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Barometric Light
Barometric light is a name for the light that is emitted by a mercury-filled barometer tube when the tube is shaken. The discovery of this phenomenon in 1675 revealed the possibility of electric lighting. The phenomenon and its explanation The earliest barometers were simply glass tubes that were closed at one end and filled with mercury. The tube was then inverted and its open end was submerged in a cup of mercury. The mercury then drained out of the tube until the pressure of the mercury in the tube—as measured at the surface of the mercury in the cup—equaled the atmosphere's pressure on the same surface. In order to produce barometric light, the glass tube must be very clean and the mercury must be pure. If the barometer is then shaken, a band of light will appear on the glass at the meniscus of the mercury whenever the mercury moves downward. When mercury contacts glass, the mercury transfers electrons to the glass. Whenever the mercury pulls free of the glass, thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum and polarization. Its speed in a vacuum, 299 792 458 metres a second (m/s), is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Polinière
Pierre Polinière (8 September 1671 – 9 February 1734) was an early investigator of electricity and electrical phenomena, notably " barometric light", a form of gas-discharge light, which suggested the possibility of electric lighting. He also helped to introduce the scientific method in French universities. Biography Pierre Polinière was born in Coulonces, Calvados. He was the only child of Jean-Baptiste Poulynière and Françoise Vasnier. Pierre's father had inherited an estate in Coulonces in lower Normandy. However, when Pierre was 3 years old, his father died. Fortunately his mother recognized his potential and strove to get him a good education. After receiving a classical education at the University of Caen Normandy, two of his paternal uncles, who were Catholic clergymen, arranged to have him study philosophy at Harcourt College of the University of Paris. There he also studied mathematics under Pierre Varignon (1654–1722), an early advocate of calculus. In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorological Instrumentation And Equipment
Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not begin until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics, and more particularly in the latter half of the 20th century the development of the computer (allowing for the automated solution of a great many modelling equations) that significant breakthroughs in weather forecasting were achieved. An important branch of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water. Meteorological phenom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminescence
Luminescence is spontaneous emission of light by a substance not resulting from heat; or "cold light". It is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions or stress on a crystal. This distinguishes luminescence from incandescence, which is light emitted by a substance as a result of heating. Historically, radioactivity was thought of as a form of "radio-luminescence", although it is today considered to be separate since it involves more than electromagnetic radiation. The dials, hands, scales, and signs of aviation and navigational instruments and markings are often coated with luminescent materials in a process known as "luminising". Types The following are types of luminescence: *Chemiluminescence, the emission of light as a result of a chemical reaction **Bioluminescence, a result of biochemical reactions in a living organism ** Electrochemiluminescence, a result of an electrochemical reaction ** Lyolumine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighting
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting (using windows, skylights, or light shelves) is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants. Indoor lighting is usually accomplished using light fixtures, and is a key part of interior design. Lighting can also be an intrinsic component of landscape projects. History With the discovery of fire, the earliest form of artificial lighting used to illuminate an area were campfires or torches. As early as 400,000 years ago, fire was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franz Aepinus
Franz Ulrich Theodor Aepinus (13 December 172410 August 1802) was a German mathematician, scientist, and natural philosopher residing in the Russian Empire. Aepinus is best known for his researches, theoretical and experimental, in electricity and magnetism. Early life He was born at Rostock in the Duchy of Mecklenburg-Schwerin. He was descended from Johannes Aepinus (1499–1553), the first to adopt the Greek form (αἰπεινός) of the family name Hugk or Huck, and a leading theologian and controversialist at the time of the Protestant Reformation. Career After studying medicine for a time, Franz Aepinus devoted himself to the physical and mathematical sciences, in which he soon gained such distinction that he was admitted a member of the Prussian Academy of Sciences. In 1755, he was briefly the director of the Astronomisches Rechen-Institut. In 1757, he settled in St Petersburg as member of the Russian Academy of Sciences and professor of physics, and remained t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giovanni Battista Beccaria
Giovanni Battista Beccaria (; 3 October 1716 – 27 May 1781), Italian physicist, was born at Mondovì, and entered the religious Order of the Pious Schools or Piarists, in 1732, where he studied, and afterward taught, grammar and rhetoric. At the same time, he applied himself with success to mathematics. He became professor of experimental physics, first at Palermo and then at Rome, and was appointed to a similar position at Turin in 1748. He was afterwards made tutor to the young princes de Chablais and de Carignan, and continued to reside principally at Turin during the remainder of his life. In May 1755 he was elected a fellow of the Royal Society of London, and published several papers on electrical subjects in the '' Phil. Trans.''. In 1759, King Charles Emmanuel III of Sardinia, who had invited him to Turin, employed him to measure the degree of meridian arc In geodesy and navigation, a meridian arc is the curve between two points on the Earth's surface having the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anders Celsius
Anders Celsius (; 27 November 170125 April 1744) was a Swedish astronomer, physicist and mathematician. He was professor of astronomy at Uppsala University from 1730 to 1744, but traveled from 1732 to 1735 visiting notable observatories in Germany, Italy and France. He founded the Uppsala Astronomical Observatory in 1741, and in 1742 proposed (an inverted form of) the Centigrade temperature scale which was later renamed Celsius in his honour. Early life and education Anders Celsius was born in Uppsala, Sweden, on 27 November 1701. His family originated from Ovanåker in the province of Hälsingland. Their family estate was at ''Doma'', also known as ''Höjen'' or ''Högen'' (locally as ''Högen 2''). The name ''Celsius'' is a latinization of the estate's name (Latin ''celsus'' "mound"). As the son of an astronomy professor, Nils Celsius, nephew of botanist Olof Celsius and the grandson of the mathematician Magnus Celsius and the astronomer Anders Spole, Celsius chose a career ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a ''perfect'' vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is considerably lower than atmospheric pressure. The Latin term ''in vacuo'' is used to describe an object that is surrounded by a vacuum. The ''quality'' of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. But ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver and was formerly named hydrargyrum ( ) from the Greek words, ''hydor'' (water) and ''argyros'' (silver). A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. Mercury occurs in deposits throughout the world mostly as cinnabar ( mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis Hauksbee
Francis Hauksbee the Elder FRS (1660–1713), also known as Francis Hawksbee, was an 18th-century English scientist best known for his work on electricity and electrostatic repulsion. Biography Francis Hauksbee was the son of draper and common councillor Richard Hauksbee and his wife Mary. He was baptized on 27 May 1660 in the parish of St Mary-at-the-Walls, Colchester. He was the fifth of five sons. In 1673 Hauksbee entered Colchester Royal Grammar School. From 1678 to at least 1685 he apprenticed as a draper in the City of London, initially to his eldest brother. He was married no later than May 1687, when a daughter was born. Five of his eight children survived infancy. From 1687 to 1703, he may have run his own drapery shop. From at least March 1701, he lived at Giltspur Street, where he made air-pumps and pneumatic engines. The transition from drapery to scientific instrumentation and experimentation is not well documented. Historians have had to speculate about the even ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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