A spinning top, or simply a top, is a toy with a squat body and a sharp point at the bottom, designed to be spun on its vertical axis, balancing on the tip due to the gyroscopic effect.
Once set in motion, a top will usually 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 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 into games or for divination and ritual purposes.
The ubiquity of spinning tops lends to the fact that the toy is used to name many living things such as Cyclosa turbinata, whose name comes from the Latin roots for spinning top.
History
Origins
Spinning tops emerged independently in various cultures worldwide and are considered among the oldest known toys discovered by archaeologists. They have been unearthed on every continent except Antarctica. For instance, tops dating back to around 1250 BCE were found in China, while a carved wooden top from approximately 2000 BCE was discovered in Tutankhamun's tomb. Tops were used as toys in ancient Rome.
Besides toys, tops have also historically been used for gambling and prophecy. Some role-playing games use tops to augment dice in generating randomized results; it is in this case referred to as a spinner.
Gould mentions maple seeds, celts (leading to rattlebacks), the fire-drill, the spindle whorl, and the potter's wheel as possible predecessors to the top, which he assumes was invented or discovered multiple times in multiple places.
Color demonstrations with tops
A top may be used to demonstrate visual properties, such as by James David Forbes and James Clerk Maxwell in Maxwell's disc (see color triangle). By rapidly spinning the top, Forbes created the illusion of a single color that was a mixture of the primaries:
[The] experiments of Professor J. D. Forbes, which I witnessed in 1849… [established] that blue and yellow do not make green, but a pinkish tint, when neither prevails in the combination…[and the] result of mixing yellow and blue was, I believe, not previously known.
— James Clerk Maxwell, Experiments on colour, as perceived by the eye, with remarks on colour-blindness (1855), Transactions of the Royal Society of Edinburgh
Maxwell took this a step further by using a circular scale around the rim with which to measure the ratios of the primaries, choosing vermilion, emerald, and ultramarine.
Spinning methods
Finger twirling
Smaller tops have a short stem, and are set in motion by twirling it using the fingers. A thumbtack may also be made to spin on its tip in the same way.
Strings and whips
A typical fist-sized model, traditionally made of wood with a blunt iron tip, is meant to be set in motion by briskly pulling a string or rope tightly coiled around the body. The rope is best wound starting near the tip and progressing up along the widening body, so that the tension of the string will remain roughly constant while the top's angular speed increases.
These tops may be thrown forward while firmly grasping the end of the string and pulling it back. The forward momentum of the top contributes to the string's tension and thus to the final spin rate.
In some throwing styles, the top is thrown upside-down, but the first loop of the rope is wound around a stubby "head". Then, the sudden yank on the head as the string finishes unwinding causes the spinning top to flip over and land on its tip.
Alternatively, tops of this class may be started by hand but then accelerated and kept in motion by striking them repeatedly with a small whip.
Augers
Some larger models are set in motion by means of a built-in metal auger (spiral plunger). In these models, the actual top may be enclosed in a hollow metal shell, with the same axis but decoupled from it; so that the toy may appear to be stationary but "magically" balanced on its tip.
Magnetic fields
Some modern tops are kept perpetually in motion by spinning magnetic fields from a special ground plate.
Notable types
wikipedia, wiki, encyclopedia, book, library, article, read, free download, Information about Spinning top, What is Spinning top? What does Spinning top mean?