Density RP

• Calculating the density of a regularly shaped object

  1. Measure the dimensions of the regular shape and calculate the volume

  2. Measure the mass of the shape using a calibrated balance

  3. Calculate density from the mass and volume
• Volume of a prism


  Volume = area of face x height
• Volume of a rectangular prism

  Volume = Length x Width x Height
• Volume of a sphere

  Volume = 4/3 x 𝜋 x radius³
• Equation to calculate density

  Density = Mass / Volume
• Measuring the object's mass


  Use a digital balance, which should be zeroed before placing the object on it to avoid a zero error
• Converting from g/cm³ to kg/m³

  Multiply the value by 1000
• Calculating the density of an irregularly shaped object

  1. Measure the mass of the irregular shape

  2. Fill a displacement can with water and submerge the object

  3. Record the volume of water that has been displaced

  4. Calculate the density from the mass and volume
• Collecting the displaced water


  Place a measuring beaker under the can spout
• Filling the displacement can

  Fill the can until water starts to drip out of the spout and into the beaker, then wait until the dripping just stops before submerging the object
• Calculating the density of a liquid

  1. Measure the mass of the empty measuring cylinder

  2. Pour around 100cm³ of liquid into the cylinder and record the volume

  3. Measure the mass of the cylinder with liquid in, and subtract the cylinder's mass to calculate the mass of liquid

  4. Calculate density from mass and volume
• In general, solids are more dense than liquids since their particles are more tightly packed together meaning there is more mass per unit volume
• Density


  The mass per unit volume of a substance or object
• The unit of density is kilograms per meter cubed
• Regular objects


  • Have dimensions that are easy to measure
• Determining density of regular objects

  1. Measure mass using a balance

  2. Measure dimensions using a ruler

  3. Calculate volume from dimensions

  4. Apply density equation
• Irregular objects


  Have dimensions that are not easy to measure
• Determining density of irregular objects

  1. Measure mass using a balance

  2. Use displacement method to measure volume

  3. Apply density equation
• The volume of water displaced is equal to the volume of the object