Weather vane
From Wikipedia, the free encyclopedia
A weather vane, also known as a wind vane or weathercock, is an instrument for showing the direction of the wind. Although partly functional, weather vanes are generally decorative, often featuring the traditional cockerel design with letters indicating the points of the compass. Ships, arrows and horses are other common motifs, and not all have pointers. They are typically used as an architectural ornament to the highest point of a building.
The word 'vane' comes from the Anglo-Saxon word 'fane' meaning 'flag'.
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[edit] Operation
The design of a weather vane is such that the weight is evenly distributed each side of the axis of rotation, 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 pointer, 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]
[edit] History
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 vane 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.
[edit] Modern wind vanes
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]
[edit] Slang term
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]
[edit] See also
[edit] References
- ^ Eric R. Delderfield: "Ancient Churches for Beginners" Exmouth, Devon, The Raleigh Press,pp 42
- ^ Joseph V. Noble; Derek J. de Solla Price: The Water Clock in the Tower of the Winds, American Journal of Archaeology, Vol. 72, No. 4 (1968), pp. 345-355 (353)
- ^ DC-3 CF-CPY: The World's Largest Weather Vane - ExploreNorth
- ^ [1][dead link]
- ^ Quebec bans 'weathervane' insult | Metro.co.uk
[edit] Further reading
- A.B & W.T. Westervelt, American Antique Weather Vanes: The Complete Illustrated Westervelt Catalog of 1883. New York: Dover, 1982
- American Folk Art from the Shelburne Museum in Vermont (Catalog of the) Albright-knox Art Gallery,. Buffalo, NY, 1965 pp.20, 23-28
- Bishop, Robert Charles, A Gallery of American Weather Vanes and Whirligigs, New York: Dutton, 1981 or New York: Bonanza Books, Distributed by Crown, 1984, c.1981
- Buchert, Ilse., Weathercocks and Weather Creatures: some examples of early American folk art from the collection of the Shelburne Museum. Newport R.I., Third & Elm Press, 1970
- Burnell, Marcia, Heritage Above, A Tribute to Maine's Tradition of Weather Vanes, Down East Books, Camden Maine, 1991
- Coolidge, John T.,Weather Vanities, Milton, MA, 1978
- Crepeau, Pierre, Pointing at the Wind: The Weather Vane Collection of the Canadian Museum of Civilization, Hull, Canadian Museum c. 1990
- Fitzgerald, Ken, Weather Vanes and Whirligigs, New York: Clarkson n. Potter, 1967
- Geismar, Tom & Kahn, Harvey, Spiritually Moving: A Collection of American Folk Art Sculpture, New York: Hacker Art Books, 1998
- Kaye, Myrna, Yankee Weather Vanes, New York, Dutton, 1975
- Kennedy Quarterly, Volume XVI, Number 1, 18th and 19th Century Naive Art, New York: Kennedy Galleries, Inc. 1978
- Kenneth Lynch & Sons, Weather Vanes, Canterbury, Conn, Canterbury Pub. Co., c1971, series title: Architectural handbook series
- Klamkin, Charles, Weather Vanes: The History, Design and Manufacture of an American Folk Art, New York, Hawthorn Books, 1973
- Messent, Claude John Wilson, The Weather Vanes of Norfolk & Norwich, Norwich, Fletcher & son, limited, 1937
- Miller, Steve, The Art of the Weather Vane, Schiffer Publishing, Exton Penn.1984
- Mockridge, Patricia, Weather Vanes of Great Britain, London: R. Hale, 1990
- Needham, Albert, English Weather Vanes, These Stories and Legends from Medieval to Modern Times. Haywards Heath, Sussex, C. Clarke, 1953
- Reaveley, Mabel E., Weather Vane Secrets, Westford, MA. 1984
- Whirligigs & Weather Vanes: Contemporary Sculpture Whirligigs & Weather Vanes: Contemporary Sculpture. Eugene OR: Visual Arts Resources 1994
[edit] External links
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Wikimedia Commons has media related to: Weather vane |
- Home made electronic wind vane
- New Hampshire State %Percent for Art Commissioned Weathervanes by William Barth Osmundsen
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