I recently had the opportunity to photograph the Materials Science and Engineering booth at Georgia Tech's Engineers Week fair. MSE was demonstrating several interesting properties of materials, including the low thermal conductivity of a space shuttle heat-shield tile, a methanol powered fuel cell, and the extreme expansion of nitrogen as it boils. In the photograph shown here, a superconductor is cooled with liquid nitrogen to below its critical temperature (the temperature below which it superconducts). When that happens, it generates a magnetic field stronger than gravity. Put a magnet on top and what do you get? Levitation.
