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 Displacement measured in a graduated cylinder

If a container is filled with water and a rock is dropped into it, some water will overflow.  Water is said to have been displaced by the rock.   The volume or the amount of space taken up or the number of cubic centimeters that are displaced, is equal to the volume of the rock.  When any object is dropped into a container partly filled with water, the level of the water surface is raised.  A completely submerged object always displaces a volume of liquid equal to its own volume.  This is a good method for determining the volume of irregularly shaped objects.

Volume and mass is important in determining the density of an object, which is difficult to measure directly. Mass or the quantity of matter in a body is easily measured by using an analytical balance (i.e., triple beam balance) or an electronic scale that measures mass.  Then once you find the volume and then the mass you can mathematically determine the density by using the following relationship:

D (density)  =  M (mass) / V (volume)

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