling requirements for each of these phenomena differ, so models cannot replicate what happens to a full sized vessel nearly so well as can be done for an aircraft or submarine—each of which operates within one medium. Similitude is a term used in fracture mechanics relating to the strain life approach. Under given loading conditions the fatigue damage in an un-notched specimen is comparable to that of a notched specimen.
Similitude suggests that the component fatigue life of the two objects will be similar. Consider a submarine modeled at 1/40th scale; the application operates in sea water at 0.5 °C, moving at 5 m/s. The model will be tested in fresh water at 20 °C. Find the power required for the submarine to operate at the stated speed. A free body diagram is constructed and the relevant relationships of force and velocity are formulated using techniques from continuum mechanics; the variables which describe the system are: This example has five independent variables and three fundamental units. The fundamental units are: metre, second. Invoking the Buckingham π theorem shows that the system can be described with two dimensionless numbers and one independent variable. Dimensional analysis is used to re-arrange the units to form the Reynolds number and pressure coefficient; these dimensionless numbers account for all the variables listed above except F, which will be the test measurement. Since the dimensionless parameters will stay constant for both the test and the real application, they will be used to formulate scaling laws for the test.
Scaling laws: R e = ⟶ V model = V application × × × C p =, F
Two geometrical objects are called similar if they both have the same shape, or one has the same shape as the mirror image of the other. More one can be obtained from the other by uniformly scaling with additional translation and reflection; this means that either object can be rescaled and reflected, so as to coincide with the other object. If two objects are similar, each is congruent to the result of a particular uniform scaling of the other. A modern and novel perspective of similarity is to consider geometrical objects similar if one appears congruent to the other when zoomed in or out at some level. For example, all circles are similar to each other, all squares are similar to each other, all equilateral triangles are similar to each other. On the other hand, ellipses are not all similar to each other, rectangles are not all similar to each other, isosceles triangles are not all similar to each other. If two angles of a triangle have measures equal to the measures of two angles of another triangle the triangles are similar.
Corresponding sides of similar polygons are in proportion, corresponding angles of similar polygons have the same measure. This article assumes that a scaling can have a scale factor of 1, so that all congruent shapes are similar, but some school textbooks exclude congruent triangles from their definition of similar triangles by insisting that the sizes must be different if the triangles are to qualify as similar. In geometry two triangles, △ABC and △A′B′C′, are similar if and only if corresponding angles have the same measure: this implies that they are similar if and only if the lengths of corresponding sides are proportional, it can be shown that two triangles having congruent angles are similar, that is, the corresponding sides can be proved to be proportional. This is known as the AAA similarity theorem. Note that the "AAA" is a mnemonic: each one of the three A's refers to an "angle". Due to this theorem, several authors simplify the definition of similar triangles to only require that the corresponding three angles are congruent.
There are several statements each of, necessary and sufficient for two triangles to be similar: The triangles have two congruent angles, which in Euclidean geometry implies that all their angles are congruent. That is:If ∠BAC is equal in measure to ∠B′A′C′, ∠ABC is equal in measure to ∠A′B′C′ this implies that ∠ACB is equal in measure to ∠A′C′B′ and the triangles are similar. All the corresponding sides have lengths in the same ratio:AB/A′B′ = BC/B′C′ = AC/A′C′; this is equivalent to saying. Two sides have lengths in the same ratio, the angles included between these sides have the same measure. For instance:AB/A′B′ = BC/B′C′ and ∠ABC is equal in measure to ∠A′B′C′; this is known as the SAS similarity criterion. The "SAS" is a mnemonic: each one of the two S's refers to a "side"; when two triangles △ABC and △A′B′C′ are similar, one writes △ABC ∼ △A′B′C′. There are several elementary results concerning similar triangles in Euclidean geometry: Any two equilateral triangles are similar. Two triangles, both similar to a third triangle, are similar to each other.
Corresponding altitudes of similar triangles have the same ratio as the corresponding sides. Two right triangles are similar if one other side have lengths in the same ratio. Given a triangle △ABC and a line segment DE one can, with ruler and compass, find a point F such that △ABC ∼ △DEF; the statement that the point F satisfying this condition exists is Wallis's postulate and is logically equivalent to Euclid's parallel postulate. In hyperbolic geometry similar triangles are congruent. In the axiomatic treatment of Euclidean geometry given by G. D. Birkhoff the SAS similarity criterion given above was used to replace both Euclid's Parallel Postulate and the SAS axiom which enabled the dramatic shortening of Hilbert's axioms. Similar triangles provide the basis for many synthetic proofs in Euclidean geometry. Among the elementary results that can be proved this way are: the angle bisector theorem, the geometric mean theorem, Ceva's theorem, Menelaus's theorem and the Pythagorean theorem. Similar triangles provide the foundations for right triangle trigonometry.
