Heating Matter Changes

Overview

This lesson investigates how heat changes solids, liquids, and gases. Students carry out repeatable, fair tests to measure temperature change and observe expansion/contraction, then use particle ideas to explain the observable results.

Learning intentions

• WALT investigate how heating affects the observable properties of solids, liquids and gases.
• WALT plan and conduct a repeatable fair test by deciding variables, measuring accurately and recording data.
• WALT use particle models to explain why heat causes expansion and contraction in different states of matter.

Success criteria

Students can:

• I can classify substances I observe as solid, liquid or gas using evidence.
• I can measure and record temperature change with reasonable precision.
• I can explain expansion/contraction using particle motion and spacing.
• I can identify possible sources of error and how they affect my results.

Curriculum links

• Students use particle modelling to explain observable properties of solids, liquids and gases.
• Students plan and conduct repeatable investigations with fair-test variables, safe procedures and risks considered.
• Students compare methods/findings, recognise possible sources of error, and use evidence to form conclusions.
• Students use equipment to observe, measure and record data with reasonable precision, using tables as appropriate.

Lesson structure ({total minutes})

1. 0–10 min · Hook and connect to prior learning. Teacher shows three quick teacher demos/images: heated metal strip, warm water in a jar, and a sealed balloon over a bottle with warm air (no need for close detail). Students do a quick sketch-and-label: “What changed?” and “Which state(s)?” in notebooks.

2. 10–20 min · Mini-lesson: observable change + particle explanation. Teacher models a simple particle diagram: in solids particles are closely packed and vibrate; in liquids particles stay close but slide; in gases particles are far apart and move freely. Students join the teacher in a “heat makes particles…” sentence frame: “Heat increases particle ___ and changes spacing, leading to ___.”

3. 20–45 min · Investigation 1 (stations): solids expansion measurement. Teacher sets up station trays and safety reminders (hot-water only, handling gloves/tongs, no tasting). Students work in pairs at one station: measure the change in length (or height) of a metal strip/changing loop size using a marked ruler/spacer before and after controlled heating time. Students record: starting temperature, final temperature (measured with thermometer), length change, and heating time.

4. 45–60 min · Investigation 2 (stations): liquids and gases observations with temperature. Teacher rotates groups to a second station. Option A (liquid): warm water in a measuring jug/jar—students measure temperature change and observe volume/level movement using markings. Option B (gas): warm air inflates a balloon—students compare balloon size using a pre-marked scale or length of string loop, and record temperature of the air source near the bottle (as a proxy) and time. Students record consistent data in the same table format.

5. 60–70 min · Share, compare and evidence conclusion. Teacher prompts: “Which state expanded more (or showed the clearest change)? What does your data suggest?” Students complete a short comparison using evidence sentences: “My evidence shows… because I measured…” and “A possible error is…”

6. 70–80 min · Exit ticket: particle model + fair test reflection. Students answer two prompts:

• “Use particles to explain why heating caused expansion/contraction.”
• “Name one variable you controlled and one possible source of error.”

Resources

• Thermometers (one per station or shared set) and heat-safe gloves or tongs
• Hot water in insulated containers (teacher handled), measuring jugs/cylinders
• Metal strips with ruler scale or marked measuring tools; spacers for consistent measurement
• Marked jars/bottles for volume/level observations
• Balloons, bottles, flexible tubing if needed; string/markers for size comparison scale
• Stopwatch/timer, data tables (printable), pencils, whiteboards/notebooks
• Safety signage, goggles, towel/heat mat
• Teacher timer for rotation and structured data collection

Assessment

• Teacher circulates during station work: checks temperature recording accuracy and table completeness.
• Formative questioning: “What variable did you keep the same? How do you know?”
• Exit ticket review: ability to connect observable changes to particle motion/spacing and to identify fair-test controls or errors.

Differentiation

• Support: provide partially completed data tables and sentence starters (“I controlled… I measured… I observed…” “Heat makes particles…”).
• Support for measurement: model how to read thermometer at eye level; offer a “check-in” midway through each station.
• EAL/SEN: allow verbal explanation into partner speech before writing; use word banks for solid/liquid/gas, expand/contract, particles, temperature.
• Extension (advanced learners): require a “best-fit” claim from data (e.g., “liquids expanded more than solids in our test because…”), plus a quantified estimate of uncertainty (e.g., “measurement error may be about ±1 mm”).
• Challenge consistency: ask some students to propose an improved method to reduce one identified error (e.g., longer/shorter heating time, more repeats, more precise scale).

Differentiation (Extension activities for advanced learners)

• Add one repeat trial: students collect one extra data set and compare results for consistency (range and mean).
• Advanced prompt: “Predict what would happen if we used double the heating time. Which state would show the greatest change, and why?” Students justify using particle spacing/motion.