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Rattleback In Action
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. This spin-reversal appears to violate the law of the conservation of angular momentum. Moreover, 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 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 w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artifact (archaeology)
An artifact, or artefact (see American and British English spelling differences), is a general term for an item made or given shape by humans, such as a tool or a work of art, especially an object of archaeological interest. In archaeology, the word has become a term of particular nuance and is defined as an object recovered by archaeological endeavor, which may be a cultural artifact having cultural interest. Artifact is the general term used in archaeology, while in museums the equivalent general term is normally "object", and in art history perhaps artwork or a more specific term such as "carving". The same item may be called all or any of these in different contexts, and more specific terms will be used when talking about individual objects, or groups of similar ones. Artifacts exist in many different forms and can sometimes be confused with ecofacts and features; all three of these can sometimes be found together at archaeological sites. They can also exist in differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Articles Containing Video Clips
Article often refers to: * Article (grammar), a grammatical element used to indicate definiteness or indefiniteness * Article (publishing), a piece of nonfictional prose that is an independent part of a publication Article may also refer to: Government and law * Article (European Union), articles of treaties of the European Union * Articles of association, the regulations governing a company, used in India, the UK and other countries * Articles of clerkship, the contract accepted to become an articled clerk * Articles of Confederation, the predecessor to the current United States Constitution * Article of Impeachment, a formal document and charge used for impeachment in the United States * Articles of incorporation, for corporations, U.S. equivalent of articles of association * Articles of organization, for limited liability organizations, a U.S. equivalent of articles of association Other uses * Article, an HTML element, delimited by the tags and * Article of clothing, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Educational Toys
Educational toys (sometimes also called "instructive toys") are objects of play, generally designed for children, which are expected to stimulate learning. They are often intended to meet an educational purpose such as helping a child develop a particular skill or teaching a child about a particular subject. They often simplify, miniaturize, or even model activities and objects used by adults. Although children are constantly interacting with and learning about the world, many of the objects they interact with and learn from are not toys. Toys are generally considered to be specifically built for children's use. A child might play with and learn from a rock or a stick, but it would not be considered an educational toy because 1) it is a natural object, not a designed one, and 2) it has no expected educational purpose. The difference lies in perception or reality of the toy's intention and value. An educational toy is expected to educate. It is expected to instruct, promo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Novelty Items
Novelty (derived from Latin word ''novus'' for "new") is the quality of being new, or following from that, of being striking, original or unusual. Novelty may be the shared experience of a new cultural phenomenon or the subjective perception of an individual. From the meaning of being unusual usage is derived the concept of the novelty dance (a type of dance that is popular for being unusual or humorous); the novelty song (a musical item that capitalizes on something new, unusual, or a current fad); the novelty show (a competition or display in which exhibits or specimens are in way some novel); and novelty architecture (a building or other structure that is interesting because it has an amusing design). It is also this sense that applies to a novelty item, a small manufactured adornment, toy or collectible. These, in turn are often used as promotional merchandise in marketing. The chess term, novelty, is used for a move in chess which has never been played before in a recorded ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wooden Toys
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or woodchips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traditional Toys
A tradition is a belief or behavior (folk custom) passed down within a group or society with symbolic meaning or special significance with origins in the past. A component of cultural expressions and folklore, common examples include holidays or impractical but socially meaningful clothes (like lawyers' wigs or military officers' spurs), but the idea has also been applied to social norms such as greetings. Traditions can persist and evolve for thousands of years—the word ''tradition'' itself derives from the Latin ''tradere'' literally meaning to transmit, to hand over, to give for safekeeping. While it is commonly assumed that traditions have an ancient history, many traditions have been invented on purpose, whether that be political or cultural, over short periods of time. Various academic disciplines also use the word in a variety of ways. The phrase "according to tradition", or "by tradition", usually means that whatever information follows is known only by oral traditi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puzzles
A puzzle is a game, problem, or toy that tests a person's ingenuity or knowledge. In a puzzle, the solver is expected to put pieces together ( or take them apart) in a logical way, in order to arrive at the correct or fun solution of the puzzle. There are different genres of puzzles, such as crossword puzzles, word-search puzzles, number puzzles, relational puzzles, and logic puzzles. The academic study of puzzles is called enigmatology. Puzzles are often created to be a form of entertainment but they can also arise from serious mathematical or logical problems. In such cases, their solution may be a significant contribution to mathematical research. Etymology The ''Oxford English Dictionary'' dates the word ''puzzle'' (as a verb) to the end of the 16th century. Its earliest use documented in the ''OED'' was in a book titled ''The Voyage of Robert Dudley...to the West Indies, 1594–95, narrated by Capt. Wyatt, by himself, and by Abram Kendall, master'' (published circa 1595). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flinn Scientific Inc
{{disambiguation ...
