"Freedom to live and to think about life for its own sake is important and even essential to a child. Since we can't know what knowledge will be most needed in the future, it is senseless to try to teach it in advance. Instead, we should try to turn out people who love learning so much and learn so well that they will be able to learn whatever needs to be learned." -John Holt.
Tuesday, November 16, 2010
Levitating Ping Pong Ball 10 November 2010
The air flows over a curved surface can stick to the surface and follow it, so the flow also becomes curved. When the ping pong ball sits in the centre of the air stream, the flow traps the ball by passing around it on all sides, sticking to its surface.