The tiny dots represent particles whose motion is greatly slowed. Turning up the model temperature increases their average motion without changing their number or size. Cooling reverses that comparison. Temperature describes a group average: one slow particle can still be present in a warmer sample. Keep the material and container unchanged for a fair test.
Matter and chemistry · Discover & try
What changes when particles are heated?
Reading level 2 of 5 · DevelopingChange
Word help
temperature
A measure related to particles’ average kinetic energy.
heat
Energy transfer caused by a temperature difference.
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Idealised fixed-volume gas; motion is slowed and no actual heating experiment is required.
What to look for
- Count stays fixed
- A range of speeds remains
- Cooling reduces average motion
Explain what you noticed
A sealed sample is cooled without losing material. Which change fits this model?
Keep this idea: Compare average motion without inventing extra particles.
Follow the sources
- American Chemical Society — Molecules in Motion
- American Chemical Society — Heat, Temperature, and Conduction
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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