This app is a educational game that simulate how to determine mass density of the object that dipped into the water. By the changing of water volume and mass of the object, we can calculate the mass density is egual to mass of the object devide by the volume of changing water. The changing volume of water actually is the volume of the object. So with read the changing water level scale, we will able to know the volume of object and calculate its mass. Let Try it and Have Fun!