<p>The Foucault pendulum is a highly educational experiment that provides a visible demonstration of Earth’s rotation—something difficult to perceive in everyday life. However, unlike the specially crafted Foucault pendulums exhibited in science museums, it is not easy for students to observe the precession caused by Earth’s rotation employing a simply constructed spherical pendulum made by themselves. Here, we theoretically explained that it was challenging because the precession of the spherical pendulum erased the precession caused by Earth’s rotation. We also supported this explanation by actual experimental data from our own simple pendulum. Moreover, based on this empirical and theoretical understanding, we focused on minimizing the initial angular velocity, the primary factor that makes it difficult to observe the Foucault pendulum’s precession, and successfully demonstrated Earth’s rotation. We hope that our investigation would help students carry out their own Foucault pendulum experiments and probe Earth’s rotation for themselves in a typical school setting without requiring any specialized equipment.</p>