13 marksCuriosity Grade 8, Chapter 3, Activity 3.3, page 31
Look at Fig. 3.3a and Fig. 3.3b. Which playground would you like to play in, and why? What does this tell you about health?
Hint. The chapter answers its own question, and then draws a conclusion about who falls sick.
The choice. Most of us would choose the playground in Fig. 3.3a, because it is clean, well-maintained and looks beautiful. The playground in Fig. 3.3b is polluted, dirty, unhygienic and full of flies and mosquitos.
Why it is not merely about appearance. The chapter draws the consequence plainly: people living in such areas may fall sick more often. And you can say exactly why, using Table 3.1:
- Mosquitos are vectors for malaria and dengue, and they breed in still water collected in a neglected place
- Houseflies carry pathogens onto food, spreading diseases of the digestive system such as typhoid and cholera
- Dirty surroundings mean contaminated water and poor sanitation, which is how hepatitis A and ascariasis spread
The general conclusion. Alongside good habits and a healthy lifestyle, we must keep ourselves and our surroundings clean. Health is not only what you do to yourself — it is decided partly by where you live.
✦ Answer: the clean, well-maintained playground (Fig. 3.3a) — because the dirty one is full of flies and mosquitos, which are vectors for diseases like malaria, dengue, typhoid and cholera, so people living in such surroundings fall sick more often.
23 marksCuriosity Grade 8, Chapter 3, Section 3.2.2, page 31
Why are clean air and water important for health? What is the Air Quality Index?
Hint. Have you ever found it hard to breathe in a place full of smoke or dust?
Clean air. In cities, air pollution from vehicles and factories can cause problems such as coughing or asthma. The everyday evidence is immediate — it is hard to breathe in a place with a lot of smoke or dust.
Why asthma is the example. Asthma is a non-communicable disease, so it illustrates the chapter's claim that NCDs are linked to lifestyle, diet and/or environment. Nobody catches asthma from another person, but polluted air can trigger and worsen it.
The Air Quality Index (AQI). A measure that helps us know how clean the air is. Its value lets people decide whether outdoor activity is advisable on a given day — which is health information based on a measurement rather than a guess.
Clean water. Equally important, and Table 3.1 shows why: cholera, typhoid, hepatitis A and ascariasis all spread through contaminated drinking water or food. The preventive measure listed against each is the same — boiled drinking water and properly cooked food.
The general statement. A cleaner environment helps us stay healthy and feel better.
✦ Answer: polluted air causes coughing and asthma, and contaminated water spreads cholera, typhoid, hepatitis A and ascariasis; the Air Quality Index (AQI) is a measure that tells us how clean the air is.
33 marksCuriosity Grade 8, Chapter 3, Section 3.2.2, page 31
The chapter says 'health is not only about the body'. Explain what it means, and why eating well and living in a clean place may still not be enough.
Hint. Recall the boy in Activity 3.1 — what was missing from his life?
The claim. "Even if we eat well and live in a clean place, we may not feel good if we are lonely or upset." Physical care handles only one of the three aspects of health.
Why it is not enough. The WHO definition requires physical, mental and social well-being together. A person can have a balanced diet, clean surroundings and no infection, and still be unhealthy — which is exactly the boy in Activity 3.1. He had no disease, but loneliness produced headaches, weight loss and sleeplessness.
What the chapter recommends instead. Spending time with friends and family, talking, laughing and having fun — these "help keep our minds healthy too". Relationships are treated as a health measure, not a luxury.
The two-way link. The Snapshots put it as: being happy helps us stay active and healthy, and good health also improves our mood. The influence runs both ways, which is why neglecting either side eventually damages the other.
A practical consequence. Advice to a person who is unwell should not stop at diet and exercise. For the boy, the effective prescription was less screen time and a counsellor — plus help making friends.
✦ Answer: because health requires mental and social well-being as well as physical — someone with a good diet, clean surroundings and no illness can still be unhealthy if lonely or upset, which is why time with friends and family counts as looking after your health.
