Chapter 6: Changes around us
These NCERT Class 6 Science Chapter 6 notes explain the concept of change and how changes take place all around us in daily life. The chapter introduces students to different types of changes based on nature, speed, and reversibility.
NCERT Class 6 Science Chapter 6 – Changes Around Us helps students understand reversible and irreversible changes, physical and chemical changes, and changes caused by heating and cooling. Simple examples like melting of ice and rusting of iron make the concepts easy to grasp.
This chapter builds a strong base for understanding scientific processes and prepares students for future topics in physics and chemistry.
1. Meaning of change
- A change means something that does not remain the same
- Changes happen all around us in daily life
- Changes occur all the time, knowingly or unknowingly
- Changes can be seen in objects, materials, and living beings
- Milk turning into curd is a common example of change
2. Types of changes
- Changes can be classified on different bases
- Some changes can be reversed, while others cannot
- Some changes are physical, others are chemical
- Changes can be slow or fast
- Changes can be periodic or non-periodic
3. Reversible and irreversible changes
- A reversible change can be changed back to its original form
- Melting of ice is a reversible change
- Stretching of a rubber band is a reversible change
- An irreversible change cannot be reversed
- Burning of paper and cooking food are irreversible changes
4. Physical changes
- A physical change involves change in shape, size, or state
- No new substance is formed in physical change
- Physical changes are usually reversible
- Cutting wood is a physical change
- Melting wax and breaking glass are physical changes
5. Chemical changes
- In a chemical change, a new substance is formed
- Chemical changes are usually irreversible
- Properties of substances change completely
- Rusting of iron is a chemical change
- Burning of coal and digestion of food are chemical changes
6. Changes due to heating and cooling
- Heating causes expansion of materials
- Heating can cause melting of solids
- Heating can cause evaporation of liquids
- Cooling causes contraction of materials
- Water changes into ice on cooling
7. Expansion and contraction
- Most materials expand on heating
- Materials contract on cooling
- Expansion increases the size of materials
- Contraction decreases the size of materials
- This property is important in daily life uses
8. Slow and fast changes
- Slow changes take a long time to happen
- Rusting of iron is a slow change
- Growth of plants is a slow change
- Fast changes happen quickly
- Burning of a matchstick is a fast change
9. Periodic and non-periodic changes
- Periodic changes occur at regular intervals
- Day and night is a periodic change
- Seasons are periodic changes
- Non-periodic changes do not occur regularly
- Earthquake and flood are non-periodic changes
10. Importance of this chapter
- Helps understand changes in daily life
- Explains different types of changes clearly
- Builds foundation for chemistry and physics
- Develops scientific thinking
- Important for NCERT, BPSC, and UPSC foundation
11. Important keywords and definitions
- Change: A process in which something does not remain the same
- Reversible change: A change that can be changed back to original form
- Irreversible change: A change that cannot be reversed
- Physical change: A change in which no new substance is formed
- Chemical change: A change in which a new substance is formed
- Expansion: Increase in size on heating
- Contraction: Decrease in size on cooling
- Periodic change: A change that occurs at regular intervals
Understanding NCERT Class 6 Science Chapter 6 is important to recognise how materials change in form, shape, and properties. The chapter helps students connect science concepts with everyday observations.
The ideas discussed in Changes Around Us form the foundation for learning about chemical reactions, heat, and matter in higher classes.
Continue reading NCERT Class 6 Science Chapter 7 – Getting to Know Plants to understand living organisms and plant structure.
FAQs
Q1. What is change according to NCERT Class 6 Science Chapter 6?
A change means something that does not remain the same.
Q2. What is a reversible change?
A reversible change is a change that can be changed back to its original form.
Q3. What is an irreversible change?
An irreversible change is a change that cannot be reversed.
Q4. What is the difference between physical and chemical change?
In a physical change no new substance is formed, while in a chemical change a new substance is formed.
Q5. Why is this chapter important for exams?
It explains basic ideas of change, useful for school exams and BPSC foundation.