英语时差：为什么飞盘会飞？（上）

With a gentle flick of the wrist on a warm summer day, you can launch a frisbee on a long and graceful flight. Why frisbees fly so well? One reason is something called gyroscopic force. This is the tendency of a spinning object to maintain a stable orientation. If you throw any round object so it spins as it flies–a record album or compact disk for example–it will tend to fly something like a frisbee. If you throw it horizontally, it will stay horizontal for most of its flight. The leading edge of a CD or record is much narrower than its broad, flat surfaces, so this steady orientation helps reduce air friction.