These determine wind direction. They are often made with a simple arrow design on a rotating axis that points into the wind.
To understand wind, we must measure its speed and direction using specific instruments: get wind
These measure wind speed. You can build a DIY version using paper cups, straws, and a pencil. As the wind blows, the cups spin, and the rotations per minute can be calculated to determine speed. These determine wind direction
"Getting" wind can also mean converting its kinetic energy into mechanical or electrical power: Make Your Own Wind Chime - Super Simple the cups spin