The wind is the movement of air between regions having different pressure. The temperature difference between the regions causes pressure difference, which allows the flow of wind. The rotation of the earth also affects the direction of the wind because of the Coriolis force. The wind has a significant role in determining the weather of a region. In science, we measure every significant factor and evaluate it to our own use. Thus, we measure the speed of the wind and its direction. Anemometer is a device to measure the speed of the wind. A wind vane is a device that measures the direction of the flow of wind. We also call it weather vane. Let us study about how does this wind vane works?
History of Wind Vane
We are using wind vane since ancient times. They are the grace of old buildings and Cathedrals. They are one of the old instruments used to predict the weather. Britishers and germans use it to show archers the direction of the wind. Greek astronomer Andronicus built the first wind vane for the tower of winds in Athens. It is made of bronze.
Components of a Wind Vane
Wind vane has a rotating ornament that points the direction at the top of the rod. It consists of a small globe at the top of the rod and a bigger one at the bottom of the rod. A direction pointer that indicates north, South, East, West is fixed to the rod between the two globes.
Constructing a Wind Vane
The design is made to allow free movement about the vertical axis. The pointer must have an unequal surface area, this will allow the smaller area to turn according to the wind. Distribute the weight equally on both sides of the axis. This will rotate the wind vane freely. The arrow point to the direction from which wind is coming. The proper directional markers allow the observer to identify the direction easily.
We should position the wind vane high enough to avoid wind interference from objects, buildings, and trees. We can station them at the top of the tower or poles that are on the roof of a building. We have to choose the highest point for the device.
Working of Wind Vane
A wind vane always points in the direction from which wind is coming. If the wind is flowing from East, the arrow will point to the east. We can predict some weather changes with the wind direction, like – If the device rotates from West to East, this indicates that pressure is low and stormy weather is overhead.
If direction changes from south to south-west, we can predict that warmer air is coming. If the wind vane starts fluctuating, this means the wind is unstable and current weather is about to change.
Types of Wind Vane
a) Classical style – It is very simple in design. Nowadays it is a decorative element in buildings and towers. The classical style has fin in the shape of a roaster.
b) Windsock – We can see these types of wind vanes in airports, near runways. While a windsock determines the direction it generally did not give the exact north, East, West, South direction.
Based on the inflation of the sock, the observer can estimate the strength of the wind. When landing or takeoff this is very helpful for the pilots. We can see a windsock at the golf course, marine, baseball field, where wind direction and strength is useful for the activity.
c) Digital wind vane – A digital wind vane is just more sophisticated. We can see them in weather stations, which measures temperature, pressure, and humidity with the direction and strength of the wind. It has an optical sensor that allows the processor to know the directions up to 16 positions. This reading is seen on a digital display.
Questions for Wind Vane
Q- What are the benefits of having a Wind Vane?
Ans – A wind vane can determine if a storm is coming towards you or moving away. This will give you extra time to ensure your safety. You can make advance preparation for the safety of your property. They are very helpful in activities like golf and boat sailing. As we know wind direction affects the direction of ocean currents hence fish catchers use the device for their benefits.