States of matter

Overview

Students connect the three common states of matter to what students observe about fluids. They investigate how temperature affects state changes and how that relates to fluidity.

Learning intentions

• Students will be able to describe the three states of matter (solid, liquid, gas).
• Students will be able to explain how fluids fit into these categories.
• Students will investigate and describe how temperature changes can cause melting, freezing, evaporation, and condensation.
• Students will use observations and evidence to support a claim about state changes.

Success criteria

• I can describe solids, liquids, and gases using key properties (shape and volume).
• I can explain why liquids and gases are considered fluids (how they flow).
• I can identify state changes caused by heating or cooling and describe what happens to particles.
• I can use evidence from a quick investigation to support my claim.

Curriculum links

• Matter and its observable properties (solids, liquids, gases; properties like shape and volume).
• Changes of state caused by heating and cooling.
• Fluidity and the idea that some matter flows more easily than others.
• Science and engineering practices: observe, measure, record data, and communicate findings.

Lesson structure ({total minutes})

1. 0–5 min | Launch and connect Show three everyday items (ice cube, room-temperature water, balloon or gas-filled container) and ask: “Which could flow? Which keeps its shape? Why?” Students do a quick think–pair–share and record one prediction.

2. 5–12 min | Mini-lesson: states + fluids Teach a short model using a class chart: solids (fixed shape and volume), liquids (fixed volume, changing shape), gases (neither fixed shape nor fixed volume). Emphasize fluids as substances that flow—liquids and gases—and connect to everyday examples (pouring water, air moving).

3. 12–20 min | Temperature and state change demo Demonstrate or show images of melting and evaporation (e.g., warm water vs. ice; kettle/evaporation video if available). Prompt students to describe what they observe (appearance, temperature change where relevant) and translate it into “state change” language (melting/freezing, evaporation/condensation).

4. 20–30 min | Investigation stations (data collection) In groups of 4–5, students rotate through 2–3 stations:

• Station A: “Melting evidence” (e.g., observe ice melting in a labelled container over time; record qualitative changes and time).
• Station B: “Evaporation evidence” (compare two small samples of water exposed to different conditions, such as air flow vs. still air; record mass change if scales are available, or otherwise record time/appearance).
• Station C: “Condensation evidence” (warm vs. cool surface/condensation on a cold surface; record observations). Students complete a simple table: temperature condition, observation, state change label, and claim starter (“This suggests…”).

5. 30–37 min | Evidence-to-claim writing Students choose one station result and write a CER paragraph (claim, evidence from observations, reasoning using states/temperature). Provide sentence starters: “I claim that… because… This happens when…”.

6. 37–43 min | Share-out and class consensus Groups share one CER. As a class, create a “temperature → state change → fluid/flow link” summary. Correct misconceptions (e.g., “gases are not ‘empty’—they occupy space and can flow”).

7. 43–45 min | Exit ticket Students answer:

• “Name the three states of matter and one property of each.”
• “Choose one state change and explain how temperature causes it.” Collect to inform next lesson.

Resources

• Ice, water, and containers (labelled with student-friendly names)
• Small cups/beakers, paper towels, trays to manage spills
• Thermometers or temperature probes if available
• Timer and student recording sheets
• Condensation materials (e.g., cold can/bottle with warm air exposure)
• Optional: access to scales for evaporation station
• Station instructions with visuals and key sentence starters
• Balloon or visible gas container for properties discussion
• Whiteboard/chart paper for class summary
• Safety gear: goggles (recommended for demonstrations), clear cleanup plan

Assessment

• Formative: teacher checks station notes and CER drafts during circulation.
• Formative: exit ticket responses to confirm understanding of states, fluids, and temperature-driven state changes.
• Summative-in-mini: accuracy of state change labels and the link between temperature change and observations.

Differentiation

• Support (ESL/ELL): provide word banks with “solid, liquid, gas, melting, freezing, evaporation, condensation, flow”; allow oral responses and partner recording; use sentence starters for CER.
• Support (SEN): reduce station record load (e.g., “tick the property” + one sentence); provide visuals for each state and change; offer a simplified graphic organizer.
• Extension: challenge students to predict outcomes under a new condition (e.g., “What happens if we increase heat faster?”) and justify using particle/model reasoning; include a second CER comparing two stations.
• Language flexibility: accept answers using everyday language paired with required science terms (e.g., “melting—ice turning to liquid”).