Introduction to Matter

Overview

In this first lesson of the unit, students explore what “matter” is and investigate how substances can be classified as solids, liquids and gases. They discuss observable properties and use simple particle models (role-play and diagrams) to explain why properties differ.

Learning intentions

Students will:

• explain that matter is anything that has mass and takes up space
• classify everyday materials as solids, liquids or gases based on observable properties
• model particle arrangement and motion in solids, liquids and gases to explain observable differences
• use guided discussion to describe what they think is between particles

Success criteria

Students can:

• sort examples into solids, liquids or gases and justify their choices using observable properties
• describe key particle ideas: particles are arranged differently and move differently in solids, liquids and gases
• use a labelled model (drawing or role-play) to explain why a substance behaves the way it does
• contribute to discussion respectfully and ask a question about matter

Curriculum links

• AC9S5U04: explain observable properties of solids, liquids and gases by modelling the motion and arrangement of particles
• AC9S5I01: pose investigable questions to identify patterns and make reasoned predictions (during class discussion)
• AC9S5I04: construct and use appropriate representations, including visual/physical models (particle role-play and diagrams)

Lesson structure (80 minutes)

1. 0–10 min · Hook and definitions. Teacher shows 3 items (ice cube in a cup, water in a clear container, and air in a balloon) and asks: “Which of these is matter, and why?” Students think-pair-share, then record one sentence: “Matter is…”

2. 10–25 min · Quick classification challenge. Teacher displays a collection tray (e.g., sand/gravel, cooking oil, a sealed plastic bag with air, marbles, vinegar in a bottle, shaving cream). Students work in pairs to sort into solids, liquids and gases using only observable features (shape, volume, spreading, filling a container). Pairs hold up labels and explain their reasoning.

3. 25–35 min · Teach: observable properties link to particles. Teacher leads a short guided explanation: solids keep shape, liquids change shape but keep a similar volume, gases expand to fill the container. Students use sentence starters to connect observation to particle ideas: “Because particles in a solid are… the solid…”.

4. 35–55 min · Particle role-play modelling. Teacher assigns roles within groups of 4–5 students: “particles” using wristbands or paper circles. Students act three rounds:

• Solid: particles in a tight cluster with minimal movement
• Liquid: particles close together but sliding past each other
• Gas: particles spaced far apart and moving freely, filling available space After each round, students complete a 3-box quick sheet: draw or write “particles are… / they move… / the substance does…”

5. 55–65 min · Guided discussion: “What is between particles?” Teacher facilitates discussion using prompts: “What do you think is between particles?” “Is it still part of the substance?” Students share ideas with a whole-class chart: model-consistent ideas (space between particles; particles have gaps that differ by state).

6. 65–75 min · Evidence check: mini-comparisons. Teacher sets up a short station rotation (2–3 minutes each, whole class stays seated if needed):

• Cup A: water poured into a wider cup
• Cup B: sand/gravel placed in a tray
• Cup C: balloon gently compressed in a safe demonstration area (teacher-led) Students answer 2 prompts: “What observable change happened?” and “Which particle model matches?”

7. 75–80 min · Exit ticket. Students complete one paragraph or short responses:

• “One property that helps us identify a solid is…”
• “A particle model for a gas is… (arrangement and motion)”
• “One question I have is…”

Resources

• Collection of classroom materials: sand/gravel, marbles, cooking oil, water in clear containers, sealed plastic bag with air, balloon with air
• Labels/signs: solid, liquid, gas
• Wristbands or paper circles for “particle” role-play; group recording sheet (3 states)
• Station cups/trays: water containers, wider cup, small tray for sand/gravel
• Exit ticket slips and pencils/whiteboards
• Safety reminder cards (no tasting; careful handling of spills)

Assessment

• During sorting: teacher checks that justifications use observable properties (not guesses)
• During role-play and quick-sheet: check for correct particle arrangement/movement language linked to state behaviour
• Exit ticket: identifies misconceptions (e.g., “gases have fixed shape” or “particles are touching in gases”)

Differentiation

• Support:
• Provide sentence starters and word bank: “shape”, “volume”, “spreading”, “fills the container”, “particles are close/far”, “move slowly/quickly”
• Offer a partially completed 3-box model sheet with prompts and icons
• Use mixed-ability groups with clear roles (timekeeper, modeller, recorder, reporter)
• For EAL/learning support:
• Use visuals (state diagrams) and consistent language across the lesson
• Allow oral responses first, then brief written recording
• Challenge/extension for advanced learners (without adding a separate activity block):
• Ask “prediction” questions: “If we warm a solid, which particle model might it start to change into?” and “What evidence would you look for?”
• Request an extra comparison sentence: “Liquids are different from solids because…”.