Weather vanes have arrows that point in the direction that wind is coming from, and this is achieved through differing surface areas on either side of the arrow. Discover how wind pushes the large surface area side of a weather vane around with help from a science teacher and field biologist in this free video on weather.
Hi, I'm Brian with ericksontutoring.blogspot.com and today we're going to discuss how a weathervane works. So weathervanes measure the wind direction. The pretty easy process to explain and I think it should be a fairly easy concept. So weathervanes contain an arrow or some sort of device that's going to point in the direction and there's two main features of these arrow. First, the weight is evenly distributed on each side of this central axis and that allows for a even rotation of your arrow. The second main feature is that, there's a difference in the surface area between the two sides. There's one side that has low surface area and another side, the end to the arrow or some other feature that usually has a lot larger surface area. When the wind blows, it catches this large surface area and pushes it until the large surface area is directly in the path of the wind and your arrow is pointing towards the direction of the wind that's coming from. And then all you have to do is you read the direction that your small arrow is pointing at and that's the wind direction. So that's how a weathervane works. Basically the wind just pushes the large surface area side around until it can't push it anymore.