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NCERT Solutions Curiosity Chapter 3 Interdisciplinary projects: Science and Society — Discover, design, and debate

Book page 45 Updated on2026-09-05

Q1.
Students maintain a health diary for at least a month to track food, hygiene, exercise, sleep, screen time, and emotional state.
Answer

Method. Rule a page for each week with the six columns below and fill it in at a fixed time each night — the entry must take under two minutes, or it will not be kept up for a month. Record what actually happened, not what you meant to do; a diary you edit is a diary that teaches you nothing. Keep it private, and at the end of the month look for patterns rather than judging single days.

DateFoodHygieneExerciseSleepScreen timeHow I felt
1 AugBreakfast yes; 1 fruit; 1 packet of chipsHandwash before meals: yes45 min cricket10:30 pm – 6:30 am (8 h)1 h 20 minGood
2 AugBreakfast skipped; 2 cold drinksBath, nails cutNone12:15 am – 6:30 am (6 h)3 hTired, irritable

What to look for at the end of the month. Count, do not guess:

  • How many days did you get 8 hours of sleep? Compare your mood entries on those days with the rest.
  • On days with the most screen time, what was the sleeping time and the mood? This is the link the notice board reports between screen time, sleep disorders and anxiety.
  • How many days did you skip breakfast, and how did you feel in school on those mornings?
  • How many days had at least an hour of physical activity?
  • Draw a simple bar graph of screen time (or sleep) across the month, exactly as you did for Q7. A graph makes a pattern visible that a list of numbers hides.
Tip: the diary is for you, not for marks. Its only purpose is to let you find one habit worth changing, backed by your own evidence rather than by advice.
Q2.
Read about Indian scientists like Suniti Solomon, Asima Chatterjee, Yellapragada Subbarao, Mary Poonen Lukose for their contributions in the field of health and diseases.
Answer

Here is a short note on each, to start you off. Check and add to it from a library book or a trusted website, exactly as Activity 3.4 asked you to do with Table 3.1.

ScientistFieldContribution to health and disease
Suniti SolomonMicrobiology, medicineDetected the first documented cases of HIV infection in India, in Chennai in the mid-1980s, when many refused to believe the disease had reached the country. She went on to build care, counselling and research services for people living with HIV, and worked to remove the stigma attached to them.
Asima ChatterjeeOrganic chemistryStudied the chemistry of medicinal plants of India and the alkaloids they contain. Her work contributed to the development of drugs against epilepsy and malaria, and she was among the first Indian women to be awarded a Doctor of Science.
Yellapragada SubbaraoBiochemistryWorked out how the body stores and uses energy through phosphorus compounds such as ATP, and helped develop medicines for cancer and for filariasis, as well as work leading to the antibiotic tetracycline.
Mary Poonen LukoseMedicine, public healthThe first woman doctor of Travancore and the first woman to be Surgeon General in India. She organised hospitals and services for the treatment of tuberculosis, and for the health of mothers and children.

You may add Kamal Ranadive and Maharaj Kishan Bhan from this chapter itself — she studied how hormones and certain viruses are linked to cancer, and how tobacco, diet and pollution raise the risk of it; he played a key role in developing the Rotavirus vaccine that protects children from diarrhoea.

What the four have in common: none of them worked on disease in the abstract. Each took up a problem that was harming people around them — HIV, malaria, cancer, tuberculosis — which is the same reason the questions in this chapter begin with a news clipping rather than a definition.
Q3.
The deadly disease smallpox was eradicated by vaccination. Discover how this was done and why it worked. Debate whether everyone should be required to get vaccinated to protect others.
Answer

How it was done. After Jenner’s discovery, a worldwide campaign was organised. The graph on page 38 records the result: about 80 countries were reporting smallpox in 1950; the intensified vaccine campaign began in 1965; the number fell steeply through the 1970s; and by 1979 smallpox was eradicated. It remains the only human disease ever wiped out.

