John Gleaves, Ph.D., associate professor of chemical engineering, sits at a makeshift desk in his Urbauer Hall office, victim of a wicked April Fool’s joke perpetrated by his graduate students. Gleaves walked into his office the morning of April 1 to find it filled with balloons. The sign over his left shoulder asks: “Can you Knudsen diffuse your way to your desk?” Knudsen diffusion is the process that governs the movement of molecules in catalysis experiments that Gleaves and his students perform. In a Knudsen pulse response experiment, molecules move randomly and independent of one another through a packed bed of solid particles. The hundreds of balloons his students filled represent a packed bed. Eventually Gleaves played the role of a molecule and made his way to his computer. By the way, his office is now back to normal, he reports.