Homemade compass

We decided to build our own compass to help orient us for our stargazing. We magnetized a paperclip using our dangerously powerful- magnet (rubbing the paperclip across the magnet many times). We filled a container with water and put our now magnetized paperclip on a piece of cork in the water. The paperclip and cork slowly rotated until it was oriented north-south. We spun the cork around multiple times and it kept re-orienting itself. Pretty cool to see this invisible force at work (although next time I'll use a round piece of cork so it doesn't get stuck on the edge of the container without being able to turn). Jr. Scientist A liked the experiment, but I have a sense that the underlying concept of the earth having a magnetic field was a little too advanced.