Density and mass,weight

• Mass


  The amount of matter in a body
• Weight


  The gravitational force acting on an object
• SI unit for mass

  • kg
• SI unit for weight

  • N
• Earth's gravitational field is strongest at the Earth's surface and gets weaker as you get further away
• Gravitational field


  A region where a mass experiences a gravitational pull
• Gravitational field strength


  Gravitational force per unit mass
• SI unit for gravitational field strength


  • N/kg
• Mass


  Amount of matter in a body
• Weight


  Gravitational force acting on an object
• To measure mass, you need to use a spring balance
• Tape measure


  • Can measure several metres, flexible and measure a range of metres
• Metre ruler


  • Can measure centimetres up to 1m
• Vernier/digital callipers


  • Can measure the thickness of an object up to 15cm
• Vernier callipers


  • Outside jaws measure external diameter, inside jaws measure internal diameter, tail measures depth
• Volume


  The amount of space an object occupies
• SI unit for volume

  • m³
• Density


  Mass per unit volume
• SI unit for density

  • kg/m³, g/cm³
• Mass


  Also known as weight
• Gravitational field strength


  Defined as gravitational force per unit mass, in N/kg
• Mass is the amount of matter in a body
• Weight is the gravitational force acting on an object
• Earth's gravitational field


  Strongest at the surface, gets weaker as the object gets further away
• Volume


  The amount of space an object occupies, SI unit is m3
• Density


  The amount of mass per unit volume, SI unit is kg/m3
• To measure mass


  Use a spring balance
• Measurement tools


  • Tape measure (measure range of metres)
  • Metre ruler (measure up to 1m)
  • Vernier/Digital caliper (measure thickness of objects)
• Vernier caliper has:

  • Inside jaw to measure internal diameter
  • Outside jaw to measure external diameter
  • Tail to measure depth of a container
• Earth's gravitational field is strongest at earth's surface but gets weaker as the object gets further away
• Gravitational field


  A region which experiences a gravitational pull
• Gravitational field strength


  Defined as gravitational force per unit mass
• Weight


  Gravitational field strength x Mass
• Vernier caliper


  • Inside jaw: Measure internal diameter of an object
  • Outside jaw: Measure external diameter of an object
  • Tail: Measure depth of a container
• Volume


  Anything that occupies space
• Density = Mass / Volume
• The formula to calculate density is density = mass / volume
• Density is the amount of matter per unit volume.
• Mass is measured in kilograms (kg)