Measuring the Wind

The wind can vary in a number of ways – both in terms of its speed and also its direction. As a result, different pieces of equipment are needed to measure these different characteristics.

Firstly we will consider how to measure the direction of the wind. For this, two main devices are used – a weather vane and a wind sock.

Weather Vanes

Weather vanes are one of the oldest of all weather instruments, working by swinging around in the wind to show which direction it is blowing from. Traditionally, weather vanes had a religious importance and appeared in the form of weathercocks on church roofs as early as the 9^th Century AD. The head of the cockerel would point into the wind, indicating the direction the wind was blowing from. Weather vanes now appear in a wide variety of forms and it is even possible to make your own. Keep an eye out for weather vanes and see how many different types you see. What is the most common shape for a weather vane – is it still the cockerel?

Wind Socks

Another device used to measure the wind is a wind sock. This instrument is found mainly at airports, seaports and other open areas such as mountain roads where a very visual indication of the wind is needed. Wind socks actually show both the direction and speed of the wind. The direction is shown when the wind blows into the open end and the sock points the way the wind is blowing. An indication of wind strength is given by the shape and movement of the wind sock. If it is flapping about gently the wind is only light, whereas if it sticks out in a straight line the wind is much stronger.  This information is very useful to people on both ships and planes, and sometimes to car drivers too.  If you want to discover more about wind socks, why not make one for yourself? 

Anemometer

The main instrument used to measure the speed of the wind is an anemometer. The little cups on this device catch the wind and spin round at different speeds according to the strength of the wind.  A recording device is used to count how many times they spin round in a given time. If you have ever seen an anemometer, you will have noticed that the cups spin round very fast in a strong breeze.  Why don’t you make your own to test this out for yourself?  Alternatively, you can have a a closer look at an anemometer in the Wind section of the Activities page.  There you'll be able to spin one for yourself!

Beaufort Scale

It is also possible to measure the speed of the wind by looking at its effects on the local environment.  In 1805, Admiral Francis Beaufort invented a scale of this type for measuring winds at sea by describing their effect on ships and waves.  His scale was later adapted for use on land, and the same system is still used by many weather stations today. Click here to find out more about the Beaufort Scale.

Hopefully you now know a bit more about wind and how to measure it.  The wind doesn't always blow at the same speed however, so it is also necessary to look at strong winds - which we know as hurricanes or tropical storms.  To find out more about these extreme events, let's go to the next section.