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Class 8 Science — Density, and how to measure it

Calculate density from mass and volume, find the volume of an irregular solid by displacement, and say what heating does to density.

Name: ________________________

  1. 1.Match each quantity to the instrument or unit the chapter gives for it.

    • The quantity of matter in an object
    • The space an object occupies
    • The SI unit of volume
    • A submultiple of a litre, equal to one cubic centimetre
    • the millilitre
    • measured with a weighing balance
    • measured with a measuring cylinder
    • the cubic metre

  2. 2.A stone sculpture has a mass of 225 g and a volume of 90 cm³. What is its density, in grams per cubic centimetre? Answer with a number.

  3. 3.Put the steps for finding the volume of an oddly shaped stone back into order.

    • Record the final volume once the level has risen
    • Tie the object with a thread and lower it slowly into the cylinder
    • Subtract the initial volume from the final volume
    • Fill a measuring cylinder with water and record the initial volume

  4. 4.Water is at its densest at 4 °C. As it cools further and turns to ice at 0 °C, what happens?

    • a) The mass decreases, which is what makes ice float
    • b) The particles pack closer together, so ice is denser and would sink but for the surface tension
    • c) The particles arrange themselves so as to take up more space, so ice is less dense and floats
    • d) The density stays exactly the same, since freezing is a physical change

  5. 5.Water in a measuring cylinder stands at 40 mL. A metal key is lowered in and the level rises to 47 mL. What is the key's volume, in cubic centimetres? Answer with a number.

  6. 6.Object B has a mass of 240 g and a volume of 60 cm³. What is its density, in grams per cubic centimetre? Answer with a number.

  7. 7.A closed box is 12 cm long, 5 cm wide and 4 cm high. What is its volume, in cubic centimetres? Answer with a number.

  8. 8.Object A has a mass of 200 g and a volume of 40 cm³. What is its density, in grams per cubic centimetre? Answer with a number.

Answer key — Class 8 Science — Density, and how to measure it

  1. 1. The quantity of matter in an object → measured with a weighing balance; The space an object occupies → measured with a measuring cylinder; The SI unit of volume → the cubic metre; A submultiple of a litre, equal to one cubic centimetre → the millilitre
  2. 2. 2.5
  3. 3. 1. Fill a measuring cylinder with water and record the initial volume 2. Tie the object with a thread and lower it slowly into the cylinder 3. Record the final volume once the level has risen 4. Subtract the initial volume from the final volume
  4. 4. c) The particles arrange themselves so as to take up more space, so ice is less dense and floats
  5. 5. 7
  6. 6. 4
  7. 7. 240
  8. 8. 5