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Siphon
A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir from which it came. There are two leading theories about how siphons cause liquid to flow uphill, against gravity, without being pumped, and powered only by gravity. The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push the liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a baromet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal's Siphon
A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir from which it came. There are two leading theories about how siphons cause liquid to flow uphill, against gravity, without being pumped, and powered only by gravity. The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push the liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a baromet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythagorean Cup
A Pythagorean cup (also known as a Pythagoras cup, Greedy Cup, Cup of Justice or Tantalus cup) is a practical joke device in a form of a drinking cup, credited to Pythagoras of Samos. When it is filled beyond a certain point, a siphoning effect causes the cup to drain its entire contents through the base. The cup can be used to learn about greed. Form and function A Pythagorean cup looks like a normal drinking cup, except that the bowl has a central column in it, giving it a shape like a Bundt pan. The central column of the bowl is positioned directly over the stem of the cup and over a hole at the bottom of the stem. A small open pipe runs from this hole almost to the top of the central column, where there is an open chamber. The chamber is connected by a second pipe to the bottom of the central column, where a hole in the column exposes the pipe to (the contents of) the bowl of the cup. When the cup is filled, liquid rises through the second pipe up to the chamber at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chain Fountain
The chain fountain phenomenon, also known as the self-siphoning beads, or Newton's beads is a physical phenomenon observed with a chain placed inside a jar, when one end of the chain is pulled from the jar and is allowed to fall under the influence of gravity. This process establishes a self-sustaining flow of the chain which rises over the edge and goes down to the floor or ground beneath it, as if being sucked out of the jar by an invisible siphon. For chains with small adjacent beads, the arc can ascend into the air over and above the edge of the jar with a noticeable gap; this gap is greater when the chain falls further. History The self-siphoning phenomenon has been known for some time, and had become a topic of public discussion many times in the past. Science entertainer Steve Spangler presented this phenomenon on TV in 2009. This phenomenon is classically known as Newton's beads. The effect is most pronounced when using a long ball chain. The higher the jar containin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barometer
A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface troughs, pressure systems and frontal boundaries. Barometers and pressure altimeters (the most basic and common type of altimeter) are essentially the same instrument, but used for different purposes. An altimeter is intended to be used at different levels matching the corresponding atmospheric pressure to the altitude, while a barometer is kept at the same level and measures subtle pressure changes caused by weather and elements of weather. The average atmospheric pressure on the earth's surface varies between 940 and 1040 hPa (mbar). The average atmospheric pressure at sea level is 1013 hPa (mbar). Etymology The word '' barometer'' is derived from the Ancient Greek (), meaning "weight", and (), meaning "me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suction Pump
A vacuum pump is a device that draws gas molecules from a sealed volume in order to leave behind a partial vacuum. The job of a vacuum pump is to generate a relative vacuum within a capacity. The first vacuum pump was invented in 1650 by Otto von Guericke, and was preceded by the suction pump, which dates to antiquity. History Early pumps The predecessor to the vacuum pump was the suction pump. Dual-action suction pumps were found in the city of Pompeii. Arabic engineer Al-Jazari later described dual-action suction pumps as part of water-raising machines in the 13th century. He also said that a suction pump was used in siphons to discharge Greek fire. The suction pump later appeared in medieval Europe from the 15th century.Donald Routledge Hill (1996), ''A History of Engineering in Classical and Medieval Times'', Routledge, pp. 143 & 150-2Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", ''Scientific American'', May 1991, pp. 64-69 (cf. Donald Routle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Book Of Ingenious Devices
The ''Book of Ingenious Devices'' (Arabic: كتاب الحيل ''Kitab al-Hiyal'', Persian: كتاب ترفندها ''Ketab tarfandha'', literally: "The Book of Tricks") is a large illustrated work on mechanical devices, including automata, published in 850 by the three brothers of Persian descent, known as the Banu Musa (Ahmad, Muhammad and Hasan bin Musa ibn Shakir) working at the House of Wisdom (''Bayt al-Hikma'') in Baghdad, Iraq, under the Abbasid Caliphate. The book described about one hundred devices and how to use them. Overview The book was commissioned by the Abbasid Caliph of Baghdad, also made by Al-Jazari, Abu Jafar al-Ma'mun ibn Harun (786–833), who instructed the Banu Musa to acquire all of the Hellenistic texts that had been preserved by monasteries and by scholars during the decline and fall of Roman civilization. The Banū Mūsā brothers invented a number of automata (automatic machines) and mechanical devices, and they described a hundred such devices i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Pump
A vacuum pump is a device that draws gas molecules from a sealed volume in order to leave behind a partial vacuum. The job of a vacuum pump is to generate a relative vacuum within a capacity. The first vacuum pump was invented in 1650 by Otto von Guericke, and was preceded by the suction pump, which dates to antiquity. History Early pumps The predecessor to the vacuum pump was the suction pump. Dual-action suction pumps were found in the city of Pompeii. Arabic engineer Al-Jazari later described dual-action suction pumps as part of water-raising machines in the 13th century. He also said that a suction pump was used in siphons to discharge Greek fire. The suction pump later appeared in medieval Europe from the 15th century. Donald Routledge Hill (1996), ''A History of Engineering in Classical and Medieval Times'', Routledge, pp. 143 & 150-2 Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", ''Scientific American'', May 1991, pp. 64-69 ( cf. Donal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tensile Strength
Ultimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or F_\text within equations, is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials the ultimate tensile strength is close to the yield point, whereas in ductile materials the ultimate tensile strength can be higher. The ultimate tensile strength is usually found by performing a tensile test and recording the engineering stress versus strain. The highest point of the stress–strain curve is the ultimate tensile strength and has units of stress. The equivalent point for the case of compression, instead of tension, is called the compressive strength. Tensile strengths are rarely of any consequence in the design of ductile members, but they are important with brittle members. They are tabulated for common materials such as alloys, composite materials, ceramics, plastics, and wood. Definition The ultimate tensil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History
History (from Greek , ''historia'', meaning "inquiry; knowledge acquired by investigation") is the study and the documentation of the past. Events before the invention of writing systems are considered prehistory. "History" is an umbrella term comprising past events as well as the memory, discovery, collection, organization, presentation, and interpretation of these events. Historians seek knowledge of the past using historical sources such as written documents, oral accounts, art and material artifacts, and ecological markers. History is also an academic discipline which uses narrative to describe, examine, question, and analyze past events, and investigate their patterns of cause and effect. Historians often debate which narrative best explains an event, as well as the significance of different causes and effects. Historians also debate the nature of history as an end in itself, as well as its usefulness to give perspective on the problems of the present. Stories common to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blaise Pascal
Blaise Pascal ( , , ; ; 19 June 1623 – 19 August 1662) was a French mathematician, physicist, inventor, philosopher, and Catholic writer. He was a child prodigy who was educated by his father, a tax collector in Rouen. Pascal's earliest mathematical work was on conic sections; he wrote a significant treatise on the subject of projective geometry at the age of 16. He later corresponded with Pierre de Fermat on probability theory, strongly influencing the development of modern economics and social science. In 1642, while still a teenager, he started some pioneering work on calculating machines (called Pascal's calculators and later Pascalines), establishing him as one of the first two inventors of the mechanical calculator. Like his contemporary René Descartes, Pascal was also a pioneer in the natural and applied sciences. Pascal wrote in defense of the scientific method and produced several controversial results. He made important contributions to the study of fluids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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