text: if you have the mass of an object, how can you find the volume? you don't know the denstiy, and you're measuring a liquid. the liquid has an unknown substance in it. given the mass, how can you find the volume of the liquid and the substance without having to use a graduated cylinder? you have to measure how much liquid the object displaces.  the volume of the displaced liquid equals the volume of the object.  you will need a graduated cylinder or some other device to measure liquid volume.