Water and Heat

Overview

In this lesson, students explore how heat can change materials, with a focus on water and everyday evidence of heating and cooling. They observe, discuss, and record changes using simple science language.

Learning intentions

Students will be able to:

• identify how heating and cooling affect water
• make careful observations of a fair test involving water temperature or change
• use everyday language to describe change, such as warm, hot, cool, and freeze
• record observations in a simple table or science journal with drawings and words

Success criteria

I can…

• describe what happens to water when it is warmed or cooled
• explain that heating and cooling are ways to transfer heat
• complete a simple recording table using observations from my test
• share my results with a reason based on evidence

Curriculum links

• Science understanding: observable properties and changes in materials, including water when heated or cooled
• Science inquiry: ask questions, make predictions, observe and measure informally, and record findings
• Science literacy: use simple scientific vocabulary to communicate observations and results

Lesson structure (60 minutes)

1. 5 minutes – Hook and question Teacher shows a container of cold water and a container of warm water (handled safely). Students do a quick think–pair–share: “What do you notice?” and “How might the water have changed?”

2. 8 minutes – Build shared vocabulary Class creates a word bank on the board: warm, hot, cool, freeze, melt, change, observe, record, evidence, and temperature (if available). Teacher emphasises that we can use senses to notice, but we should also use a measure when possible (thermometer).

3. 10 minutes – Model inquiry steps Teacher demonstrates the investigation setup with one group:

• Question: “How does warming and cooling water change it?”
• Prediction: “I think the water will become …”
• Method: compare water in two cups by measuring temperature and/or observing changes over time
• Safety reminder: no tasting; careful with hot water; use adult handling for any very warm water Students practise the sentence stem: “We observed… therefore…”

4. 20 minutes – Small-group investigation (fair test) In groups of 4–5, students run the comparison:

• Cup A: water stays at room temperature or is gently warmed by teacher-provided warm water
• Cup B: water is cooled (e.g., placed in a tray with ice or cooler) Students measure temperature at the start and again after a set time (e.g., 10 minutes). If temperature measurement isn’t available for all, students still record observations such as “becomes warmer/cooler” and any visible change. Teacher circulates using prompts: “What evidence do you have?” “What changed?” “What stayed the same?”

5. 10 minutes – Recording and reasoning Students complete a simple table in their science journal:

• “At the start: Cup A … / Cup B …”
• “After 10 minutes: Cup A … / Cup B …”
• Drawing of each cup
• One sentence explaining the change they observed Teacher checks for clarity: students must include both observation and evidence.

6. 5 minutes – Share-out Each group shares one key finding. Teacher records common statements (e.g., “Warm water feels hotter and its temperature is higher”) and links to heat transfer: “Heat moves from warmer things to cooler things.”

7. 2 minutes – Exit ticket Students answer: “One change I observed was…” and “I used evidence by recording…” Teacher collects quickly for formative assessment.

Resources

• two sets of cups or small containers per group (labelled A and B)
• thermometers or temperature stickers (one per group if possible; share if needed)
• trays and ice (or cold packs) for cooling
• teacher-provided warm water (safe temperature only) and a way to handle safely
• science journals or recording sheets with a simple observation table
• markers or pencils and crayons for drawings
• paper towels, a mat, and a bucket for spills
• sentence stem strips (“We observed…”, “This shows…”, “Therefore…”)
• safety equipment: goggles if available, gloves if teacher uses warm water

Assessment

• Formative observation during investigation: students record accurately and use appropriate science language
• Science journal check: evidence of observations and a completed comparison table (with start and end)
• Exit ticket: can students describe a change and link it to evidence

Differentiation

• Support: provide a partially filled recording table and sentence starters; pair students strategically; allow drawings only if writing is limited
• Support for EAL: use visual word bank and sentence frames; allow oral responses before writing
• Extension: ask “Why do you think the temperature changed at different rates?” and prompt students to compare results across groups
• SEN: offer additional time, reduce writing load to one key sentence, and provide a teacher-led checklist for observations