Required practical · AQA, EDEXCEL, OCR
Required practical: Determine the density of a regular or irregular solid
Aim
To calculate density ρ = m/V using a balance and displacement method for irregular objects or ruler/caliper for regular blocks.
Method (step-by-step)
- Mass with a balance.
- Volume: ruler for cuboid; displacement can / eureka can for irregular solid.
- Repeat and mean; calculate ρ in kg m⁻³ or g cm⁻³ consistently.
Equipment
- Balance
- displacement can
- beaker
- ruler
Variables
- Independent: Material / object under test.
- Dependent: Calculated density.
- Control: Same balance calibration; same water volume procedure
Results & analysis
Compare to accepted values; discuss why air bubbles or wet masses shift results.
Graphs & interpretation
Not usually graphed — table and calculation focus.
Common mistakes (high yield)
- Using cm³ but reporting kg m⁻³ without conversion.
- Not submerging fully (trapped air).
Exam-style question prompts
- Why use displacement for a stone?
Exam tips
- 1 g cm⁻³ = 1000 kg m⁻³
Related topic revision
FAQs
Exam boards differ in wording; always follow your specification and your teacher’s practical notes. Back to GCSE Physics required practicals hub.