The concept of similarity extends to polygons with more than three sides. Given any two similar polygons, corresponding sides taken in the same sequence are proportional and corresponding angles taken in the same sequence are equal in measure. However, proportionality of corresponding sides is not by itself sufficient to prove similarity for polygons beyond triangles. Equality of all angles in sequence is not sufficient to guarantee similarity. A sufficient condition for similarity of polygons is that corresponding sides and diagonals are proportional. For given n, all regular n-gons are similar. Several types of curves have the property; these include: Circles Parabolas Hyperbolas of a specific eccentricity Ellipses of a specific eccentricity Catenaries Graphs of the logarithm function for different bases Graphs of the exponential function for different bases Logarithmic spirals are self-similar A similarity of a Euclidean space is a bijection f from the space onto itself that multiplies all distances
In mathematics, a theorem is a statement, proven on the basis of established statements, such as other theorems, accepted statements, such as axioms. A theorem is a logical consequence of the axioms; the proof of a mathematical theorem is a logical argument for the theorem statement given in accord with the rules of a deductive system. The proof of a theorem is interpreted as justification of the truth of the theorem statement. In light of the requirement that theorems be proved, the concept of a theorem is fundamentally deductive, in contrast to the notion of a scientific law, experimental. Many mathematical theorems are conditional statements. In this case, the proof deduces the conclusion from conditions called premises. In light of the interpretation of proof as justification of truth, the conclusion is viewed as a necessary consequence of the hypotheses, that the conclusion is true in case the hypotheses are true, without any further assumptions. However, the conditional could be interpreted differently in certain deductive systems, depending on the meanings assigned to the derivation rules and the conditional symbol.
Although they can be written in a symbolic form, for example, within the propositional calculus, theorems are expressed in a natural language such as English. The same is true of proofs, which are expressed as logically organized and worded informal arguments, intended to convince readers of the truth of the statement of the theorem beyond any doubt, from which a formal symbolic proof can in principle be constructed; such arguments are easier to check than purely symbolic ones—indeed, many mathematicians would express a preference for a proof that not only demonstrates the validity of a theorem, but explains in some way why it is true. In some cases, a picture alone may be sufficient to prove a theorem; because theorems lie at the core of mathematics, they are central to its aesthetics. Theorems are described as being "trivial", or "difficult", or "deep", or "beautiful"; these subjective judgments vary not only from person to person, but with time: for example, as a proof is simplified or better understood, a theorem, once difficult may become trivial.
On the other hand, a deep theorem may be stated but its proof may involve surprising and subtle connections between disparate areas of mathematics. Fermat's Last Theorem is a well-known example of such a theorem. Logically, many theorems are of the form of an indicative conditional: if A B; such a theorem does not assert B, only that B is a necessary consequence of A. In this case A is called B the conclusion; the theorem "If n is an natural number n/2 is a natural number" is a typical example in which the hypothesis is "n is an natural number" and the conclusion is "n/2 is a natural number". To be proved, a theorem must be expressible as a formal statement. Theorems are expressed in natural language rather than in a symbolic form, with the intention that the reader can produce a formal statement from the informal one, it is common in mathematics to choose a number of hypotheses within a given language and declare that the theory consists of all statements provable from these hypotheses. These hypotheses are called axioms or postulates.
The field of mathematics known as proof theory studies formal languages and the structure of proofs. Some theorems are "trivial", in the sense that they follow from definitions and other theorems in obvious ways and do not contain any surprising insights. Some, on the other hand, may be called "deep", because their proofs may be long and difficult, involve areas of mathematics superficially distinct from the statement of the theorem itself, or show surprising connections between disparate areas of mathematics. A theorem might be simple to state and yet be deep. An excellent example is Fermat's Last Theorem, there are many other examples of simple yet deep theorems in number theory and combinatorics, among other areas. Other theorems have a known proof that cannot be written down; the most prominent examples are the Kepler conjecture. Both of these theorems are only known to be true by reducing them to a computational search, verified by a computer program. Many mathematicians did not accept this form of proof, but it has become more accepted.
