How can scientists determine wind speed

A: Wind is caused by an air pressure change.  You can measure the velocity of the wind using a device called an anemometer. An anemometer looks like a weather vane but instead of measuring the way the wind blows with points, it has four cups so it can measure wind speed more accurately.

-SТОЯМ

we need the pie chart in order to

music and prayer? (you may punch me in the face if im wrong : > )