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Spinning Top
A spinning top, or simply a top, is a toy with a squat body and a sharp point at the bottom, designed to be rotation, spun on its vertical Axis of rotation, axis, balancing on the tip due to the gyroscopic effect. Once set in motion, a top will usually precession, wobble for a few seconds, spin upright for a while, then start to wobble again with increasing amplitude as it loses energy, and finally tip over and roll on its side. Tops exist in many variations and materials, chiefly wood, metal, and plastic, often with a metal tip. They may be set in motion by twirling a handle with the fingers, by pulling a rope coiled around the body, or through a built-in auger (spiral plunger). Such toys have been used since Classical antiquity, antiquity in solitary or competitive games, where each player tries to keep one's top spinning for as long as possible or achieve some other goal. Some tops have faceted bodies with symbols or inscriptions, and are used like dice to inject randomness ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Tough Gang Of Spinning Tops
A, or a, is the first Letter (alphabet), letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is ''English alphabet#Letter names, a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, ''English articles, a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tutankhamun's Tomb
The tomb of Tutankhamun (reigned ), a pharaoh of the Eighteenth Dynasty of ancient Egypt, is located in the Valley of the Kings. The tomb, also known by its tomb number KV62, consists of four chambers and an entrance staircase and corridor. It is smaller and less extensively decorated than other Egyptian royal tombs of its time, and it probably originated as a tomb for a non-royal individual that was adapted for Tutankhamun's use after his premature death. Like other pharaohs, Tutankhamun was buried with a wide variety of funerary objects and personal possessions, such as coffins, furniture, clothing and jewelry, though in the unusually limited space these goods had to be densely packed. Robbers entered the tomb twice in the years immediately following the burial, but Tutankhamun's mummy and most of the burial goods remained intact. The tomb's low position, dug into the floor of the valley, allowed its entrance to be hidden by debris deposited by flooding and tomb construction. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician who was responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and light as different manifestations of the same phenomenon. Maxwell's equations for electromagnetism achieved the Unification (physics)#Unification of magnetism, electricity, light and related radiation, second great unification in physics, where Unification (physics)#Unification of gravity and astronomy, the first one had been realised by Isaac Newton. Maxwell was also key in the creation of statistical mechanics. With the publication of "A Dynamical Theory of the Electromagnetic Field" in 1865, Maxwell demonstrated that electric force, electric and magnetic fields travel through space as waves moving at the speed of light. He proposed that light is an undulation in the same medium that is the cause of electric and magnetic phenomena. (Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James David Forbes
James David Forbes (1809–1868) was a Scottish physicist and glaciologist who worked extensively on the conduction of heat and seismology. Forbes was a resident of Edinburgh for most of his life, educated at its University and a professor there from 1833 until he became principal of the United College of St Andrews in 1859. Life and work Forbes was born on 20 April 1809 at 86 George Street in Edinburgh, the fourth son of Sir William Forbes, 7th Baronet, of Monymusk and Pitsligo (1773–1828) and Williamina Belches of Invermay. His brothers were the advocate and agriculturalist Sir John Stuart Hepburn Forbes of Fettercairn and Pitsligo and the banker Charles Forbes. He entered the University of Edinburgh in 1825, and soon afterwards began to contribute papers to the ''Edinburgh Philosophical Journal'' anonymously under the signature "Δ". At the age of nineteen he became a fellow of the Royal Society of Edinburgh, and in 1832 he was elected to the Royal Society of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potter's Wheel
In pottery, a potter's wheel is a machine used in the shaping (known as throwing) of clay into round ceramic ware. The wheel may also be used during the process of trimming excess clay from leather-hard dried ware that is stiff but malleable, and for applying incised decoration or rings of colour. Use of the potter's wheel became widespread throughout the Old World but was unknown in the Pre-Columbian New World, where pottery was handmade by methods that included coiling and beating. A potter's wheel may occasionally be referred to as a "potter's lathe". However, that term is better used for another kind of machine that is used for a different shaping process, turning, similar to that used for shaping of metal and wooden articles. The pottery wheel is an important component to create arts and craft products. The techniques of jiggering and jolleying can be seen as extensions of the potter's wheel: in jiggering, a shaped tool is slowly brought down onto the plastic clay bod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spindle Whorl
A spindle whorl is a weighted object fitted to a spindle to help maintain the spindle's speed of rotation while spinning yarn. History A spindle whorl may be a disk or spherical object. It is typically positioned on the bottom of the spindle. The spinner spins the weighted spindle pulling off a mass of fibers which is twisted into yarn. Historically, whorls have been made of materials like amber, antler, bone, ceramic, coral, glass, stone, metal (iron, lead, lead alloy), and wood ( oak). Local sourced materials have been also used, such as chalk, limestone, mudstone, sandstone, slate, lydite and soapstone. Natufian artifacts unearthed in Israel at Nahal Ein Gev II, an archeological site, are believed to be the oldest spindle whorls found to date. Archaeologists say the perforated pebbles found scattered at the village site are 12,000 years old. According to scans of the pebbles, the perforations were biconical in shape and drilled in two directions, creating an hourgl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow Drill
