Chapter 2 of 13
Chapter 2: What is Long? What is Round?
2D & 3D Shapes, Rolling, Sliding & Surface Properties | CBSE Session 2026–27
Core Pedagogical Competencies & Concepts
- Identifying round objects (spheres, balls, fruits) vs long objects (pencils, bats, rulers).
- Rolling and Sliding: curved surfaces roll, flat surfaces slide.
- Objects that both roll and slide (coins, cylindrical pipes, cans).
- Tower making: flat surfaces stack securely, curved surfaces fall.
- Tracing flat faces of 3D objects to discover 2D shapes (circles, rectangles, squares).
All Textbook Exercises & In-Text Tasks (16 Questions)
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Q1
Textbook Exercise • What is Long, What is Round?
Name two objects from your daily life that are 'Long' and two objects that are 'Round'.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Long objects: Cricket bat, Writing pencil, Ruler.
• Round objects: Cricket ball, Orange, Tomato, Bangle.
• Long objects: Cricket bat, Writing pencil, Ruler.
• Round objects: Cricket ball, Orange, Tomato, Bangle.
CBSE Step-by-Step Marking Scheme
Two correct long objects
1 M
Two correct round objects
1 M
Q2
Textbook Exercise • Blindfold Guessing Game
In Uncle Golu's blindfold game, an object feels smooth, has no corners, and rolls easily in your hands. What is its shape?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
1. An object with no flat corners that rolls in all directions is round (spherical).
2. Example: A tennis ball, marble, or laddoo.
1. An object with no flat corners that rolls in all directions is round (spherical).
2. Example: A tennis ball, marble, or laddoo.
CBSE Step-by-Step Marking Scheme
Identified as round / sphere
1 M
Valid real-life example
1 M
Q3
Let Us Do • Rolling vs Sliding
Classify these 4 objects into 'Rolls' or 'Slides': (a) A glass marble, (b) An eraser, (c) A tomato, (d) A flat wooden ruler.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Rolls: Glass marble and Tomato (curved surfaces).
• Slides: Eraser and Flat wooden ruler (flat surfaces).
• Rolls: Glass marble and Tomato (curved surfaces).
• Slides: Eraser and Flat wooden ruler (flat surfaces).
CBSE Step-by-Step Marking Scheme
Marble & tomato = Rolls
1 M
Eraser & ruler = Slides
1 M
Q4
Let Us Think • Both Rolls and Slides
How can a ₹5 coin both roll and slide? Explain by describing its two positions.
[3 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Slides: Place the coin flat on the table and push it. Its flat circular face slides.
• Rolls: Stand the coin upright on its thin curved edge and gently push. It rolls like a wheel.
• Slides: Place the coin flat on the table and push it. Its flat circular face slides.
• Rolls: Stand the coin upright on its thin curved edge and gently push. It rolls like a wheel.
CBSE Step-by-Step Marking Scheme
Flat face slides
1.5 M
Curved edge rolls
1.5 M
Q5
Hands-on Construction • Making Towers
Can you build a stable tower using round footballs? Why or why not? What objects make good towers?
[3 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
1. No, footballs cannot make a tower because their curved round bodies roll off each other.
2. Objects with flat faces like wooden blocks, books, and matchboxes make stable towers.
1. No, footballs cannot make a tower because their curved round bodies roll off each other.
2. Objects with flat faces like wooden blocks, books, and matchboxes make stable towers.
CBSE Step-by-Step Marking Scheme
Footballs cannot stack because round
1.5 M
Flat objects make stable towers
1.5 M
Q6
Let Us Do • Coin Spinning Trick
Spin a 1-rupee coin on a smooth table like a top. What does the spinning coin look like?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• When a flat round coin spins very fast on its edge, it looks like a round ball (sphere).
• When it stops spinning, it falls flat again.
• When a flat round coin spins very fast on its edge, it looks like a round ball (sphere).
• When it stops spinning, it falls flat again.
CBSE Step-by-Step Marking Scheme
Looks like a round ball / sphere
1 M
Understands spinning illusion
1 M
Q7
Shape Tracing • Matchbox Outline
Keep a matchbox flat on paper and trace its border with a pencil. What flat shape do you get?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• The face of a matchbox has 4 straight sides (opposite sides equal).
• Tracing its border gives a Rectangle.
• The face of a matchbox has 4 straight sides (opposite sides equal).
• Tracing its border gives a Rectangle.
CBSE Step-by-Step Marking Scheme
Identified Rectangle
1 M
Mentions 4 straight sides
1 M
Q8
Shape Tracing • Bangle Outline
Keep a round glass bangle flat on a sheet of paper and draw along its edge. What 2D shape is formed?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• The bangle has a curved circular rim.
• Tracing inside or outside the rim gives a Circle.
• The bangle has a curved circular rim.
• Tracing inside or outside the rim gives a Circle.
CBSE Step-by-Step Marking Scheme
Identified Circle
1 M
Recognized curved border
1 M
Q9
Let Us Think • Can It Roll?
