Volume of an Irregular Object


Everything is made of matter, and matter has both chemical and physical properties. physical properties of matter are observable and include mass, volume, and density. Mass is the amount of matter in an object and can be found by using an electronic balance or scale. Volume is the amount of space an object occupies and can be determined by measuring the amount of water that a submerged object displaces. The formula for determining density is:

Density = Mass of the object / Volume of the object


Determining the volume of an irregularly shaped object can help determine its density.


The materials used in this lab included a rubber stopper, small rock, shell, 100 ml graduated cylinder, electronic balance, water, paper, and pencil.


Obtain three, irregularly shaped objects --- a rubber stopper, a shell, and a rock. Estimate the volume and mass of each object and record this in the data table. Use an electronic balance to mass each object and record the masses in the data table. Fill a graduated cylinder approximately half way with water and record this initial volume. Place one of the objects into the graduated cylinder and record the final volume. Subtract the initial volume of the water from the final volume of water to find the volume of the water the object displaced. Record this as the object's volume in the data table. Remove the first object and repeat this process of determining volume for the other two objects. Determine each object's density by dividing their mass by their volume. Record each density in the data table.


Data Table
Object estimated mass (g) estimated volume (ml) actual mass (g) initial volume of water (ml) final volume of water (ml) volume of object (ml) density (g/ml)
Rubber stopper 19.3 10 9.3 50 56 6 1.55
Shell 6.0 2 3.3 50 51.5 1.5 2.2
Rock 10.0 5 9.3 50 55 5 1.86

Discussion and Conclusion

Objects that are irregular in shape can have their volume determined by measuring the amount of water that they displaced when submerged in a known amount of water. The increase in volume from the initial water level to the final water level is the volume of the object. Once the volume is determined and the actual mass measured then the object's density can also be determined. The formula for finding density is the mass of the object divided by the volume of the object. For example, since the rock had a mass of 9.3 grams and a volume of 5 ml, the density of the rock was determined to be 1.86 grams/ millimeters.