Density | Physics for GCSE/IGCSE - Year 11 PDF Download

Density

• Density is defined as: The mass per unit volume of a material
• Objects crafted from materials with low density usually exhibit low mass, whereas those fashioned from high-density materials tend to possess high mass.
  • For instance, a bag filled with feathers is considerably lighter compared to a similar-sized bag filled with metal.
  • Alternatively, a balloon, despite occupying a larger volume, is less dense than a small bar of lead.
• Density is determined by the relationship between mass and volume, expressed by the following equation:
  
• Gases, for instance, have lower density compared to solids because their molecules are more dispersed, resulting in the same mass being spread over a larger volume.
  
• This equation can be reorganized using a formula triangle:
  
• The units of density are determined by the units used for mass and volume. For example, if mass is in grams and volume in cubic centimeters, then density is expressed in grams per cubic centimeter (g/cm³).
• Materials denser than water (1000 kg/m³) will sink when placed in water, as shown in the common materials density table:
  
• The volume of an object may not always be given directly; it can be calculated using the appropriate equation based on the object's shape.