Grade 6 · Science · 30 minutes
Unit 2 · Matter and Earth’s Water · Lesson 1 of 2
Draw What Warming Changes
Connect a short scientific description to particle diagrams of a pure substance.
Mr. S Teaches · Original starter mini-lesson · MS6-SCI-03Learning objective
Use three particle diagrams to explain changes in movement and arrangement as a pure substance warms.
Before you begin
- Distinguish solid, liquid and gas.
Gather your materials
- Paper or notebook
- Pencil and the passage, model directions or data printed in this lesson
Language to know
- particle
- A tiny unit used in a model of matter.
- temperature
- A measure related to particles’ average motion energy.
- state change
- A change among solid, liquid and gas without making a different substance.
Understand the concept
Model text: In a solid, particles stay close and vibrate around positions. In a liquid, they remain close but move past one another. In a gas, particles are much farther apart and move freely between collisions. Adding thermal energy can increase motion and can cause a state change. The particles themselves do not grow larger when the substance expands. Use equal-sized dots in each diagram. This qualitative model describes a pure substance rather than a chemical reaction.
Teach it step by step
- Read the model text and mark the phrase describing spacing in each state.
- Draw nine equal dots for a solid, nine for a liquid and nine for a gas. Keep the number and size of dots unchanged.
- Add short movement arrows and describe the different arrangements using the text.
- Predict what removing thermal energy might do, and revise a diagram that incorrectly uses larger dots to show heating.
Make the thinking visible
Worked example or model response
Nine dots in a regular close pattern with tiny vibration marks can represent a solid. Nine close but irregular dots with movement arrows can represent a liquid. A gas drawing spreads the same nine dots farther apart. The drawing changes arrangement, not identity or dot size.
Guided practice
Together annotate a solid-to-liquid arrow with “thermal energy added; particles rearrange and move past one another.” Explain which words in the text support the drawing.
Independent practice
Create a gas-to-liquid model and a three-sentence explanation. Identify the error in “Heating makes every particle swell to twice its size.”
Quick assessment
Why must the dot count stay the same across these state-change models?
Answer key & assessment criteria
Answers and teaching guidance
- Guided: The text says solid particles vibrate around positions while liquid particles move past one another; added thermal energy can change state.
- Independent: Gas-to-liquid drawings should bring equal-sized dots closer as energy is removed. Heating changes motion and spacing in this model, not the size of individual particles.
- Quick check: A state change of the same closed sample conserves the represented matter; no particles are created or destroyed.
Look for: Look for a claim that answers this lesson’s question, accurate use of the supplied evidence and an explanation of a limit or alternative. Ask the learner to point to the detail supporting each inference.
Make it work for your learner
More support
Use movable paper dots with different-colored movement arrows; supply the three-state comparison table.
Extension challenge
Explain why a larger container of a substance can contain more total thermal energy than a smaller sample at the same temperature.
Selected contributions · Official sources
Standards connections
Selected NGSS band contribution; not complete performance expectation coverage.
Contributes to NGSS performance expectation
MS-PS1-4NGSS · Grades 6–8 band
Model particles as thermal energy and physical states change.
Read the official performance expectation ↗The lesson models selected qualitative changes in a pure substance. It does not examine pressure effects or detailed energy behavior at every phase transition.
Source and mapping checked 2026-11-04. This mini-lesson contributes selected skills; it does not claim full attainment.
Supporting Common Core literacy connection
RST.6-8.7Common Core · Grades 6–8
Connect scientific prose with a diagram, model or table.
Read the official standard ↗The provided scientific passage/model is explicitly analyzed in the activity. This selected literacy practice does not establish subject-content alignment or complete coverage of the standard.
Source and mapping checked 2026-11-04. This mini-lesson contributes selected skills; it does not claim full attainment.