Why it worked. Smallpox happened to have every feature that makes eradication possible:

  • The vaccine was effective and could be stored and carried to remote places.
  • The disease produced an unmistakable rash, so every case could be found and reported quickly.
  • The virus infected only human beings — it had nowhere else to hide and wait.
  • Health workers used ring vaccination: when a case was found, everyone around the patient was vaccinated, so the virus could not reach a new body.
  • Countries cooperated and kept it up for more than a decade, including in India.
Why it happens: a pathogen survives only by moving to a new body. Vaccinate enough of the people around each case and every route is closed at once — the chain snaps, and the virus dies out with its last patient.

The debate: should vaccination be compulsory?

For requiring itAgainst requiring it
A vaccine protects not only you but the people around you, as the chapter statesMedical decisions about one’s own body are normally a matter of choice
Some people cannot be vaccinated — newborns, the seriously ill. They are safe only if those around them areA few people genuinely cannot take a particular vaccine, so no rule can be absolute
Eradication needs very high coverage; a few unprotected pockets let the disease returnCompulsion can increase suspicion; persuasion may achieve more coverage than a rule
Some fear or doubt vaccines, but scientists and doctors carefully test them for safetyInformation and access must come first — many miss vaccines because no centre is nearby, not because they refuse

A defensible position: free access, clear information and active outreach should come first, because most gaps are gaps in access rather than in willingness; requirements for entry to school or hospital work are reasonable where a disease is dangerous and spreads easily, with genuine medical exemptions allowed. Argue your own side, but argue it with the graph and the figures, not with opinion alone.

Q4.
According to current guidelines, learn the correct sequence of steps for performing cardiopulmonary resuscitation (CPR) on an adult in case of sudden stoppage of breathing. School may invite a doctor or a professional to demonstrate a mock drill.
Answer

Read this as an outline of the sequence, not as training. CPR is a physical skill. Learn it by practising on a manikin under a doctor or a certified trainer, exactly as the book suggests — a mock drill in school is the right way.

The current sequence for an adult, in order:

  1. Check that the scene is safe — for you and for the person. You cannot help anyone if you are hurt too.
  2. Check for response. Tap the shoulders firmly and ask loudly, “Are you all right?”
  3. Shout for help and call for an ambulance at once (112 in India), or ask a specific person by name to call and to bring an AED if one is available. Put the phone on speaker so you can keep your hands free.
  4. Check breathing for no more than about 10 seconds. Gasping is not normal breathing.
  5. If there is no normal breathing, begin chest compressions. Place the heel of one hand at the centre of the chest, the other hand on top, keep your arms straight and your shoulders above your hands, and push hard and fast — about 100 to 120 compressions a minute, about 5 cm deep, letting the chest come back fully between compressions.
  6. If you are trained and willing, give 2 rescue breaths after every 30 compressions. If you are not trained, give compressions only and do not stop.
  7. Use the AED as soon as it arrives, and follow its spoken instructions exactly.
  8. Continue without stopping until the person starts breathing normally, a trained responder takes over, or you are physically unable to continue. If someone else is present, change over every two minutes so that neither of you tires.
Why it works: when the heart stops, the blood stops moving, and the brain begins to be damaged within minutes. Chest compressions push the heart from outside and keep some blood — and therefore some oxygen — moving to the brain until the heart can be restarted. Every minute without compressions makes survival less likely, which is why starting quickly matters more than starting perfectly.
Ask the doctor at the drill: how do I know it is cardiac arrest and not fainting? How deep is 5 cm really? What do I do if I hear a rib crack? What is different for a child or an infant?
Q5.
Invite a doctor to the school. Students may be encouraged to interact with the doctor on the issues of malnutrition, under-nutrition, and over-nutrition.
Answer

Prepare before the visit. Send the doctor the topic in advance, collect written questions from every class so that shy students are also heard, and appoint two students to take notes and one to thank the guest. Keep the discussion about the conditions, never about any individual in the room.

