Required Practical 5:Density

• What should you be able to describe by the end of the video?

  How to determine densities of solids
• Why is it important to learn the details of density determination?

  It could come up as an exam question
• What does the density of a material tell us?

  The mass for a given volume
• How is density calculated?

  Density equals mass divided by volume
• What is the unit of density?

  Kilograms per cubic meter
• Is the density equation provided in the exam?

  No, it is not provided
• How are objects categorized for density determination?

  Into regular and irregular objects
• What is an example of a regular object?

  A cube
• How do you measure the dimensions of a regular object?

  Using a ruler
• What is the mass of the cube in the example?

  0.5 kg
• What is the length of each side of the cube?

  120 mm
• How do you calculate the volume of a cube?

  Length of the side cubed
• What is the volume of the cube calculated in the example?

  $0.001728 \text{ m}^3$
• What is the density of the cube calculated in the example?

  $2893.5 \text{ kg/m}^3$
• What is the method used to determine the volume of irregular objects?

  Displacement method
• What is the first step in determining the density of an irregular object?

  Find the mass using a balance
• What is a Eureka can used for?

  To measure displaced water volume
• What happens when the irregular object is placed in water?

  Water is displaced
• How do you measure the volume of water displaced?

  Using a measuring cylinder
• What does the volume of displaced water equal?

  The volume of the object
• What can you calculate once you have the mass and volume of an object?

  The density of the object
• What are the steps to determine the density of a regular object?

  1. Measure the mass using a balance.
  2. Measure the length of the side with a ruler.
  3. Calculate the volume by cubing the length.
  4. Use the density formula: density = mass/volume.
• What are the steps to determine the density of an irregular object?

  1. Measure the mass using a balance.
  2. Fill a Eureka can with water.
  3. Place the object in the water to displace it.
  4. Measure the volume of displaced water.
  5. Use the density formula: density = mass/volume.