| Columbia Encyclopedia: weather vane |
| WordNet: weather vane |
The noun has one meaning:
Meaning #1:
mechanical device attached to an elevated structure; rotates freely to show the direction of the wind
Synonyms: weathervane, vane, wind vane
| Wikipedia: Weather vane |
A weather vane is an instrument for showing the direction of the wind. They are typically used as an architectural ornament to the highest point of a building.
Although partly functional, weather vanes are generally decorative, often featuring the traditional cockerel design with letters indicating the points of the compass. Other common motifs include ships, arrows and horses. Not all weather vanes have pointers.
The word 'vane' comes from the Anglo-Saxon word 'fane' meaning 'flag'.
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The design of a weather vane is such that the weight is evenly distributed each side of the surface, but the surface area is unequally divided, so that the pointer can move freely on its axis. The side with the larger area is blown away from the wind direction. The pointer is therefore always on the smaller side (a north wind is one that blows from the north). Most weather vanes have directional markers beneath the arrow, aligned with the geographic directions.
Weather vanes, especially those with fanciful shapes, do not always show the real direction of a very gentle wind. This is because the figures do not achieve the necessary design balance: an unequal surface area but balanced in weight.
To obtain an accurate reading, the weather vane must be located well above the ground and away from buildings, trees, and other objects which interfere with the true wind direction. Changing wind direction can be meaningful when coordinated with other apparent sky conditions, enabling the user to make simple short range forecasts. From the street level the size of many weathercocks is deceptive. [1]
The Tower of the Winds on the ancient Roman agora in Athens once bore on its roof a wind vane in the form of a bronze Triton holding a rod in his outstretched hand, rotating as the wind changed direction. Below, the frieze was adorned with the eight wind deities. The eight metre high structure also featured sundials, and a water clock inside dates from around 50 BC.[2]
The wind van evolved from a Triton to a weathercock as the Roman Empire converted to Christianity. Many churches have a weathercock on the tower or spire. The cock refers to the fall of St Peter and to intimate the necessity for watchfulness and humility.
Early weather vanes had very ornamental pointers, but modern wind vanes are usually simple arrows that dispense with the directionals because the instrument is connected to a remote reading station. Modern aerovanes combine the directional vane with an anemometer (a device for measuring wind speed). Co-locating both instruments allows them to use the same axis (a vertical rod) and provides a coordinated readout.
Another wind direction device is the windsock used at airports to show wind direction and strength. The wind fills the sock and makes it blow away from the prevailing wind. Strong winds make the sock point almost horizontally, while light airs allow the sock to hang limply. Because of its size, the windsock can often be seen from the air as well as the ground. Even the most technologically-advanced airports still use windsocks.
According to the Guinness World Records, the world's largest weather vane is located in Jerez, Spain. A challenger for the title of world's largest weather vane is located in Whitehorse, Yukon. The weather vane is a retired Douglas DC-3 atop a swiveling support. Located beside Whitehorse International Airport, the weather vane is used mainly by pilots to determine wind direction. The weather vane only requires a 5 km/hour wind to rotate. [3]
The term "weathervane" is also a slang word for a politician who has frequent changes of opinion. The National Assembly of Quebec has banned use of this slang term as a slur after its use by members of the legislature.[4][5]
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![]() | Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/. Read more | |
![]() | WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. Read more | |
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