Units & DIMENSIONS - DENSITY & RELATIVE DENSITY
Definition of Density:
Density is a word we use to describe how much space an object or substance takes up (its volume) in relation to the amount of matter in that object or substance (its mass). Another way to put it is that density is the amount of mass per unit of volume. If an object is heavy and compact, it has a high density. If an object is light and takes up a lot of space, it has a low density.
So, if we know the volume and mass of an object, we can calculate the density using the equation
density = mass / volume.
\(\rho = \frac{{mass}}{{volume}} = \frac{m}{v}\)
Units of Density:
The SI unit of density is kilogram per cubic meter (kg/m3). It is also frequently represented in the CGS unit of grams per cubic centimetre (g/cm3).
Density allows you to solve for mass and volume if given the other quantity. Since the density of common substances is known, this calculation is fairly straightforward, in the form.
One of the most common uses of density is in how different materials interact when mixed together. Wood floats in water because it has a lower density, while an anchor sinks because the metal has a higher density. Helium balloons float because the density of the helium is lower than the density of air.
How to Find Density?
Recall that though density is simply mass divided by volume, it is measured in units of grams per cubic centimetre because grams represent a standard weight, while cubic centimetres represent the volume of the object.