Heat Changes States

Overview

In this lesson (lesson 8 of 12), students investigate how heat and cooling affect materials by linking energy to changes in states of matter. They will also collect categorical information using drawings and then compare patterns in the class data.

Learning intentions

• Students will collect categorical data about an everyday investigation using drawings.
• Students will use a class display to represent and interpret categories.
• Students will begin to describe, with support, how heating and cooling can cause changes to materials.

Success criteria

• I can draw one picture that matches a category and place it into the correct class category.
• I can help the class explain what the display shows (most and fewest).
• I can use simple science words (heat, cool, melt, freeze) to describe observations from the investigation.

Curriculum links

• Science and Technology focus on predicting and describing observable changes when heat is applied or removed.
• Conducting and representing data: sorting information into categories and interpreting simple displays.
• Using evidence from observations to answer an inquiry question about what happens when materials are heated or cooled.

Lesson structure (45 minutes)

1. 0–5 min | Hook and inquiry

• Begin with the inquiry question: “What happens to materials when heated or cooled?”
• Briefly remind students that in this unit we connect changes we can see to heat energy.

2. 5–10 min | Introduction to data collection

• Explain that today students will observe and record changes in materials as they are heated or cooled.
• Introduce the materials to be used (e.g., ice cubes, butter, chocolate) and explain safety and observation expectations.

3. 10–25 min | Observation and recording

• Students observe the materials as they change state (solid, liquid, gas) when heat is applied or removed.
• Students record their observations using drawings and simple notes, noting temperature changes and state changes.
• Teacher circulates to support accurate observations and recording.

4. 25–35 min | Group discussion and data sharing

• Students share their observations with the class.
• Create a class display categorizing observations by state changes (e.g., melting, freezing) and temperature notes.
• Discuss patterns and differences observed.

5. 35–42 min | Science connection and explanation

• Discuss how heat energy causes changes in states of matter.
• Use simple science terms (heat, cool, melt, freeze) to describe the observations.

6. 42–45 min | Exit reflection

• Students respond verbally or in writing to prompts:
  • “When a material is heated it can ___.”
  • “When a material is cooled it can ___.”
• Collect responses to assess understanding of heat and state changes.

Suggested activities

• Hands-on experiments:

  • Provide students with ice cubes to observe melting when exposed to room temperature or warm water.
  • Use simple materials like butter or chocolate to demonstrate melting and solidifying.

• Observation tasks:

  • Have students record changes they see in materials as they heat or cool them, using drawings or simple notes.
  • Encourage students to note the time taken for changes and any differences between materials.

• Group discussions:

  • Facilitate conversations about what happens to materials when heat is added or removed.
  • Ask students to predict what might happen to other materials not tested.
  • Discuss everyday examples of heat changing states, such as ice melting or water boiling.

Resources

• Chart paper or whiteboard divided into categories: car, bus, bike, walk
• Markers and pencils
• Student drawing paper
• Category headings displayed at the front of the classroom
• Optional example images of categorical data displays (no technology required)
• Teacher-prepared observation checklist (informal) for grouping and discussion participation
• Simple sentence starters for exit reflection (e.g., “heated…melt”, “cooled…freeze”)
• Heat/cooling materials for the unit (as required by the investigation routine used in the previous lessons)

Assessment

• Observation: whether students correctly place their drawing into the intended category and can justify their choice.
• Discussion: whether students use “most/fewest” and “more/less” language when interpreting the class display.
• Exit reflection: whether students can name at least one relevant state change linked to heat (melt) and/or cooling (freeze).

Differentiation

• Support:
• Provide pre-labelled picture cards or category cards at a student table for accurate sorting.
• Pair students with a peer who can help them choose the correct category before placing their drawing.
• Model one example aloud (e.g., “My drawing shows a bike, so I place it under ‘bike’.”).
• Extension:
• Ask students to add an extra comparison statement: “I notice that… because…”
• Invite students to suggest reasons why categories may differ (e.g., distance, safety, family routines), connecting pattern to evidence from the display.
• EAL/Diverse learners:
• Use gesture supports (pointing to categories) and sentence starters for discussion and exit reflection.
• Rephrase questions into short steps: “Point to… Which has the most?”
• SEN/Additional needs:
• Offer a reduced drawing task (choose from two prepared options) or allow a partially drawn template with one finishing step.

Extension (optional)

If time and materials allow, students can extend by recording one new observation from the melting/freezing demonstration using a simple drawing plus one word (melt/freeze).