How to Measure Density of Floating Object


When we dip a mug in water, a significant volume of water is displaced by it while entering the water and a significant rise in the level of water is observed because of this. If we subtract both the values, we can easily find the values or specifications related with it but if the case is of a floating object and if we are asked to find its density, we get puzzled. In order to measure the density of a floating object, we need to use our brain of calculations as well as brain of science. Here are some ways in which this can be done:-

How To Measure Density Of Floating Object

How to Measure Density of Floating Object

1. What Happens When an Object Is Put On Water Surface:-

When we put an object over water surface, a significant amount of water is displaced by it. Suppose if we take two beakers “A” and “B” with “A” being bigger than “B” and if we fill beaker “B” with water till its top placing it inside the beaker “A” and then we put an object in beaker “B”, the amount of water displaced by that object will get collected in beaker “A”. If we calculate the volume of this collected water and then make calculations, we can easily get the density of the object.

2. The Reason Behind:-

Any object is able to float over water only when its force of buoyancy or buoyant force is equal to its weight.  Density is mass per unit volume or we can write it in a numerical or mathematical form as mass/volume or mass divided by volume or we can write it as a numerical formula


where ρ= density, m=mass and V= volume.

3. Calculating the Density of Floating Object:-

We measure the mass of object by weighing it and Volume is the level of water that we got in Beaker “A”. If we divide the mass obtained by this volume, we will get the density of the object and that too very much accurate if we do not make mistakes in calculations.

4. Some More Facts to be mentioned:-

Being a researcher of volumes you may find some problems while solving derivations based on the same and thus I am mentioning a few facts related to the same. One such point to be considered is the calculation of upthrust which is equal to the weight of liquid displaced or the weight of the object.  Besides this, I would like to tell you that at some places, we can even consider the weight of the object but only if we are clear about the formulas of conversion of one unit into the other.

5. Perform It for Several Objects:-

You can face a difficulty while trying to perform this approach for the first time. We always assume the object’s density to be known in such cases as it can’t else be performed in a laboratory or at home. Just perform it for several other objects and you will be clear how mass and volume of an object make an impact on its density. Take a register and observe the density reports for few objects. Compare them and analyze the results. You will soon become an expert in finding the densities of floating objects.