This lecture covers the Foucault pendulum, focusing on its movement on Earth's surface under the Coriolis effect. It explains the oscillation of the pendulum and its behavior in different reference frames, emphasizing the formalism of moving frames of reference and spherical coordinates. The lecture delves into the equations of motion, Newton's laws, and the expression of coordinates in spherical systems. It also discusses the importance of considering the Earth's rotation and the stationary nature of the reference frame. The lecture concludes with the analysis of the pendulum's movement and energy conservation in different scenarios.