A bow drill is a simple hand-operated type of tool, consisting of a rod (the ''spindle'' or ''drill shaft'') that is set in rapid rotary motion by means of a cord wrapped around it, kept taut by a bow and arrow, bow which is pushed back and forth with one hand. This tool of prehistoric origin has been used both as a drill, to make holes on solid materials such as wood, stone, bone, or teeth, and as a fire drill (tool), fire drill to Fire making#Friction, start a fire. The spindle can be held into a fixed frame, or by a hand-held block (the ''hand piece'' or ''thimble'') with a hole into which the top of the shaft is inserted. Some lubricant should be used to reduce friction between these two parts, otherwise, it could lead to some trouble when doing it too fast. A popular campcraft book of 1920 attributed this invention to the Inuit. In Mehrgarh (Pakistan) it has been dated between the 4th-5th millennium BCE. The string of the bow is wrapped once around the spindle, so that it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rattleback
A rattleback is a semi-ellipsoidal top which will rotate on its axis in a preferred direction. If spun in the opposite direction, it becomes unstable, "rattles" to a stop and reverses its spin to the preferred direction. For most rattlebacks the motion will happen when the rattleback is spun in one direction, but not when spun in the other. Some exceptional rattlebacks will reverse when spun in either direction. This counterintuitive behavior makes the rattleback a physical curiosity that has excited human imagination since prehistoric times. A rattleback may also be known as a "anagyre", "(rebellious) celt", "Celtic stone", "druid stone", "rattlerock", "Robinson Reverser", "spin bar", "wobble stone" (or "wobblestone") and by product names including "ARK", "Bizzaro Swirl", "Space Pet" and "Space Toy". History Archeologists who investigated ancient Celtic and Egyptian sites in the 19th century found celts which exhibited the spin-reversal motion. The antiquarian word ''celt'' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celt (tool)
In archaeology, a celt is a long, thin, prehistoric, stone or bronze tool similar to an adze, hoe, or axe. A shoe-last celt was a polished stone tool used during the early European Neolithic for felling trees and woodworking. Etymology The term "celt" seems to have come about from a copyist's error in many medieval manuscript copies of Job 19:24 in the Latin Vulgate Bible, which became enshrined in the authoritative Sixto-Clementine printed edition of 1592. Where all earlier versions (the Codex Amiatinus, for example) have ''vel certe'' (the Latin for 'but surely'), the Sixto-Clementine has ''vel celte''. The Hebrew has לעד (''lā‘aḏ'') at this point, which means 'forever'. The editors of the Oxford English Dictionary " nclineto the belief that ''celtis'' was a phantom word", simply a misspelling of ''certe''. However, some scholars over the years have treated ''celtis'' as a real Latin word. From the context of Job 19:24 ("Oh, that my words were inscribed with an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samara (fruit)
A samara (, ) is a winged achene, a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a Simple fruit, simple dry fruits, dry fruit, and is Dehiscence (botany), indehiscent (not Dehiscence (botany), opening along a seam). The shape of a samara enables the wind to carry the seed further away from the tree than regular seeds would go, and is thus a form of anemochory. In some cases the seed is in the centre of the wing, as in the elms (genus ''Ulmus''), the hoptree (''Ptelea trifoliata''), and the bushwillows (genus ''Combretum''). In other cases the seed is on one side, with the wing extending to the other side, making the seed autorotation (helicopter), autorotate as it falls, as in the maples (genus ''Acer (plant), Acer'') and ash trees (genus ''Fraxinus''). There are also single-wing samara such as mahogany (genus Swietenia) which have a shape that enables fluttering. Some species that normally produce paired samaras, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maple
''Acer'' is a genus of trees and shrubs commonly known as maples. The genus is placed in the soapberry family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated since http://www.mobot.org/MOBOT/research/APweb/. There are approximately 132 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America. Only one species, '' Acer laurinum'', extends to the Southern Hemisphere.Gibbs, D. & Chen, Y. (2009The Red List of Maples Botanic Gardens Conservation International (BGCI) The type species of the genus is the sycamore maple ''Acer pseudoplatanus'', one of the most common maple species in Europe.van Gelderen, C. J. & van Gelderen, D. M. (1999). '' Maples for Gardens: A Color Encyclopedia'' Most maples usually have easily identifiable palmate leaves (with a few exceptions, such as '' Acer carpinifolium'', '' Acer laurinum'', and '' Acer negundo'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Role-playing Game
A role-playing game (sometimes spelled roleplaying game, or abbreviated as RPG) is a game in which players assume the roles of player character, characters in a fictional Setting (narrative), setting. Players take responsibility for acting out these roles within a narrative, either through literal acting or through a process of structured decision-making regarding character development. Actions taken within many games succeed or fail according to a formal role-playing game system, system of rules and guidelines. There are several forms of role-playing games. The original form, sometimes called the tabletop role-playing game (TRPG or TTRPG), is conducted through discussion, whereas in live action role-playing game, live action role-playing (LARP), players physically perform their characters' actions.(Tychsen et al. 2006:255) "LARPs can be viewed as forming a distinct category of RPG because of two unique features: (a) The players physically embody their characters, and (b) the g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
