NCERT Solutions for Class 7 Science Chapter 1: The Ever-Evolving World of Science – Curiosity

Chapter 1 of the Class 7 NCERT Curiosity textbook is titled “The Ever-Evolving World of Science”. It’s a short orientation chapter that frames science as an ongoing process of curiosity, questioning and exploration rather than a fixed set of facts — using everyday examples like paper planes, ripening fruit, haldi stains, and shadows to introduce ideas that are explored more deeply in later chapters. These Class 7 Science Chapter 1 solutions are also useful as quick revision notes before exams.

Below are original, independently checked solutions to the chapter’s genuine in-text questions and activity, sourced from the textbook’s actual content.

In-Text Questions

Q1. How do things work?
Solution: Things work because of how their different parts or materials interact with each other. In a clock, gears turn together to show the time; in a plant, roots absorb water that travels up to help it grow; in an electric bulb, electricity flowing through a filament makes it glow. Our own bodies work similarly, with each organ playing a specific role. Science helps us understand how these parts work together to make things function.

Q2. Why do events happen the way they do?
Solution: Events happen due to cause and effect — every action or condition leads to a result. For example, rain falling makes the ground wet because the rain directly causes that change. Recognising these patterns, conditions and rules is what lets science explain and even predict why certain events occur.

Q3. What can we learn from patterns we see in nature?
Solution: Patterns in nature help us understand how things work, how changes happen over time, and let us predict future events. The changing seasons follow a regular yearly pattern, so we know roughly when to expect spring or winter; the way plants grow and animals behave also follows patterns that reveal their life cycles. Studying these patterns helps us make better decisions and understand the world more clearly.

Q4. Why are some fruits sour?
Solution: Some fruits are sour because they contain natural acids, such as citric acid. How much acid a fruit contains, and how ripe it is, affects how sour it tastes — for example, lemons are sour due to high citric acid content, while fruits like green mangoes become less sour (sweeter) as they ripen and their acid content changes.

Q5. What happens when we wash a haldi (turmeric) stain on our uniform with soap?
Solution: Soap is basic (alkaline) in nature. When soap comes into contact with a haldi stain, it reacts chemically with the turmeric’s natural pigment (curcumin), which is sensitive to pH — this reaction turns the yellow stain reddish, which can actually make the stain more visible and harder to remove with soap alone (using an acidic rinse, like diluted lemon water, tends to work better on haldi stains for this reason).

Activity: Question the Answer

This chapter includes a fun “Question the Answer” activity, where students are given an answer and must come up with a sensible question for it — the reverse of a normal quiz.
Example 1. Answer given: “Just add some milk.” — A fitting question: “What should I do if my coffee is too strong?”
Example 2. Answer given: “Because the cat’s teeth were crooked.” — A fitting question: “Why did my cat have trouble chewing its food?”
Example 3. Answer given: “Don’t panic, I have my towel.” — A fitting question: “What should I do? I forgot to bring my bathrobe.”
Example 4 (numeric). Answer given: “42.” — A fitting question: “If a box contains 6 sets of books, and each set has 7 books, how many books are in the box?” (Check: 6×7 = 42. ✓)
This activity flips the usual question→answer direction to encourage students to think about how a single answer could arise from many different questions — reinforcing that curiosity and creative thinking are as central to science as finding “the” correct answer.

Themes Previewed in This Chapter

This orientation chapter briefly touches on ideas that are explored fully in later Class 7 Science chapters, including: testing whether materials conduct electricity (using batteries, lamps and wires); the difference between changes that can be reversed (like melting ice) and permanent changes (like a fruit ripening or a rock breaking); how heat can speed up changes; the basic life processes animals need to survive (eating, breathing, circulating nutrients); how plants make their own food through photosynthesis; how studying light and shadows explains day, night and eclipses; and how science connects discovery with responsibility toward nature and society.

Why This Chapter Matters

This chapter sets the tone for the entire Class 7 Curiosity textbook: science is framed as an active process of observing, questioning and exploring — not just memorising facts. The everyday examples used here (sour fruits, haldi stains, paper planes) reappear in more depth as motivating questions for the chemistry, biology and physics chapters that follow.

More on This Chapter

See also: Class 7 Science NCERT Book (Curiosity) and the Class 7 Science Formulas Handbook.

Related pages: Extra Questions for Class 7 Science Chapter 1 | Revision Notes for Class 7 Science Chapter 1

Frequently Asked Questions

Q: Does this chapter have a full “Figure it Out” exercise like later chapters?
A: No — like the equivalent Class 8 orientation chapter, this is a short introductory chapter built around a handful of in-text questions and one activity, rather than a full end-of-chapter exercise with many numbered questions.

Q: Why does the chapter ask about a haldi stain and sour fruits before teaching any chemistry?
A: These are used as motivating, everyday “wonder” questions to show that ordinary kitchen observations connect to real scientific ideas (acid-base chemistry, in this case) that will be explained properly in later chapters — the goal here is sparking curiosity, not teaching the full explanation yet.

Written by Satish

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