Density (DP IB Physics)

Density

• Density is the mass per unit volume of an object

  • If two objects occupy the same volume, the object with a lower density will have a lower mass

  • For example, a bucket filled with feathers will have a lower mass than the same bucket filled with sand, because feathers have a lower density than sand

• The units of density depend on the units used for mass and volume:

  • If the mass is measured in g and volume in cm³, then the density will be in g / cm³

  • If the mass is measured in kg and volume in m³, then the density will be in kg / m³

How to calculate density

Gases are less dense than liquids due to their molecular arrangements

• The volume of an object may not always be given directly but can be calculated using the appropriate formula

Volumes of common 3D shapes