Look at a cylindrical glue stick. Does it roll, slide, or do both?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• A glue stick has a curved round side and flat circular ends.
• Therefore, it both rolls (on its curved side) and slides (on its flat base).
• A glue stick has a curved round side and flat circular ends.
• Therefore, it both rolls (on its curved side) and slides (on its flat base).
CBSE Step-by-Step Marking Scheme
Both rolls and slides
1 M
Explains curved side vs flat end
1 M
Q10
Let Us Do • Sorting Vegetables
Look at: Carrot, Onion, Cucumber, Lemon, Potato. Which are long and which are round?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Long vegetables: Carrot, Cucumber.
• Round vegetables: Onion, Lemon, Potato (mostly round/oval).
• Long vegetables: Carrot, Cucumber.
• Round vegetables: Onion, Lemon, Potato (mostly round/oval).
CBSE Step-by-Step Marking Scheme
Long identified
1 M
Round identified
1 M
Q11
In-Text Prompt • Corner Counting
Does a cricket ball have any sharp corners? How many corners does a square chessboard have?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• A cricket ball has 0 corners (it is completely round).
• A square chessboard has 4 sharp corners.
• A cricket ball has 0 corners (it is completely round).
• A square chessboard has 4 sharp corners.
CBSE Step-by-Step Marking Scheme
Cricket ball = 0 corners
1 M
Chessboard = 4 corners
1 M
Q12
Let Us Do • Cardboard Pipe Challenge
Can you stack hollow cardboard toilet-paper rolls to build a tower? How should they be placed?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• Yes, if placed standing upright on their flat circular rims, they stack into a stable tower.
• If laid on their curved sides, they roll and cannot stack.
• Yes, if placed standing upright on their flat circular rims, they stack into a stable tower.
• If laid on their curved sides, they roll and cannot stack.
CBSE Step-by-Step Marking Scheme
Yes, by standing on flat circular rims
1 M
Curved sides roll
1 M
Q13
Let Us Think • Wheels of a Vehicle
Why are wheels of bicycles, cars, and buses always round and never square?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
1. Round wheels roll smoothly without bumpy stops.
2. Square wheels have 4 corners that would hit the ground and prevent smooth rolling.
1. Round wheels roll smoothly without bumpy stops.
2. Square wheels have 4 corners that would hit the ground and prevent smooth rolling.
CBSE Step-by-Step Marking Scheme
Round wheels roll smoothly
1 M
Square corners prevent rolling
1 M
Q14
Activity • Postcard Tower
Can a thin paper postcard stand upright on a table? How can you fold or roll it so it can hold a book on top?
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
1. A flat postcard bends easily.
2. But if you roll the postcard into a round cylinder (pipe) and tape the ends, it can stand upright and hold a heavy book on top!
1. A flat postcard bends easily.
2. But if you roll the postcard into a round cylinder (pipe) and tape the ends, it can stand upright and hold a heavy book on top!
CBSE Step-by-Step Marking Scheme
Roll into a cylinder / pipe
1 M
Tape ends to make strong column
1 M
Q15
Observation • Match the Pairs
Match the 3D object to its flat face trace: (a) Dice, (b) Water glass bottom, (c) Matchbox side.
[3 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
• (a) Dice → Square
• (b) Water glass bottom → Circle
• (c) Matchbox side → Rectangle
• (a) Dice → Square
• (b) Water glass bottom → Circle
• (c) Matchbox side → Rectangle
CBSE Step-by-Step Marking Scheme
Dice = Square
1 M
Glass = Circle
1 M
Matchbox = Rectangle
1 M
Q16
Summary Drill • Rolls or Slides Summary
Write 'R' for Rolls, 'S' for Slides, and 'B' for Both: (1) Football, (2) Notebook, (3) Candle, (4) Orange.
[2 Marks]
✅ Step-by-Step Solution & Working
Step-by-Step Solution:
1. Football → R (Rolls)
2. Notebook → S (Slides)
3. Candle → B (Both)
4. Orange → R (Rolls)
1. Football → R (Rolls)
2. Notebook → S (Slides)
3. Candle → B (Both)
4. Orange → R (Rolls)
CBSE Step-by-Step Marking Scheme
All 4 classified correctly
2 M
🌟 NEP 2020 Competency-Based Case Study
Playground Slide Experiment
During sports period, Ravi slides his plastic lunchbox down the playground slide, while Priya rolls an orange down the same slide.
Analytical Task: Why does the orange roll while the lunchbox slides? What happens if you push a ₹5 coin down the slide?
Evaluation & Model Answer:
1. The orange has a curved round surface with no flat faces, so it rolls.
2. The lunchbox has flat faces, so it slides.
3. A ₹5 coin can both slide (if placed flat on its face) and roll (if stood upright on its circular edge).
2. The lunchbox has flat faces, so it slides.
3. A ₹5 coin can both slide (if placed flat on its face) and roll (if stood upright on its circular edge).
Rubric: 1.5 M for surface explanation + 1.5 M for coin behavior