The three terms, so that you can follow the discussion:

TermWhat it meansWhat it can lead to
MalnutritionThe diet does not supply nutrients in the right amounts — the general term that covers both of the othersThe body cannot work or grow normally
Under-nutritionToo little food, or too little of some nutrientPoor growth, tiredness, low resistance to infection, and the deficiency diseases learnt in Grade 6 — scurvy, anaemia, goitre
Over-nutritionMore energy taken in than the body uses, often with too much oil, sugar and salt but still short of some nutrientsObesity, and a higher chance of diabetes and heart disease later

Questions worth asking the doctor:

  • Can a person be over-nourished and still be short of iron or vitamins at the same time?
  • What does a genuinely balanced plate look like for a student of our age, using foods available in our market?
  • Which deficiency do you see most often in children here, and what is the cheapest way to correct it?
  • Why does the same diet affect two people differently?
  • How is anaemia detected, and what should a student do if they are always tired?
  • What should we not do — which popular diet advice do you wish students would ignore?
Note: discuss all three as health conditions with many causes — the food available at home, family income, illness, hormones and activity all play a part. The chapter itself lists several causes side by side. Nobody’s body should be discussed as a personal failure.
Q6.
If you are given an opportunity to create a health card, what all would you like to include in it. Create your own health card and have discussion about it.
Answer

A health card should hold what a doctor would need in a hurry, and what you need in order to keep track over time. Keep it to one page.

SectionWhat to includeWhy it is needed
IdentityName, age, date of birth, class, address, blood groupBlood group is the first thing asked in an emergency
Emergency contactsParent or guardian, family doctor, nearest hospital, ambulance numberSaves minutes when minutes matter
Growth recordHeight and weight, measured on the same date each termA single reading says little; the trend says a lot
Vaccination recordEvery vaccine taken, with the date; the next one dueVaccines are preventive — a missed date is the whole problem
Allergies and long-term conditionsAllergies to any medicine or food; asthma, diabetes or other chronic condition; medicines taken regularlyPrevents a dangerous mistake in treatment
Illness historyMajor illnesses, hospital stays, surgeries, with datesHelps a new doctor understand the pattern
Check-upsDates of eye test, dental check-up, general check-up and their findingsProblems such as weak eyesight are found only if looked for
Daily habitsUsual sleeping hours, physical activity, screen timeThese are the causes behind most non-communicable diseases
Well-beingA place to note if you have been feeling low, anxious or lonely, and whom you can talk toHealth is physical, mental and social — Activity 3.1 showed why this belongs on the card
Discuss in class: who should be allowed to see this card? Most classes conclude that the student, the parents, the doctor and the school nurse should — and no one else. A health record is private information, and that principle is worth agreeing on before the cards are made.
Q7.
Have a debate on ‘Are there ill-effects of fast food on companion animals?’
Answer

The motion is a question, so the debate should be settled by evidence rather than by feeling. The honest answer is yes — fast food does harm companion animals, and for two separate reasons.

Reason 1: too much of the wrong nutrients. Fast food is high in oil, salt and sugar. A dog or a cat is far smaller than an adult human, so the same piece of pizza or samosa is a very large share of its daily energy. Regularly fed such food, pets become overweight, which brings on the same kind of trouble the chapter describes in people — breathlessness, joint pain and a shorter, less comfortable life. Sudden fatty meals can also inflame the pancreas, and soft, sugary food damages teeth and gums.

Reason 2: some human foods are actively poisonous to animals. This is the part many people do not know. Chocolate, onion and garlic, grapes and raisins, and the sweetener xylitol are all dangerous to dogs — not merely unhealthy. A pet cannot read a label, so the responsibility is entirely ours.

For the motion (there are ill-effects)Against the motionReply
Excess oil, salt and sugar cause obesity and digestive illness in pets“A small piece now and then does no harm”True for a rare treat of safe food; the harm comes from a routine, and from the fact that “small” for us is large for a 10 kg animal
Several common human foods are toxic to dogs and cats“Street animals eat leftovers and survive”Surviving is not being healthy — and it is exactly these animals that are seen at shelters with digestive disease
Pets cannot choose or refuse; the keeper decides“Pet food is expensive”Plain cooked rice, dal, curd, boiled vegetables and clean water cost little and are safer than fast food
How to run the debate well: ask each side to bring one source — a veterinary doctor’s advice, a pet-care book, or a trusted website — and to name it while speaking. Invite the local veterinarian to judge. A debate in which both sides quote a source teaches more than one in which both sides only feel strongly.
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