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Diffraction Grating
In optics, a diffraction grating is an optical grating with a periodic structure that diffraction, diffracts light, or another type of electromagnetic radiation, into several beams traveling in different directions (i.e., different diffraction angles). The emerging coloration is a form of structural coloration. The directions or diffraction angles of these beams depend on the wave (light) Angle of incidence (optics), incident angle to the diffraction grating, the spacing or periodic distance between adjacent diffracting elements (e.g., parallel slits for a transmission grating) on the grating, and the wavelength of the incident light. The grating acts as a dispersion (optics), dispersive element. Because of this, diffraction gratings are commonly used in monochromators and spectrometers, but other applications are also possible such as optical encoders for high-precision motion control and wavefront measurement. For typical applications, a reflection (optics), reflective grati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feather
Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant birds from other living groups. Although feathers cover most of the bird's body, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, and waterproofing. In addition, coloration helps in communication and protection. The study of feathers is called plumology (or plumage science). People use feathers in many ways that are practical, cultural, and religious. Feathers are both soft and excellent at trapping heat; thus, they are sometimes used in high-class bedding, especially pillows, blankets, and mattresses. They are also used as filling for winter clothing and outdoor bedding, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Augustus Rowland
Henry Augustus Rowland (November 27, 1848 – April 16, 1901) was an American physicist and Johns Hopkins educator. Between 1899 and 1901 he served as the first president of the American Physical Society. He is remembered for the high quality of the diffraction gratings he made and for the work he did with them on the solar spectrum. Early life, family and education Rowland was born in Honesdale, Pennsylvania, where his father Henry Augustus Rowland was a Presbyterian pastor. From an early age, the younger Rowland exhibited marked scientific tastes and spent his spare time in electrical and chemical experiments. He graduated from Rensselaer Polytechnic Institute in Troy, New York in 1870. Career After college, Rowland worked for the Western New York railway, but he did not like the work. He became an instructor in natural science at the University of Wooster in Wooster, Ohio. He resigned in order to return to Troy as assistant professor of physics at Rensselaer. Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greifswald
Greifswald (), officially the University and Hanseatic City of Greifswald (, Low German: ''Griepswoold'') is the fourth-largest city in the German state of Mecklenburg-Western Pomerania after Rostock, Schwerin and Neubrandenburg. In 2021 it surpassed Stralsund for the first time, and became the largest city in the Pomeranian part of the state. It sits on the River Ryck, at its mouth into the Danish Wiek, a sub-bay of the Bay of Greifswald, which is itself a sub-bay of the Bay of Pomerania of the Baltic Sea. It is the seat of the district of Vorpommern-Greifswald, Western Pomerania-Greifswald, and is located roughly in the middle between the two largest Pomeranian islands of Rügen and Usedom. The closest larger cities are Stralsund, Rostock, Szczecin and Schwerin. It lies west of the River Zarow, the historical cultural and linguistic boundary between West (west of the river) and Central Pomerania (east of the river). The city derives its name from the dukes of Pomerania, the Hous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedrich Adolph Nobert
Friedrich Adolph Nobert (17 January 1806 – 21 February 1881) was a Pomerania, Pomeranian microscope designer who pioneered the use of diamond-ruled microscope slide gratings for accurate measurements. This extended further to diffraction gratings for use in spectrometers and the measurement of the solar spectrum by Anders Jonas Ångström which was published in 1868 made use of gratings made by Nobert. The finest lines were found to be at a distance of 0.1128 Micrometre, μm. Biography Nobert was born in Barth on the Baltic coast, where his father Johann Friedrich Nobert was a clockmaker. He was known as Fritz, and being the eldest son, he was expected to receive a technical education and continue as a clockmaker. A younger brother studied theology and became a pastor. He found his schooling insufficient for the clockmaking work and tried to study arithmetic, geometry and trigonometry on his own. He made a watch that could measure seconds, and corrected for temperature and sent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Line
A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission (electromagnetic radiation), emission or absorption (electromagnetic radiation), absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a Quantum mechanics, quantum system (usually atoms, but sometimes molecules or atomic nucleus, atomic nuclei) and a single photon. When a photon has about the right amount of photon energy, energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Augustin-Jean Fresnel
Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Isaac Newton, Newton's corpuscular theory of light, corpuscular theory, from the late 1830s until the end of the 19th century. He is perhaps better known for inventing the Catadioptric system, catadioptric (reflective/refractive) Fresnel lens and for pioneering the use of "stepped" lenses to extend the visibility of lighthouses, saving countless lives at sea. The simpler Dioptrics, dioptric (purely refractive) stepped lens, first proposed by Georges-Louis Leclerc, Comte de Buffon, Count Buffon and independently reinvented by Fresnel, is used in screen magnifying glass, magnifiers and in condenser lenses for overhead projectors. By expressing Christiaan Huygens, Huygens's principle of secondary waves and Thomas Young (scientist), Young's principle of interference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philosophical Transactions Of The Royal Society Of London
''Philosophical Transactions of the Royal Society'' is a scientific journal published by the Royal Society. In its earliest days, it was a private venture of the Royal Society's secretary. It was established in 1665, making it the second journal in the world exclusively devoted to science, after the ''Journal des sçavans'', and therefore also the world's longest-running scientific journal. It became an official society publication in 1752. The use of the word ''philosophical'' in the title refers to natural philosophy, which was the equivalent of what would now be generally called ''science''. Current publication In 1887 the journal expanded and divided into two separate publications, one serving the physical sciences (''Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences'') and the other focusing on the life sciences (''Philosophical Transactions of the Royal Society B: Biological Sciences''). Both journals now publish themed i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Young (scientist)
Thomas Young Fellow of the Royal Society, FRS (13 June 177310 May 1829) was a British polymath who made notable contributions to the fields of Visual perception, vision, light, solid mechanics, energy, physiology, language, harmony, musical harmony, and Egyptology. He was instrumental in the decipherment of Egyptian hieroglyphs, specifically the Rosetta Stone. Young has been described as "The Last Man Who Knew Everything". His work influenced that of William Herschel, Hermann von Helmholtz, James Clerk Maxwell, and Albert Einstein. Young is credited with establishing Christiaan Huygens' wave theory of light, in contrast to the corpuscular theory of Isaac Newton. Young's work was subsequently supported by the work of Augustin-Jean Fresnel. Personal life Young belonged to a Quaker family of Milverton, Somerset, where he was born in 1773, the eldest of ten children. By the age of fourteen, Young had learned Greek language, Greek, Latin, French language, French, Italian language, It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Von Fraunhofer
Joseph Ritter von Fraunhofer (; ; 6 March 1787 – 7 June 1826) was a German physicist and optical lens manufacturer. He made optical glass, an achromatic telescope, and objective lenses. He developed diffraction grating and also invented the spectroscope. In 1814, he discovered and studied the dark absorption lines in the spectrum of the sun now known as Fraunhofer lines. The German research organization Fraunhofer Society, which is Europe's biggest Society for the advancement of applied research, is named after him. Fraunhofer lines are used in astronomy to determine the composition of celestial bodies. His epitaph reads , Latin for Biography Joseph Fraunhofer was the 11th child, born into a Roman Catholic family in Straubing, in the Electorate of Bavaria, to Franz Xaver Fraunhofer and Maria Anna Fröhlich. His father and paternal grandfather Johann Michael had been master glassmakers in Straubing. Fröhlich's family also came from a lineage of glassmakers going back to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Rittenhouse
David Rittenhouse (April 8, 1732 – June 26, 1796) was an American astronomer, inventor, clockmaker, mathematician, surveyor, scientific instrument craftsman, and public official. Rittenhouse was a member of the American Philosophical Society and the first director of the United States Mint. Early life and education Rittenhouse was born on April 8, 1732, in Rittenhousetown, in Germantown, along Paper Mill Run, a small tributary of the Wissahickon Creek. His great-grandfather, who was born in the Rhineland, emigrated to Pennsylvania in 1688. When his uncle, William Rittenhouse, died, David inherited his uncle's carpentry tools and instructional books. At a young age, David showed a high level of intelligence by creating a working scale model of his great-grandfather William Rittenhouse's paper mill. He built other scale models in his youth, like a working waterwheel. David never attended elementary school—he was self-taught from his family's books, and he showed great abil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philadelphia
Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the United States, with a population of 1,603,797 in the 2020 United States census, 2020 census. The city is the urban core of the Philadelphia metropolitan area (sometimes called the Delaware Valley), the nation's Metropolitan statistical area, seventh-largest metropolitan area and ninth-largest combined statistical area with 6.245 million residents and 7.379 million residents, respectively. Philadelphia was founded in 1682 by William Penn, an English Americans, English Quakers, Quaker and advocate of Freedom of religion, religious freedom, and served as the capital of the Colonial history of the United States, colonial era Province of Pennsylvania. It then played a historic and vital role during the American Revolution and American Revolutionary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