Flinn may refer to: * Flinn (surname), of Irish origin *Flinn, Mississippi * Flinn, West Virginia *Flinn Township, Lawrence County, Indiana, dissolved in 1911 See also *Kelly Flinn incident * Flin, commune in Meurthe-et-Moselle department in France * Flynn (surname) *Flynn (other) Flynn is a surname or first name of Irish origin. Flynn may also refer to: Places Australia * Flynn, Australian Capital Territory, a suburb in the Canberra district of Belconnen * Division of Flynn, an Australian Electoral Division in the state of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tennis Racket Theorem
The tennis racket theorem or intermediate axis theorem is a result in classical mechanics describing the movement of a rigid body with three distinct principal moments of inertia. It is also dubbed the Dzhanibekov effect, after Soviet cosmonaut Vladimir Dzhanibekov who noticed one of the theorem's logical consequences while in space in 1985, although the effect was already known for at least 150 years before that and was included in a book by Louis Poinsot in 1834. The theorem describes the following effect: rotation of an object around its first and third principal axes is stable, while rotation around its second principal axis (or intermediate axis) is not. This can be demonstrated with the following experiment: hold a tennis racket at its handle, with its face being horizontal, and try to throw it in the air so that it will perform a full rotation around the horizontal axis perpendicular to the handle, and try to catch the handle. In almost all cases, during that rotati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tesla's Egg Of Columbus
Tesla's Egg of Columbus was a device exhibited in the Westinghouse Electric display at the 1893 Chicago World's Columbian Exposition to explain the rotating magnetic field that drove the new alternating current induction motors designed by inventor Nikola Tesla by using that magnetic field to spin a copper egg on end. Origins At the 1893 World's Columbian Exposition Westinghouse Electric (who had a large space in the "Electricity Building" devoted to their electrical exhibits) asked Tesla to participate and gave his devices their own exhibit space. The display demonstrated a series of electrical effects related to alternating current, AC generators, and displayed many types of induction motors and explained the rotating magnetic field that drove them. With the fair celebrating the 400th anniversary of Christopher Columbus's arrival in the New World, the "Egg of Columbus" exhibit, building on the apocryphal 15th century story of the " Egg of Columbus" (where the explorer sto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spoon Celt
A spoon is a utensil consisting of a shallow bowl (also known as a head), oval or round, at the end of a handle. A type of cutlery (sometimes called flatware in the United States), especially as part of a place setting, it is used primarily for transferring food to the mouth. Spoons are also used in food preparation to measure, mix, stir and toss ingredients and for serving food. Present day spoons are made from metal (notably flat silver or silverware, plated or solid), wood, porcelain or plastic. There are a wide variety of spoons that are made of a variety of materials and by different cultures for many different uses and foods. Terminology The spoon consists of a ''bowl'' and a handle. A handle in a shape of a slender stick is frequently called a ''stem''. The stem can end in a sharp point or be crowned with a ''knop'', a decorative knob. The ''knop-top'' spoons with a variety of knop shapes described by colorful terms like "acorn", "writhen-end" (spiral ornament on a bal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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