Previously, [Vinnie] had been stopping the clock every evening, and hoped he would remember to start the pendulum in motion 12 hours later. This was a chore, so he decided to automate the process.

That big grandfather clock in the library might be an impressive piece of mechanical ingenuity, and an even better example of fine cabinetry, but we’d expect that the accuracy of a pendulum ...

“It’s similar to how pendulum clocks hanging on the same wall eventually swing in unison. But in our case, it’s atoms ...

A watch differs from a clock In its having a vibrating wheel instead of a vibrating pendulum ; and, as in a clock, gravity is always pulling the pendulum down to the bottom of its arc, which is ...