gyroscopes

Did you use training wheels when you learned to ride a bicycle? My dad was convinced they slowed down the learning process and taught bad habits, so he just held on to the back of the seat and ran down the street with me while I pedaled. Then he let go and I fell over. Rinse knees, repeat, until I caught on to the trick of keeping my balance.

For a beautiful demonstration of both magnetic force and gyroscopic motion, let's contemplate the Levitron. This novelty toy (which even now sits on my shelf waiting for a quick spin around the block) consists of a magnetic base upon which you spin a magnetic gyroscope. Both the bottom of the gyroscope and the top of the base contain magnetic north poles, and therefore they repel each other.

However, try as you might, you'll never be able to balance the magnet above the base without spinning the top. Why is this?