Overview

Today I start my experimental lectures. They are also lectures of anxiety because with the setting up of every experiment comes the feeling: Will it go according to plan? For the best preparations are by no means an absolute safeguard against nature's perversity. ^[1]

Heinrich Hertz

The legend goes that a new physics professor at a Midwest school wanted to impress the undergraduates with his teaching. ^[2] In his first semester, he requested to teach one of the large sections of freshman physics. Held in a huge lecture hall, each class period consisted of a lecture about a major topic and then a demonstration of a principle associated with that topic. For the class period that discussed motion in a plane, the new professor refused to use the six-foot air table that everyone else used. Instead, he had the technicians build him something twice as large. Likewise, for the class period on Newton's laws, he refused to use the tabletop spring balance that everyone else used; he had the technicians build him something much larger.

When the time came for him to demonstrate the motion of a pendulum, he put aside the tabletop pendulum that everyone else used and called for a hook to be mounted in the lecture hall's ceiling. Then he had tethered to the hook a medicine ball: one of those heavy leather balls that athletes in the 1950s tossed around for exercise. The medicine ball was fixed so that it could swing freely from...