LuduminaPM-02 · PM-U1 · Planned
Measuring density: solids and liquids
Learning objectives
Select methods for regular solids, irregular solids and liquids; evaluate volume/mass errors.
8463 §§4.3.1.1;8.2.5 / 8464 §§6.3.1.1;10.2.17
DfE single-science pp.42–43 / Combined pp.35. Evidence checked 30 September–1 October 2026. Skills: WS2.3–2.7,3.4,3.7; MS2a,2b,3c,5c.
Needs firstPM-01
Explanation
Regular solids can use dimensions; irregular solids can use displaced volume if the method is suitable. A liquid needs its mass without the container and a measured volume. Tare, meniscus and trapped-air errors affect the result.
Concepts, equations and units: ρ=m/V; cube/cuboid volume from lengths; displacement volume; tare/subtraction for liquid mass; kg/m³ or g/cm³ converted explicitly.
Prediction, demonstration and game exercise
Predict, observe, explain
Use balance, ruler and displacement vessel; show meniscus/parallax and trapped air errors.
Planned learner game exercise
Measure all three sample types virtually; reject unsuitable methods and collect repeats.
Independent practice
Three density estimates, uncertainty comparisons and a method improvement.
Original practice example · Shared
A container weighs 50 g empty and 130 g with 100 cm³ of liquid. Find liquid density.
Show working and model answer
Working / reasoning
Liquid mass = 130 − 50 = 80 g; ρ = 80/100 = 0.80 g/cm³.
Answer
0.80 g/cm³, equivalent to 800 kg/m³.
Exit check and success criteria
Correct methods for every sample type plus two valid densities and one quantified uncertainty estimate.
During practice, compare the prediction with evidence and give an error-specific prompt. The exit item uses a fresh context or fresh values, answered independently.
Misconceptions, practical links and mastery
Check these misconceptions
Liquid density uses container mass; displacement volume is total water volume; repeat readings correct a mis-zeroed balance.
Practical preparation
RP-P5/RP-C17; regular/irregular solids and liquids; AT1.
Virtual preparation and revision only. Required hands-on activities and school records remain separate.
Proposed mastery
0: not yet evidenced. 1: supported. 2: independent exit criteria met. 3: successful changed-context transfer. Advance at 2; revisit with fresh retrieval. These are not GCSE grades.