What did Dhruv and Meera observe about some paper boats?

Some floated while others flipped

Can a heavy object float in water?

Never — heavy objects always sink

Yes — floating or sinking also depends on shape not just weight

What is the main factor explored in the floating and sinking activities?

The weight and shape of the object

Why does aluminium foil float when spread out but sink when made into a ball?

Because it is lighter as a ball

Because the shape changes its ability to displace water — spread out it displaces more water and floats but as a ball it displaces less and sinks

Because balls are always heavier

Because water is repelled by flat surfaces

What does the spinning experiment show about the relationship between shape and visual appearance?

Shape has no effect on appearance

When spun a non-circular shape like a square can appear circular because of the visual effect of rapid rotation

All shapes appear square when spun

What can you change in a spinner to observe different results?

Its shape colour position of hole and size

Why is it important to first guess whether an object will float or sink before testing it in the activity?

To make the activity more competitive

To develop scientific thinking by comparing predictions with actual results to learn from differences

Name two objects that can float based on the chapter's examples.

An empty plastic bottle with a lid and aluminium foil spread out

What did the chapter say about the connection between shape and floating?

Shape has no effect on floating

Shape plays a major role in floating — the same material can float or sink depending on its shape

Only material determines floating

Only weight determines floating

Compare how a flat aluminium foil floats and a ball-shaped aluminium foil sinks. What scientific principle does this demonstrate?

The same material can float or sink depending on its shape because shape determines how much water is displaced — this is a basic principle of buoyancy

What is the scientific reason why differently coloured sections of a spinning disc appear to blend together?

The eye cannot process the individual colours fast enough at high speed so they appear merged or blended

Based on the experiments in the chapter what conclusion can you draw about the relationship between prediction and scientific observation?

Making predictions before experiments and comparing them to actual results helps develop scientific thinking and understanding

Why is it important for students to make their boats different from others in the classroom activity?

So students can compare different designs and learn which shapes and materials work best for floating

So the activity is more colourful

So students don't copy each other

The chapter says objects can float or sink based on their shape. How would you test whether shape truly affects floating without changing any other variable?

Use different materials and shapes

Use the same material (like aluminium foil) in different shapes (flat ball cup) and test each in water changing only the shape

Use different sizes of the same shape

What is the relationship between balance and the shape of a spinner? How does the position of the centre hole affect performance?

The hole position does not matter

A spinner with the hole exactly at the centre rotates symmetrically and stays upright while one with an off-centre hole becomes unbalanced and wobbles because the weight is unevenly distributed

Larger holes always make spinners spin better

A student finds that a clay boat floats but a clay ball sinks. What does this tell us about the role of shape in buoyancy?

Clay is a special material that sometimes floats

The boat shape allows clay to displace more water creating enough upward force to float while the ball shape displaces less water and cannot support its own weight

Design a simple experiment to test whether the colour pattern on a spinner affects how it looks when spinning. What would you change and what would you keep the same?

Change the shape of the spinner and keep colour the same

Keep the spinner shape and size the same change only the colour pattern and observe how the colours appear when spinning compared to when still

Only change the speed of spinning

What does the chapter's exploration of everyday objects (boats spinners fans) teach us about science?

Science is only for laboratories

Scientific principles are present in everyday objects and can be understood and tested through simple hands-on experiments with readily available materials

Science cannot be done by children

All experiments require expensive equipment

NCERT Solutions Class 4 Environment Chapter 7 – How Things Work

Name: How Things Work – Class 4 Environment
Uploaded: 2026-07-22T23:44:53+00:00
Description: Meera and Dhruv explore how things around us work by spinning spinners and making paper boats. They learn how shape and balance affect movement and floating, discovering the science behind everyday objects.

Class 4 Environment

Last Updated: 22 July 2026

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Chapter Introduction

Meera and Dhruv explore how things around us work by spinning spinners and making paper boats. They learn how shape and balance affect movement and floating, discovering the science behind everyday objects.

हिंदी में (Hindi)

मीरा और ध्रुव घूमते हुए स्पिनर और कागज की नावें बनाकर हमारे आस-पास की चीज़ों के काम करने के तरीके को खोजते हैं। वे सीखते हैं कि आकार और संतुलन गति और तैरने को कैसे प्रभावित करते हैं, और रोजमर्रा की वस्तुओं के पीछे की विज्ञान को समझते हैं|

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Important Points

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Practice MCQ Questions (25 questions)

Q1. What did Meera observe when she spun a coin?

Q2. Which spinner stays upright and spins properly?

Q3. What happens when a square card spinner is spun?

Q4. What did Meera and Dhruv make from old newspapers during the rain?

Q5. Name one everyday object that spins.

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Frequently Asked Questions (FAQ)

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NCERT Solutions Class 4 Environment Chapter 7 – How Things Work

Chapter Introduction

Watch Video Lecture

Important Points

Practice MCQ Questions (25 questions)

Q1. What did Meera observe when she spun a coin?

Q2. Which spinner stays upright and spins properly?

Q3. What happens when a square card spinner is spun?

Q4. What did Meera and Dhruv make from old newspapers during the rain?

Q5. Name one everyday object that spins.

Q6. What did Dhruv and Meera observe about some paper boats?

Q7. Can a heavy object float in water?

Q8. What happens to aluminium foil when it is made into a ball and dropped in water?

Q9. What is the main factor explored in the floating and sinking activities?

Q10. Give one example of a boat material mentioned in the chapter.

Q11. Why does aluminium foil float when spread out but sink when made into a ball?

Q12. What does the spinning experiment show about the relationship between shape and visual appearance?

Q13. What can you change in a spinner to observe different results?

Q14. Why is it important to first guess whether an object will float or sink before testing it in the activity?

Q15. Name two objects that can float based on the chapter's examples.

Q16. What did the chapter say about the connection between shape and floating?

Q17. Compare how a flat aluminium foil floats and a ball-shaped aluminium foil sinks. What scientific principle does this demonstrate?

Q18. What is the scientific reason why differently coloured sections of a spinning disc appear to blend together?

Q19. Based on the experiments in the chapter what conclusion can you draw about the relationship between prediction and scientific observation?

Q20. Why is it important for students to make their boats different from others in the classroom activity?

Q21. The chapter says objects can float or sink based on their shape. How would you test whether shape truly affects floating without changing any other variable?

Q22. What is the relationship between balance and the shape of a spinner? How does the position of the centre hole affect performance?

Q23. A student finds that a clay boat floats but a clay ball sinks. What does this tell us about the role of shape in buoyancy?

Q24. Design a simple experiment to test whether the colour pattern on a spinner affects how it looks when spinning. What would you change and what would you keep the same?

Q25. What does the chapter's exploration of everyday objects (boats spinners fans) teach us about science?

Frequently Asked Questions (FAQ)

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