Sunday, January 1, 2012

Weathervanes: Whenever the Weather is Windy

Weather vanes may appear a simple decoration for the outside of your home but they can in fact a rather complicated piece of engineering. The very first recorded use of a weather vane as an instrument was in the 1500s and they have since become an English tradition decorating homes and boat harbours. Also called ‘wind vanes’, these instruments are attached to a roof or top of a building to calculate in which direction the wind is blowing and are particularly useful for sailors, farmers and hunters. Each device sits loosely on an axis and its weight is distributed evenly so that when the wind blows, it spins round and its arrow displays the direction the win blows. At the base of the vane the geographic north, south, east and west are displayed to make a reading easier. Placed high up (around 10 metres above ground level) and away from the obstruction of trees and buildings, a weather vane can give a very accurate reading.

For the average homeowner, the use of a weather vane might seem a little redundant. However, when the wind direction is read and compared with the type of clouds or the colour of the sky, a weather prediction can usually be made. For example, if you live in the Northern Hemisphere, the sky in the morning is red, the clouds are low and the wind is blowing south then a storm may be on its way.

A weather vane used as both a practical device and a decoration can boast a figurine on its axis, typically a cockerel and they are most commonly made from metal such as wrought iron, brass or copper. The main reason for a weather vane being crafted from such materials is that they are constantly subjected to all kinds of weather extremities and cannot afford to rot or fall apart. Other figurines placed on a weather vane include ships, eagles, foxes and simple arrows. Professionally designed and crafted wind vanes can be very aesthetically pleasing, for example when the sun reflects off a brass figurine and it spins when a light breeze passes by.

With some weathervanes it is also possible to calculate the wind speed. To do this the vane must has an ‘anemometer’ which comprises of four cups turned on their sides, or a windmill which spins round continuously. Counting how many turns the cups/windmill make(s) over a set amount of time produces an average wind speed. This is of course is quite a dated and complex method of finding out wind speed, and instead many wind vanes are connected to a reading station to find this information out.

Placing a weather vane on a house can not only provide a beautiful focal point for a boring slate roof, but also a fun and hands on means to teach young children the geographical directions and what the wind can tell you about the weather. Overall they are a great investment to brighten up your house whilst providing a practical use.

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