LuduminaPM-05 · PM-U3 · Planned
Gas motion, temperature and pressure
Learning objectives
Explain pressure from random particle collisions; predict pressure rise when fixed-volume gas warms.
8463 §§4.3.3.1 / 8464 §§6.3.3.1
DfE single-science pp.42–43 / Combined pp.35. Evidence checked 30 September–1 October 2026. Skills: WS1.2,3.5,3.6; MS4a.
Needs firstPM-03
Explanation
Gas particles move randomly and exert forces through collisions with walls. At fixed volume, heating increases average kinetic energy, increasing pressure through more frequent and stronger collisions. A pressure–temperature proportionality must not use Celsius as though zero Celsius meant zero particle motion.
Concepts, equations and units: Gas pressure Pa; temperature °C used qualitatively; average kinetic energy rises with temperature; fixed mass/volume conditions.
Prediction, demonstration and game exercise
Predict, observe, explain
Warm a sealed fixed-volume model gas; count wall collision impulses with animation slowed and labelled.
Planned learner game exercise
Choose warmer/cooler settings and compare pressure readings; explain constraints of particle representation.
Independent practice
Interpret pressure–temperature data qualitatively and write a collision-based explanation.
Original practice example · Shared
A sealed rigid gas container warms. Explain the pressure change without changing particle size.
Show working and model answer
Working / reasoning
Average kinetic energy/speed increases; collisions with the wall are more frequent and forceful, increasing force per unit area.
Answer
Pressure rises at fixed mass and volume because wall-collision forces increase.
Exit check and success criteria
Explain higher average speed/more forceful and frequent wall collisions at fixed volume; avoid unsupported proportionality in °C.
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
Gas pressure is caused by particles pressing without motion; pressure rises because particles expand; p∝temperature in °C.
Practical preparation
Optional teacher-led pressure/temperature demonstration; no RP.
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.