Hands-On Learning

The Center of Gravity Paradox seems to violate the rule stating the lower a system’s center of gravity the more stable it is. The device includes a 120cm aluminum rod with a sliding brass weight. Students can balance the rod on their fingertip and adjust the weight to different heights on the rod. Unexpectedly, they will discover the device is more stable when the mass is at a higher setting. Use their experiences as a springboard to discussing perceptions about the center of gravity and to introduce concepts of angular acceleration and moment of inertia.