Magnetic levitation is made possible by magnetic fields that are actively excluded from superconductors. If a small magnet is brought near a superconductor, it will be repelled because induced super currents will produce mirror images of each pole. If a small permanent magnet is placed above a superconductor, it can be levitated by this repulsive force.
One use of magnetic levitation in today's world is transportation. For example, it's possible to run a train on magnetic levitation, such as the Yamanashi mag-lev they are testing in Japan (see attached page). This train levitates nearly 4 inches above the guide ways, and can reach speeds of over 300 miles an hour.
One difficulty I encountered while building my mag-lev car was that it kept flipping over. I fixed this problem by adding weight on each of the back sides. However, this did not completely solve my problem, because now instead of flipping forward, it was going off to the side.
I fixed this problem by adding more weight on one side to even it out.
Doing this project, I learned about magnetic levitation, which I knew nothing about beforehand. I now know how magnets can be used in technology and make things like roller coasters and trains work.
I think I should get a passing grade on this project, because I made my mag-lev car work, and it made it all the way down the track. I also learned a lot by doing this project.