The colouless solid in the beaker is a cube of ice. If ice is less dense than water, how is it that the ice cube is floating mid-way of the liquid solution?

Answer: The pink liquid layer is water, and ice floats on water. However the colorless liquid layer is tupentine. It is insoluble in water, and has a density of 0.828 g per cubic centimeter. While the density of ice is 0.9g/cm³. Thus ice would sink in turpentine. In the beaker, water is the densest substance, followed by ice which is floating on the pink-coloured water, then colourless turpentine on the top layer.