How Do Weathervanes Spin?

Placement

Weather aficionados place weather vanes on top of the highest available point of a building. Choosing an unobstructed position for the weather vane will help provide the most accurate reading of wind direction. Weather vanes are constructed of multiple parts. At the top, there is a balanced ornament with an arrow that rotates with the wind. The remaining parts below the ornament remain fixed to the rooftop. Some weather vanes include directional letters depicting the four directions of north, south, east and west. Directionals reside below the ornament on a rod and always remain in a fixed position. Above the directional lies a small globe-like ball that marks the point between the rotating and fixed portions of the weather vane. Below the directionals lies a larger globe ball centered around the rod. The rod is used for mounting the weather vane to the building.

Balance

Weather vanes will not work properly without proper balancing of all the elements of the vane. The entire fixed rod and directionals must be leveled and securely mounted. The ornament should be balanced properly in relation to the rod and directional. This ornament should be sturdy enough to resist the weather but light enough to rotate freely with the wind. A weather vane's basic design requires a larger surface area on the back portion of the weather vane to catch the wind. Since the arrow side of the vane has a smaller surface area, it stops spinning to point into the wind. Imagine a standard weather vane with a scrolled, ornamental arrow. The bulk of the design exists on one side of the rod with the lighter arrow point on the other.

Wind

Weather vanes function to denote the direction of the wind. This information is helpful to sailors as well as anyone who watches the wind as an indicator of weather changes. For the most part, weather vanes now function solely as a decorative feature on churches, homes and gazebos. When placed well above obstructions and free to catch the wind, a weather vane will rotate with the arrow pointing to the wind direction. This occurs because there is unequal balance between the larger portion of the arrow and the fine-tooled point. The wind grabs the larger portion of the vane, turning it to the proper direction.