"It's moving."
Murphy answered calmly, his gaze shifting to the slowly swinging pendulum bob.
Cecilia was stunned, her azure eyes widening slightly. "It's moving? It's really moving?"
Murphy pointed to the suspended pendulum bob. "This device... I call it a Foucault Pendulum. Look, the path of its swing is deflecting by a minuscule amount with each oscillation. If the earth were stationary, the plane of its swing should remain constant. But now..."
He gestured for Cecilia to observe the subtle changes on the dial. "This deflection proves my hypothesis."
He continued to explain in simple terms, "Imagine you're standing on a slowly rotating disk, swinging this weight. Even though you can't feel the rotation, the path of the swing will secretly change direction. What we are observing now is exactly that phenomenon."
Cecilia listened intently, her little face etched with contemplation.
She suddenly asked, "So the earth really is round?"