43 marksCuriosity Grade 8, Chapter 3, Section 3.3, page 31
How do we know we are unwell? Distinguish clearly between a symptom and a sign, with examples.
Hint. One of them only you can report; the other someone else can check.
The starting point. The body usually works in a certain way. Feeling unwell means something inside may not be working as it should.
The distinction:
| Symptom | Sign |
|---|
| Definition | What we feel | Something that can be seen or measured |
| Who can detect it | Only the patient | Anyone, including a doctor or an instrument |
| The chapter's examples | Pain, tiredness, dizziness | Fever, rash, high blood pressure, swelling |
The test to apply. Ask whether someone else could check it without being told. Nobody can measure your headache — you must report it, so it is a symptom. Anyone can read a thermometer, so fever is a sign.
A subtlety worth noting. Feeling hot is a symptom; a measured high body temperature is a sign. The same illness produces both, and the chapter's own example pairs them exactly this way.
Why doctors need both. Together, signs and symptoms help doctors understand what might be making us unwell — signs give objective evidence, symptoms give information no instrument can supply.
✦ Answer: a symptom is what we feel (pain, tiredness, dizziness) and can only be reported by the patient; a sign is what can be seen or measured (fever, rash, high blood pressure, swelling) and can be checked by someone else — doctors use both to work out what is wrong.
Solutions written by the tuition.in editorial team and checked against NCERT Curiosity - Textbook of Science for Grade 8 (hecu103.pdf), Chapter 3 'Health: The Ultimate Treasure', pages 28-45, Reprint 2026-27. HAND-WRITTEN throughout. Page count verified against the printed contents page (hecu1ps.pdf p.18): 18 pages, 28-45, matching exactly. Covers the 5 'Probe and ponder' prompts (p.28), all 7 activities (3.1-3.7), every in-text section (3.1-3.5.1), both 'Our scientific heritage' boxes (Ayurveda; variolation and teekedaars), both 'Be a scientist' boxes (Kamal Ranadive; Maharaj Kishan Bhan), both 'Think like a scientist' boxes (Jenner; Fleming), the 'Ever heard of' box on India's vaccine production, the 11 numbered 'Keep the curiosity alive' exercises (pp.42-45) and the 5 'Discover, design, and debate' projects (p.45). ALL OF TABLE 3.1 TRANSCRIBED FROM THE PDF rather than from memory - 10 diseases with causal agent, site of infection, symptoms and preventive measures, in the book's own three groupings (air-spread: common cold and influenza, chickenpox, measles, tuberculosis; water- and food-spread: hepatitis A, cholera, typhoid, ascariasis; insect-transmitted: malaria, dengue). Exercise Q7's dengue figures were transcribed and re-read: Jan 10, Feb 12, Mar 15, Apr 18, May 22, Jun 40, Jul 65, Aug 65, Sep 65, Oct 30, Nov 30, Dec 20 - so the three peak months are July, August and September at 65 each and the lowest is January at 10, with the rise beginning in June and the fall in October, which matches the monsoon and is the basis of the answer to (iii). Exercise Q10 was answered by route of transmission using Table 3.1: hepatitis A, poliomyelitis and cholera spread by faecal contamination of water, while tuberculosis and chickenpox are airborne and do not. THREE POINTS OF DELIBERATE CAUTION. (1) The 'could climate change lead to NEW types of diseases' prompt is answered as changing WHERE, WHEN and HOW MUCH existing diseases occur, with the emergence of genuinely new diseases flagged as an open research question rather than asserted. (2) The CPR project answer gives the broad current sequence and India's emergency number 112, but states plainly that CPR is a practical skill that cannot be learnt from a written description, that guidelines are periodically revised, and that it must be learnt hands-on from a qualified instructor - which is what the book itself asks by suggesting a doctor demonstrate a mock drill. (3) The four Indian scientists in the reading project are given as starting points describing the FIELD each worked in, with the student told to verify and cite sources and to note disagreement between them, rather than being handed specific dates and claims to reproduce.. Questions are referenced from the NCERT textbook for identification.
