Changing Materials: Heating and CoolingActivities & Teaching Strategies
First graders learn best when they can see, touch, and test their ideas in real time. This topic comes to life when students observe materials changing before their eyes, making abstract concepts like reversible and irreversible changes concrete and memorable.
Learning Objectives
- 1Classify materials as having reversible or irreversible changes when heated or cooled.
- 2Explain how adding or removing heat energy causes observable changes in materials.
- 3Compare the effects of heating and cooling on at least three different substances.
- 4Predict the outcome of heating or cooling a given material based on prior investigations.
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Ready-to-Use Activities
Inquiry Circle: Ice Cube Investigation
Small groups receive ice cubes and predict what will happen if the ice is left in a cup on the desk, recording which properties they think will change. They observe over 20 minutes, noting temperature, state, and appearance changes. After the ice melts, they predict what would happen if they could freeze the water again and discuss whether they think this is a reversible change.
Prepare & details
Explain how heating can change the state or properties of a material.
Facilitation Tip: During Ice Cube Investigation, ask students to predict what will happen to the ice when left in the sunlight and then test their predictions by weighing the melted water in the same container.
Setup: Groups at tables with access to source materials
Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template
Gallery Walk: Reversible or Not?
Post photos of eight change events around the room: ice melting, butter melting, wood burning, an egg cooking, chocolate melting, paper tearing, clay being shaped, and bread toasting. Students walk around and for each photo indicate whether they think the change is reversible or not, writing one reason for their choice.
Prepare & details
Compare the effects of heating and cooling on different substances.
Facilitation Tip: During Gallery Walk: Reversible or Not?, model how to use sentence stems like 'I see evidence that this change is reversible because...' to support students in explaining their thinking.
Setup: Wall space or tables arranged around room perimeter
Materials: Large paper/poster boards, Markers, Sticky notes for feedback
Think-Pair-Share: What Changed and Can We Undo It?
Show students a melted crayon that hardened into a new shape. Ask what happened when it was heated, what happened when it cooled, and whether the original crayon still exists in some form. Students pair to construct an explanation, then share with the class. The teacher connects this to reversible changes where material composition has not changed.
Prepare & details
Predict what might happen to a material if it is heated or cooled significantly.
Facilitation Tip: During Think-Pair-Share: What Changed and Can We Undo It?, circulate and listen for students to connect their observations from the Ice Cube Investigation to other materials, such as butter or bread.
Setup: Standard classroom seating; students turn to a neighbor
Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs
Simulation Game: Prediction Chain
The teacher presents a series of heating and cooling scenarios using a photo sequence. Students predict the next state in the sequence, such as what a hot ice cube becomes, what frozen juice becomes when left out, and what melted chocolate becomes when cooled. After predicting each step, students classify the overall change as reversible or requiring more investigation.
Prepare & details
Explain how heating can change the state or properties of a material.
Facilitation Tip: During Simulation: Prediction Chain, pause after each step to ask, 'What do you think will happen next, and why?' to encourage students to connect cause and effect.
Setup: Flexible space for group stations
Materials: Role cards with goals/resources, Game currency or tokens, Round tracker
Teaching This Topic
Teachers should focus on providing varied, hands-on experiences with a range of materials to avoid overgeneralizing changes to just melting or freezing. Avoid leading students toward the idea that all heating causes melting; instead, let their observations guide the discussion. Research shows that young children learn through repetition and comparison, so revisiting reversible and irreversible changes in different contexts deepens understanding and corrects misconceptions.
What to Expect
Students will confidently identify at least three examples of reversible changes and three irreversible changes after these activities. They will use evidence from their investigations to explain why some changes can be undone while others cannot, using clear, kid-friendly language.
These activities are a starting point. A full mission is the experience.
- Complete facilitation script with teacher dialogue
- Printable student materials, ready for class
- Differentiation strategies for every learner
Watch Out for These Misconceptions
Common MisconceptionDuring Ice Cube Investigation, watch for students who assume all materials melt when heated.
What to Teach Instead
Use the investigation to introduce materials like bread or wood, which do not melt but instead burn or harden. Ask, 'What happened to the bread? Can we get the raw dough back? Why or why not?'
Common MisconceptionDuring Gallery Walk: Reversible or Not?, watch for students who assume all changes caused by heating or cooling can be reversed.
What to Teach Instead
Have students compare their ice cube observations to the baked cookie example on the gallery walk. Ask, 'Can you undo baking a cookie? Why or why not?' to prompt discussion about irreversible changes.
Common MisconceptionDuring Ice Cube Investigation, watch for students who think the melted ice cube has disappeared.
What to Teach Instead
Weigh the ice cube before melting and the water after to show the same amount of material remains. Ask, 'Where did the ice go? Is it still here? How do you know?'
Assessment Ideas
After Ice Cube Investigation and Gallery Walk, show students pictures of an ice cube, a chocolate chip, and a piece of toast. Ask them to point to or say whether heating would make it melt or change permanently, and whether cooling would make it freeze or change permanently. Record their responses on a class chart.
After Think-Pair-Share: What Changed and Can We Undo It?, provide students with two index cards. On one card, they draw a picture of something that changes reversibly when heated or cooled. On the other card, they draw something that changes irreversibly. They should label each drawing and explain their choice to a partner before leaving.
During Simulation: Prediction Chain, ask students: 'Imagine you have a stick of butter and a raw egg. If you heat both, what happens? Which change can you undo, and which can you not undo? Why is it important for cooks to know the difference?' Circulate and listen for students to use evidence from their investigations to support their answers.
Extensions & Scaffolding
- Challenge students to design a simple experiment to test whether a crayon melts when heated and then hardens again when cooled, using a hairdryer and ice water.
- Scaffolding: Provide picture cards of materials to sort into reversible and irreversible change groups during the Gallery Walk, or allow students to use real objects if their fine motor skills are still developing.
- Deeper exploration: Introduce the idea of temporary changes, such as a puddle disappearing on a sunny day, and ask students whether this change is reversible or irreversible, and why.
Key Vocabulary
| Heat | Energy that makes things warm. Adding heat can make materials change. |
| Cool | To make something less warm. Removing heat can make materials change. |
| Reversible change | A change that can be undone, like melting ice and then freezing it again. |
| Irreversible change | A change that cannot be undone, like baking a cake or burning paper. |
| Melt | To change from a solid to a liquid because of heat. |
| Freeze | To change from a liquid to a solid because of cooling. |
Suggested Methodologies
Planning templates for Science
5E Model
The 5E Model structures lessons through five phases (Engage, Explore, Explain, Elaborate, and Evaluate), guiding students from curiosity to deep understanding through inquiry-based learning.
Unit PlannerThematic Unit
Organize a multi-week unit around a central theme or essential question that cuts across topics, texts, and disciplines, helping students see connections and build deeper understanding.
RubricSingle-Point Rubric
Build a single-point rubric that defines only the "meets standard" level, leaving space for teachers to document what exceeded and what fell short. Simple to create, easy for students to understand.
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