The mathematician Doron Zeilberger has gone so far as to claim that these are the only nontrivial results that mathematicians have proved. Many mathematical theorems can be reduced to more straightforward computation, including polynomial identities, trigonometric identities and hypergeometric identities. To establish a mathematical statement as a theorem, a proof is required, that is, a line of reasoning from axioms in the system to the given statement must be demonstrated. However, the proof is considered as separate from the theorem statement. Although more than one proof may be known for a single theorem, only one proof is required to establish the status of a statement as a theorem; the Pythagorean theorem and the law of quadratic reciprocity are contenders for the title of theorem with the greatest number of distinct proofs. Theorems in mathematics and theories in science are fundamentally different in their epistemology. A scientific theory cannot be proved.
The ampere shortened to "amp", is the base unit of electric current in the International System of Units. It is named after André-Marie Ampère, French mathematician and physicist, considered the father of electrodynamics; the International System of Units defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier CGS measurement system had two different definitions of current, one the same as the SI's and the other using electric charge as the base unit, with the unit of charge defined by measuring the force between two charged metal plates; the ampere was defined as one coulomb of charge per second. In SI, the unit of charge, the coulomb, is defined as the charge carried by one ampere during one second. New definitions, in terms of invariant constants of nature the elementary charge, will take effect on 20 May 2019. SI defines ampere as follows: The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, placed one metre apart in vacuum, would produce between these conductors a force equal to 2×10−7 newtons per metre of length.
Ampère's force law states that there is an attractive or repulsive force between two parallel wires carrying an electric current. This force is used in the formal definition of the ampere; the SI unit of charge, the coulomb, "is the quantity of electricity carried in 1 second by a current of 1 ampere". Conversely, a current of one ampere is one coulomb of charge going past a given point per second: 1 A = 1 C s. In general, charge Q is determined by steady current I flowing. Constant and average current are expressed in amperes and the charge accumulated, or passed through a circuit over a period of time is expressed in coulombs; the relation of the ampere to the coulomb is the same as that of the watt to the joule. The ampere was defined as one tenth of the unit of electric current in the centimetre–gram–second system of units; that unit, now known as the abampere, was defined as the amount of current that generates a force of two dynes per centimetre of length between two wires one centimetre apart.
The size of the unit was chosen so that the units derived from it in the MKSA system would be conveniently sized. The "international ampere" was an early realization of the ampere, defined as the current that would deposit 0.001118 grams of silver per second from a silver nitrate solution. More accurate measurements revealed that this current is 0.99985 A. Since power is defined as the product of current and voltage, the ampere can alternatively be expressed in terms of the other units using the relationship I=P/V, thus 1 ampere equals 1 W/V. Current can be measured by a multimeter, a device that can measure electrical voltage and resistance; the standard ampere is most realized using a Kibble balance, but is in practice maintained via Ohm's law from the units of electromotive force and resistance, the volt and the ohm, since the latter two can be tied to physical phenomena that are easy to reproduce, the Josephson junction and the quantum Hall effect, respectively. At present, techniques to establish the realization of an ampere have a relative uncertainty of a few parts in 107, involve realizations of the watt, the ohm and the volt.
Rather than a definition in terms of the force between two current-carrying wires, it has been proposed that the ampere should be defined in terms of the rate of flow of elementary charges. Since a coulomb is equal to 6.2415093×1018 elementary charges, one ampere is equivalent to 6.2415093×1018 elementary charges moving past a boundary in one second. The proposed change would define 1 A as being the current in the direction of flow of a particular number of elementary charges per second. In 2005, the International Committee for Weights and Measures agreed to study the proposed change; the new definition was discussed at the 25th General Conference on Weights and Measures in 2014 but for the time being was not adopted. The current drawn by typical constant-voltage energy distribution systems is dictated by the power consumed by the system and the operating voltage. For this reason the examples given below are grouped by voltage level. Current notebook CPUs: up to 15...45 A Current high-end CPUs: up to 55...120 A Hearing aid: 700 µA USB charging adapter: 2 A A typical motor vehicle has a 12 V battery.
