Wind

Wind is a current of air moving across the earth’s surface. Wind can blow from different directions and at different speeds. We use different instruments to measure wind direction and wind speed.

Wind direction refers to the direction the wind is coming from. For instance, an easterly wind is a wind that blows from the east. Wind direction is measured using a wind vane or a wind sock. Look at the pictures below.

This is a wind vane. As the wind blows, the arrow turns to show the direction that the wind is coming from.

This is a wind sock. As the wind blows, it turns to show the wind direction.

Wind speed refers to how fast the wind is blowing. It is measured using an anemometer. The picture below shows an anemometer.

When the wind blows, it makes the cups on top of the anemometer spin. The faster the wind blows, the faster it spins. The rate at which it spins is used to calculate wind speed.

In the video below you can see an anemometer and a wind vane working.