In 1993, former president Jimmy Carter presented the commencement address to the graduating class at Rice University in Houston, Texas. He shared the story of a young college freshman who overslept for the final exam in geometry and pleaded for mercy from his professor. The professor granted it — sort of. "If you provide an accurate answer for one question, I will submit a passing grade for you." Without much choice, the student agreed. Here is the question: "If I give you a barometer, how can you use it to determine the height of this building?"

The student smiled, and then began, "Well there are several ways. I could tie the barometer to a rope, lower it from the roof to the ground, and measure the length of the rope. Or I could drop the barometer, time its fall, and divide that time by…