Science (EVS K-5) · Class 3 · Things Around Us · Term 2

Changes We See Around Us

Distinguishing between physical changes (e.g., melting, dissolving) and chemical changes (e.g., burning, rusting) with examples.

• CBSE Learning Outcomes
• NCERT: Class 7, Chapter 6: Physical and Chemical Changes

About This Topic

Changes we see around us introduce students to physical changes, such as melting butter on a warm tawa or dissolving sugar in tea, and chemical changes, like burning a piece of paper or rusting an iron nail left in water. These concepts connect directly to daily observations in Indian homes and kitchens, where children notice ice cream softening in summer heat or milk curdling when lemon juice is added. Students learn to classify changes by asking if the original substance returns and if a new one forms.

In the CBSE Class 3 EVS curriculum under 'Things Around Us' unit, this topic builds skills in observation, prediction, and simple classification. It prepares students for higher classes by developing the ability to describe properties before and after changes, using terms like reversible and irreversible. Hands-on exploration encourages curiosity about everyday science.

Active learning benefits this topic because students handle safe, familiar materials to test predictions, observe outcomes, and discuss results in groups. This approach makes abstract distinctions concrete, boosts retention through sensory experiences, and allows teachers to address individual understandings promptly.

Key Questions

1. What happens to butter or ice cream when you leave it near a warm stove?
2. How is tearing a piece of paper different from burning it?
3. Can you give two examples of changes you see happening in your kitchen every day?

Learning Objectives

• Classify observed changes as either physical or chemical based on whether a new substance is formed.
• Explain the difference between a physical change and a chemical change using examples from the home.
• Identify two reversible changes and two irreversible changes observed in the kitchen.
• Compare the outcomes of tearing paper versus burning paper to distinguish between physical and chemical changes.

Before You Start

Properties of Objects

Why: Students need to be able to observe and describe basic properties like state (solid, liquid) and appearance to notice changes.

States of Matter

Why: Understanding that substances exist as solids, liquids, and gases is fundamental to recognizing changes like melting and evaporation.

Key Vocabulary

Physical Change	A change in the form of a substance, but not its chemical identity. The original substance can often be recovered. Examples include melting ice or tearing paper.
Chemical Change	A change that results in the formation of new chemical substances with different properties. The original substance cannot easily be recovered. Examples include burning wood or rusting iron.
Reversible Change	A change that can be undone, returning the substance to its original state. Melting and freezing are examples of reversible changes.
Irreversible Change	A change that cannot be undone. Once it happens, the substance is permanently altered. Burning and rusting are examples of irreversible changes.
Rusting	A chemical change where iron reacts with oxygen and moisture to form a reddish-brown coating called rust. This weakens the iron.

Watch Out for These Misconceptions

Common Misconception

All changes involving heat are chemical changes.

What to Teach Instead

Students often think melting chocolate or butter involves new substances because of heat, confusing it with burning. Demonstrations comparing melting ice and burning paper show physical changes alter state only. Group discussions after experiments help peers challenge this view and clarify criteria.

Common Misconception

Dissolving salt disappears forever, so it is a chemical change.

What to Teach Instead

Children believe dissolved salt vanishes completely, unlike tearing paper. Stirring and evaporating water reveals the salt returns unchanged. Hands-on trials with tasting or filtering build confidence in reversibility, correcting the idea through direct evidence.

Common Misconception

Tearing paper destroys it like burning, so both are chemical.

What to Teach Instead

Tearing seems permanent to young learners, equated with burning. Rejoining torn pieces or comparing to taped paper shows physical change. Peer prediction sheets before activities reveal and resolve this confusion.

Active Learning Ideas

Stations Rotation: Change Stations

Prepare four stations: melting ice cubes in warm water, dissolving salt in water, tearing and folding paper, and supervised candle burning with adult help. Students predict the type of change, observe for five minutes, record if reversible, and rotate every 10 minutes. End with group sharing of findings.

45 min·Small Groups

Kitchen Changes Observation

In pairs, students watch melting ghee on a tawa, sugar dissolving in warm water, and milk curdling with vinegar. They draw before-and-after sketches and note if the change can reverse. Discuss as a class which are physical and which chemical.

30 min·Pairs

Sorting Game: Reversible Changes

Provide cards with pictures of changes like folding cloth, rusting bicycle, evaporating water, burning matchstick. In small groups, sort into physical and chemical piles, justify choices, then verify with teacher-led demonstration.

25 min·Small Groups

Prediction Walk Around Class

Students walk around the classroom or school, noting changes like wet floor drying or chalk dust settling. Individually predict types, then share in whole class discussion with evidence from observations.

20 min·Whole Class

Real-World Connections

• Chefs and bakers constantly manage physical and chemical changes. For instance, melting butter for a curry is a physical change, but baking a cake involves chemical changes that create new textures and flavours.
• Mechanics and engineers need to understand rusting to prevent corrosion in vehicles and structures. They use protective coatings and select materials that resist this chemical change.
• Everyday cooking involves numerous changes. Boiling water is physical, but curdling milk with lemon juice or frying an egg are chemical changes that alter the food permanently.

Assessment Ideas

Quick Check

Show students pictures of different changes: melting ice, burning candle, tearing cloth, rusting nail, dissolving sugar. Ask them to hold up a green card for physical change and a red card for chemical change. Discuss any disagreements.

Exit Ticket

Give each student a small slip of paper. Ask them to write down one example of a reversible change they saw today and one example of an irreversible change they saw today. Collect these as they leave.

Discussion Prompt

Pose this question: 'Imagine you have a piece of bread. You can toast it, or you can tear it into small pieces. Which of these actions changes the bread into something new? How do you know?' Facilitate a class discussion comparing the two scenarios.

Frequently Asked Questions

What are simple examples of physical and chemical changes for class 3?

Physical changes include melting ice lollies, tearing newspaper, or folding dough. These reverse easily, like refreezing water. Chemical changes are rusting nails in wet soil or burning incense sticks, forming new substances like rust or ash that cannot revert. Use kitchen items like dissolving jaggery or curdling paneer for relatable demos.

How to teach changes around us in CBSE class 3 EVS?

Start with key questions like what happens to ice near a stove. Use observations of daily changes, then classify with charts. Incorporate safe experiments to show reversibility. Reinforce through drawings and group talks to build vocabulary and skills aligned with NCERT standards.

How can active learning help teach physical and chemical changes?

Active learning engages students with hands-on stations for melting, dissolving, and safe burning, letting them predict and observe directly. Group rotations foster discussion, correcting errors on the spot. Tracking changes in journals personalises learning, making distinctions memorable and applicable to home life, far better than lectures.

What are common student mistakes in understanding changes we see?

Pupils mix up dissolving as permanent or think all destructive changes like tearing are chemical. Heat in melting confuses with burning. Address with prediction-observation-reflection cycles in activities, where evidence from senses clarifies reversibility and new substance formation.