The various accessories that are powered by the battery might include: Instrument panel light: 166 mA Headlight: 5 A Starter motor on a smaller car: 50 A to 200 A Most Canada and United States domestic power suppliers run at 120 V. Household circuit breakers provide a maximum of 15 A or 20 A of current to a given set of outlets. USB charging adapter: 83 mA 22-inch/56-centimeter portable television: 290 mA Tungsten light bulb: 500–830 mA Toaster, kettle: 12.5 A Hair dryer: 15 A Most European domestic power supplies run at 230 V, most Commonwealth domestic power supplies run at 2
John William Strutt, 3rd Baron Rayleigh
John William Strutt, 3rd Baron Rayleigh, was a British scientist who made extensive contributions to both theoretical and experimental physics. He spent all of his academic career at the University of Cambridge. Among many honours, he received the 1904 Nobel Prize in Physics "for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies." He served as President of the Royal Society from 1905 to 1908 and as Chancellor of the University of Cambridge from 1908 to 1919. Rayleigh provided the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, a phenomenon now known as "Rayleigh scattering", which notably explains why the sky is blue, he studied and described transverse surface waves in solids, now known as "Rayleigh waves". He contributed extensively to fluid dynamics, with concepts such as the Rayleigh number, Rayleigh flow, the Rayleigh–Taylor instability, Rayleigh's criterion for the stability of Taylor–Couette flow.
He formulated the circulation theory of aerodynamic lift. In optics, Rayleigh proposed a well known criterion for angular resolution, his derivation of the Rayleigh–Jeans law for classical black-body radiation played an important role in birth of quantum mechanics. Rayleigh's textbook The Theory of Sound is still used today by engineers. Strutt was born on 12 November 1842 at Langford Grove in Essex. In his early years he suffered from poor health, he attended Eton College and Harrow School, before going on to the University of Cambridge in 1861 where he studied mathematics at Trinity College, Cambridge. He obtained a Bachelor of Arts degree in 1865, a Master of Arts in 1868, he was subsequently elected to a Fellowship of Trinity. He held the post until his marriage to Evelyn Balfour, daughter of James Maitland Balfour, in 1871, he had three sons with her. In 1873, on the death of his father, John Strutt, 2nd Baron Rayleigh, he inherited the Barony of Rayleigh, he was the second Cavendish Professor of Physics at the University of Cambridge, from 1879 to 1884.
He first described dynamic soaring in the British journal Nature. From 1887 to 1905 he was Professor of Natural Philosophy at the Royal Institution. Around the year 1900 Rayleigh developed the duplex theory of human sound localisation using two binaural cues, interaural phase difference and interaural level difference; the theory posits that we use two primary cues for sound lateralisation, using the difference in the phases of sinusoidal components of the sound and the difference in amplitude between the two ears. In 1919, Rayleigh served as President of the Society for Psychical Research; as an advocate that simplicity and theory be part of the scientific method, Rayleigh argued for the principle of similitude. Rayleigh was elected Fellow of the Royal Society on 12 June 1873, served as president of the Royal Society from 1905 to 1908. From time to time Rayleigh participated in the House of Lords, he died on 30 June 1919, in Essex. He was succeeded, as the 4th Lord Rayleigh, by his son Robert John Strutt, another well-known physicist.
Lord Rayleigh was buried in the graveyard of All Saints' Church in Terling in Essex. The rayl unit of acoustic impedance is named after him. Rayleigh was an Anglican. Though he did not write about the relationship of science and religion, he retained a personal interest in spiritual matters; when his scientific papers were to be published in a collection by the Cambridge University Press, Strutt wanted to include a religious quotation from the Bible, but he was discouraged from doing so, as he reported: When I was bringing out my Scientific Papers I proposed a motto from the Psalms, "The Works of the Lord are great, sought out of all them that have pleasure therein." The Secretary to the Press suggested with many apologies that the reader might suppose that I was the Lord. Still, he had his wish and the quotation was printed in the five-volume collection of scientific papers. In a letter to a family member, he wrote about his rejection of materialism and spoke of Jesus Christ as a moral teacher: I have never thought the materialist view possible, I look to a power beyond what we see, to a life in which we may at least hope to take part.
What is more, I think that Christ and indeed other spiritually gifted men see further and truer than I do, I wish to follow them as far as I can. He was an early member of the Society for Psychical Research, he remained open to the possibility of supernatural phenomena. Rayleigh was the president of the SPR in 1919, he gave a presidential address in the year of his death but did not come to any definite conclusions. The lunar crater Rayleigh as well as the Martian crater Rayleigh were named in his honour; the asteroid 22740 Rayleigh was named after him on 1 June 2007. A type of surface waves are known as Rayleigh waves; the rayl, a unit of specific acoustic impedance, is named for him. Rayleigh was awarded with: Smith's Prize Royal Medal Matteucci Medal Member of the Royal Swedish Academy of Sciences Copley Medal Nobel Prize for Physics Elliott Cresson Medal Rumford Medal Lord Rayleigh was among the original recipients of the O