Are Changes Permanent ?

Content Standards

In this lesson, we will learn about different types of changes around us — physical and chemical — and how to identify reversible and irreversible changes.

Performance Standards

Students will understand:

The difference between physical and chemical changes.
How to identify reversible and irreversible changes.
The conditions necessary for rusting, combustion, and crystallization.
Types of changes in daily life (slow/fast, desirable/undesirable, natural/man-made).

Alignment Standards

Reference: NCERT Book Alignment

The lesson is aligned with the NCERT Grade 7 Science Book-Chapter 5: Changes Around Us: Physical and Chemical

Section 5.5- Are Changes Permanent?

Learning Objectives

By the end of the lesson, students will be able to:

Differentiate between physical and chemical changes.
Recognize reversible and irreversible changes.
Understand mixed changes (both physical & chemical).
Explain rusting and its prevention.
Describe combustion and crystallization.
Classify changes as natural, fast/slow, desirable/undesirable.
Apply the concepts to daily life situations.

Prerequisites (Prior Knowledge)

Some changes happen naturally (day and night, weather).
Objects can change in shape, size, and state.
Some changes (like melting) can be reversed, while others (like burning paper) cannot.

Introduction

In our daily life, we observe several changes — ice melts, paper burns, food gets cooked, milk curdles, iron rusts. Some changes are temporary, while some are permanent. This chapter helps students to classify these changes as physical or chemical, reversible or irreversible, and understand their role in nature and everyday life.

Timeline (40 Minutes)

Title	Approximate Duration	Procedure	Reference Material
Engage	5	Show gif from PPT and ask students How can we tell if something has truly changed, or if it’s just pretending to be different? Do you think the original material is still there? Or it is just looking different. Has it completely changed into something new? What makes you think that?”	Slides
Explore	10	Virtual Lab Challenge students to find examples of physical and chemical changes in their everyday lives, beyond the classroom examples. Which of these changes can be reversed: melting ice, burning paper, or burning a candle? Which changes seemed easy to reverse? Is it possible to get paper back after burning? Why or why not? How is melting ice different from burning paper?	Slides and VR lab
Explain	10	Physical Change Chemical Change Reversible vs. Irreversible Changes Evidence of Chemical Change (gas, heat/light, color, precipitate)	Slides and Virtual Lab
Evaluate	10	Students will attempt the Self-Evaluation task on LMS.	Virtual Lab
Extend	5	Scenario-Based Learning: It’s the year 2050, and humans have established a colony on Mars. What physical and chemical changes would occur in the materials used to build habitats in such a harsh environment? In the year 2055, doctors use advanced technology to heal injuries instantly. What chemical changes occur in the body during this process, and how do they differ from traditional healing methods?	Slides

Are Changes Permanent ?

Introduction

In our daily life, we see many changes happening around us. Ice melts into water, milk turns sour, paper burns, iron rusts, or clay is shaped into a pot. But have you ever wondered — are these changes permanent or temporary?

All changes can be grouped mainly into two types:

Physical changes – where only the form or appearance changes.
Chemical changes – where a new substance is formed.

Some changes can be reversed (temporary), while others are permanent.

Theory

1. Physical Change

A physical change only changes the physical properties like shape, size, color, or state of matter.
No new substance is formed.
These changes are usually reversible.

Examples:

Melting of ice → water → freezing back to ice.
Dissolving sugar in water.
Cutting paper into pieces.

2. Chemical Change

A chemical change produces a new substance with different properties.
Heat, light, sound, or gas may be released.
These changes are usually irreversible.

Examples:

Burning of paper → turns to ash and smoke.
Rusting of iron.
Cooking of food.
Spoiling milk.

3. Are All Changes Permanent?

Physical changes are usually temporary and reversible.
Chemical changes are generally permanent and irreversible.
However, some changes may not fit neatly (example: condensation of steam is reversible, but burning wood is not).

Comparison: Physical vs. Chemical Change

Feature	Physical Change	Chemical Change
New Substance Formed	No	Yes
Reversible	Usually yes	Usually no
Energy Involved	Often small (heating/cooling)	Often large (heat, light, sound released)
Examples	Melting ice, boiling water, dissolving salt	Burning, rusting, digestion of food

Applications in Daily Life

Physical Changes:

Freezing water to make ice cubes.
Shaping clay into toys.
Sharpening a pencil.

Chemical Changes:

Cooking vegetables.
Burning candles.
Making curd from milk.
Rust prevention methods (painting, oiling).

Vocabulary

This is the list of vocabulary terms used throughout the lesson.

Physical Change :A change where no new substance is formed, only appearance/state changes.
Chemical Change:A change that produces a new substance with different properties.
Reversible: A change that can be undone to get the original substance back.
Irreversible :A change that cannot be undone.
Rusting :Formation of reddish-brown flaky substance (iron oxide) on iron due to oxygen and moisture.
Combustion :Burning of a substance in the presence of oxygen to produce heat and light.
Evaporation :Process by which liquid changes into vapor.
Condensation: Process by which vapor cools to form liquid.

Are Changes Permanent ?

Introduction

Welcome to the interactive learning module on Reversible and Irreversible Changes. This activity is designed to help students understand how some changes around us can be undone, while others cannot. Through engaging 3D animations, definitions, and real-life examples, learners will explore the difference between reversible and irreversible changes in an easy and memorable way.

Key Features

Interactive Menu: Students can choose between Reversible and Irreversible change modules.
3D Animations: Realistic visualizations of ice melting/freezing and paper burning.
Step-by-Step Interaction: Students click buttons to initiate and observe changes.
Comparative Understanding: Both types of changes are clearly contrasted.
Quiz Section: MCQs at the end reinforce learning and check understanding.
Reset Option: Allows restarting the activity anytime for revision.

Step-by-Step Procedure for VR Experience

Step 1: Enter the Virtual Lab

Students are welcomed with three buttons: Reversible, Irreversible, and Reset.
Clicking on any option begins the respective activity.

Step 2: Exploring Reversible Changes.

Students click on Reversible to see its definition.
A button labelled Ice to Water appears.
On clicking, a 3D animation shows ice melting into water.
Next, they click Water to Ice to see water freezing back into ice.
Next/Reload options allow them to move forward or repeat this activity.

Step 3: Exploring Irreversible Changes

Students click on Irreversible to see its definition.
An animation of burning paper is shown, demonstrating that the change cannot be undone.
Next/Reload options are available here too.

Step 4: Self-Evaluation Quiz

After exploring both types of changes, students attempt a quiz with MCQs.
The quiz checks their ability to identify reversible and irreversible changes.

Step 5: Reset Option

At any time, students can click Reset to return to the main menu and restart the experience.