A no cost method for finding the density of liquids

In this article, a simple and no cost method, which is based on Archimedes’ principle and moment of force and which does not require measurement of mass and volume of the liquid, is described for the determination of the density of liquids. The experimental set up for this purpose is very simple. A meter scale is hung by a string from a rigid support at center point. A solid substance of unknown mass is hung from the left side of the meter scale with a string and to balance the system, another solid body of unknown mass is hung from a string at the right side of the scale. The balancing length is measured. A beaker containing a liquid of known density is placed underneath the mass at right side of the scale such that it is immersed completely in the liquid. Due to upthrust the weight of the mass decreases and to make the system in balance it is moved to another point and the balancing length is measured. Now that mass is immersed completely in another liquid whose density is to be determined. The new balancing length is measured. From these three balancing length the density of the unknown liquid can be found out.