Purpose:Demonstrate buoyancy with a counterintuitive element.
Description:A ball floats in a beaker of water (at left in picture above). The ball sinks in a beaker of mineral spirit paint thinner (at right above). The mineral spirit paint thinner is immiscible with water, and will float above the water when poured slowly on top of water. The ball then floats at a higher level because the mineral spirits in which the upper part of the ball is floating provide an additional buoyant force on the ball. If the ball is floating on water alone, the top part of the ball is immersed in air, which has a much smaller density.