NCERT Class 9 Science Exploration: Chapter 4 — 4. Describing Motion Around Us
This chapter, '4. Describing Motion Around Us,' from NCERT's Class 9 Science Exploration textbook, delves into the fundamental concepts of movement. It begins by highlighting the ubiquity of motion in nature, from celestial bodies to microscopic particles, and introduces the idea of studying complex motions through simplified models like linear and uniform circular motion. The chapter focuses on linear motion, defining it as movement along a straight line. It emphasizes the importance of a reference point to describe an object's position and distinguish between an object being at rest or in motion. Students will learn to describe motion using numbers, equations, and graphs, moving beyond simple verbal descriptions. This foundational understanding is crucial for comprehending more advanced physics concepts in CBSE curriculum.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 9 |
| Subject | Science |
| Book | Exploration |
| Chapter | Chapter 4 — 4. Describing Motion Around Us |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 477 |
Learning outcomes
- Understand that motion is prevalent in nature.
- Differentiate between linear motion and other types of motion.
- Define and identify a reference point for describing position.
- Distinguish between an object at rest and an object in motion.
- Learn to describe motion using numerical data, equations, and graphs.
Vocabulary
| Word | Meaning |
|---|---|
| 4. Describing Motion Around Us | A change in position of an object with respect to time. |
| Linear motion | 4. Describing Motion Around Us of an object along a straight line. |
| Reference point | A fixed point used to describe the position of an object. |
| Rest | The state of an object when its position does not change with respect to a reference point over time. |
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Practice questions
- What is motion? Answer: 4. Describing Motion Around Us is the change in position of an object with respect to time.
- Give an example of linear motion. Answer: A car moving along a straight highway or a train on a straight track.
- What is needed to describe the position of an object? Answer: A fixed reference point is needed to describe the position of an object.
- When is an object said to be at rest? Answer: An object is said to be at rest if its position with respect to the reference point does not change with time.
Frequently asked questions
What is the main focus of NCERT Class 9 Science Chapter 5?
The chapter focuses on understanding linear motion and how to describe the position and motion of objects using reference points.
What is linear motion?
Linear motion is the movement of an object along a straight line.
Why is a reference point important in describing motion?
A reference point is crucial to determine an object's position and to observe if its position changes over time, indicating motion.
How do scientists study complex motions?
Scientists study complex motions by first analyzing them in simplified, idealized forms like linear or circular motion.
What are the different ways to describe motion mentioned in the chapter?
The chapter states that motion can be described not only in words but also with numbers, equations, and graphs.
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NCERT Class 9 Science — Exploration — Chapter 4 — 4. Describing Motion Around Us. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.