Density
Science, Physics. Usually met in years 8 to 11.
Use density = mass ÷ volume to find density, mass or volume, in several units.
What you practise
- Finding density
- Finding mass or volume
- Cubes and units in kg/m³
Ends with cubes, where the volume must be worked out first. Practice moves up a level when a round goes well and down when it does not.
Sample questions
Each sample comes with the method and the reason every wrong option is wrong. Real practice rounds are ten questions at your level.
Sample question, level 2 of 5
A metal has a density of 5 g/cm³. What is the mass of 3 cm³ of it?
- 1.667 g
- 0.6 g
- 15 g
- 8 g
- 150 g
Show the answer and method
Answer: C, 15 g
The method: Mass = density × volume = 5 × 3 = 15 g.
Why the other options are wrong:
- A, 1.667 g: Density was divided by volume. Mass = density × volume.
- B, 0.6 g: The division is upside down. Mass = density × volume.
- D, 8 g: The density and volume were added.
- E, 150 g: The decimal point is one place out.
Sample question, level 4 of 5
An object has a mass of 500 kg and a volume of 0.5 m³. What is its density?
- 0.001 kg/m³
- 250 kg/m³
- 499.5 kg/m³
- 1,000 kg/m³
- 1 kg/m³
Show the answer and method
Answer: D, 1,000 kg/m³
The method: Density = mass ÷ volume = 500 ÷ 0.5 = 1,000 kg/m³.
Why the other options are wrong:
- A, 0.001 kg/m³: The division is upside down. Density = mass ÷ volume.
- B, 250 kg/m³: The mass was multiplied by the volume. Density is mass divided by volume.
- C, 499.5 kg/m³: The volume was subtracted from the mass.
- E, 1 kg/m³: The mass was divided by 1000 as if it were in grams. It is already in kg.
See where this fits: GCSE science with AQA and Key Stage 3.
Related topics: Forces, Electricity, Energy, Waves.
