Class 8 › Science › Curiosity Health: The Ultimate Treasure Class 8 Science · Curiosity · Chapter 3
Practice all → Summary Questions & answers Practise this chapter → View all Page 1 free about 8 min read , Full kit about 55 min read Page 1 free about 8 min read , Full kit about 55 min read View all 6 amazing Marks Booster kits → This chapter treats health as far more than the absence of disease. Following the World Health Organization, it defines health as a state of complete physical, mental, and social well-being. Staying healthy depends on lifestyle and environment: eating a balanced diet, exercising, sleeping well, limiting screen time, keeping surroundings clean, and avoiding harmful substances like tobacco and alcohol. The chapter distinguishes symptoms (what we feel, such as pain) from signs (what can be seen or measured, such as fever). Diseases are grouped as non-communicable, which are linked to lifestyle, diet, or environment and do not spread (such as diabetes, asthma, and cancer), and communicable, caused by pathogens and able to spread (such as typhoid, dengue, and influenza). Pathogens spread through air, water, food, direct contact, and vectors like mosquitoes. The body fights disease using its immune system. Vaccines provide acquired immunity by training the immune system with weakened, dead, or harmless parts of a germ; Edward Jenner developed the first vaccine against smallpox, and India long practised variolation. Antibiotics treat bacterial infections only, and their misuse causes antibiotic resistance, so they must be used wisely. Prevention through hygiene, sanitation, balanced diet, and timely vaccination is emphasised.
Health
A state of complete physical, mental, and social well-being, not merely the absence of disease.
Pathogen
A disease-causing organism such as a bacterium, virus, fungus, protozoan, or worm.
Communicable disease
A disease caused by pathogens that can spread from one person to another, such as flu or typhoid.
Non-communicable disease
A disease linked to lifestyle, diet, or environment that does not spread between people, such as diabetes.
Vaccine
A preparation that trains the immune system to recognise and fight a germ, giving acquired immunity.
Antibiotic resistance
The ability of bacteria to survive and multiply despite treatment with an antibiotic that once killed them.
Q1 How does the WHO define health? Answer Q2 What is the difference between a symptom and a sign? Answer Q3 How do communicable and non-communicable diseases differ? Answer Q4 Name four ways pathogens can spread. Answer Q5 What is immunity and which body system provides it? Answer Q6 How does a vaccine protect us? Answer Q7 Who discovered the first vaccine, and against which disease? Answer Q8 Why do antibiotics not work against the common cold or flu? Answer Q9 What is antibiotic resistance and how can it be reduced? Answer Q10 Why is vaccination described as preventive and not curative? Answer Q1 How does your body respond to an infection such as common cold? Answer Q2 We rarely see cases of smallpox or polio these days, but diseases like diabetes and heart problems are more common. Why? Answer Q3 Could climate change lead to new types of diseases? Answer Q4 How do emotions like stress or worry affect us and make us sick? Answer Q5 Why do some groups of people get affected more than others during disease outbreaks? Answer Q6 Share your questions Answer Q1 Think and Reflect: What was the cause of the boy's health problems? How did his habits and surroundings affect his well-being? Answer Q1 List some good habits that your parents, teachers, or elders often encourage you to follow. How many of these are already a part of your daily routine? Which ones would you like to start following? Add to the list below: Keep yourself clean by maintaining personal hygiene. Eat a healthy and balanced diet. Exercise regularly. Make time to relax or meditate every day. Answer Q2 Now, think about habits that are not good for your health. Add more to the list below: Spending too much time on mobile phones or other digital screens. Eating fast food and other junk food every day. Sleeping very late or not getting enough sleep. Skipping meals, especially breakfast. Answer Q1 Look at Fig. 3.3a and Fig. 3.3b. Which playground would you like to play in, and why? Answer Q2 Have you ever found it hard to breathe in a place with a lot of smoke or dust? Answer Q1 Grade 8 students listed some common communicable diseases in Table 3.1 during a community campaign and a library search. Answer Q2 Check the information listed by referring to books, trusted websites, or asking your science teacher. Add any missing details. Answer Q3 Study the table and think about what simple steps can help prevent each disease. Answer Q1 Find out the three most common lifestyle-related diseases in your neighbourhood Answer Q2 Talk to a doctor, nurse, health worker or even a family member who knows about health and what kind of lifestyle changes can help prevent or manage these diseases. Answer Q3 You can also consult trusted health websites, books, teachers and doctors. Answer Q4 Fill in Table 3.2 and learn more about lifestyle-related diseases. Table 3.2: Non-communicable diseases S. No. Name of common lifestyle-related diseases Signs and symptoms Suggested lifestyle change(s) 1. Obesity Eating a balanced diet and exercising regularly 2. Diabetes Frequent urination Excessive thirst Weight loss Tiredness Slow healing 3. High blood pressure 4. ............................ ............................ ............................ Answer Q1 Odisha — community-led sanitation campaign In Bhadrak district, Odisha, a community sanitation campaign helped more people build and use toilets. This reduced open defecation significantly, and improved child health, with fewer cases of diarrhoea and infections. What do you infer from this case study? Answer Q2 Find about such community campaigns held in your location. Share in your class and discuss with your peers about the impact of such initiatives. Answer Q1 Study the infographic given in Fig. 3.5b. How do you think the antibiotic resistance has been developed in bacterial pathogens? What precautions may be taken to reduce antibiotic resistance? Answer Q1 1. Group the diseases shown in the images as communicable or non-communicable. Cold and flu Typhoid Diabetes Asthma Chickenpox Answer Q2 2. Diseases can be broadly grouped into communicable and non-communicable diseases. From the options given below, identify the non-communicable diseases. (i) Typhoid (ii) Asthma (iii) Diabetes (iv) Measles (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv) Answer Q3 3. There is a flu outbreak in your school. Several classmates are absent, while some are still coming to school coughing and sneezing. (i) What immediate actions should the school take to prevent further spread? Answer Q4 3. There is a flu outbreak in your school. Several classmates are absent, while some are still coming to school coughing and sneezing. (ii) If your classmate, who shares the bench with you, starts showing symptoms of the flu, how can you respond in a considerate way without being rude or hurtful? Answer Q5 3. There is a flu outbreak in your school. Several classmates are absent, while some are still coming to school coughing and sneezing. (iii) How can you protect yourself and others from getting infected in this situation? Answer Q6 4. Your family is planning to travel to another city where malaria is prevalent. (i) What precautions should you take before, during, and after the trip? Answer Q7 4. Your family is planning to travel to another city where malaria is prevalent. (ii) How can you explain the importance of mosquito nets or repellents to your sibling? Answer Q8 4. Your family is planning to travel to another city where malaria is prevalent. (iii) What could happen if travellers ignore health advisories in such areas? Answer Q9 5. Your uncle has started smoking just to fit in with his friends, even though it is well known that smoking can seriously harm health and even cause death. (i) What would you say to him to make him stop, without being rude? Answer Q10 5. Your uncle has started smoking just to fit in with his friends, even though it is well known that smoking can seriously harm health and even cause death. (ii) What would you do if your friend offers you a cigarette at a party? Answer Q11 5. Your uncle has started smoking just to fit in with his friends, even though it is well known that smoking can seriously harm health and even cause death. (iii) How can schools help prevent students from indulging in such harmful habits? Answer Q12 6. Saniya claims to her friend Vinita that “Antibiotics can cure any infection, so we don’t need to worry about diseases.” What question(s) can Vinita ask her to help Saniya understand that her statement is incorrect? Answer Q13 7. The following table contains information about the number of dengue cases reported in a hospital over a period of one year: S. No. 1 2 3 4 5 6 Month January February March April May June No. of dengue cases 10 12 15 18 22 40 S. No. 7 8 9 10 11 12 Month July August September October November December No. of dengue cases 65 65 65 30 30 20 Make a bar graph of the number of cases on the Y-axis and the month on the X-axis. Critically analyse your findings and answer the following: (i) In which three months were the dengue cases highest? Answer Q14 7. The following table contains information about the number of dengue cases reported in a hospital over a period of one year: Make a bar graph of the number of cases on the Y-axis and the month on the X-axis. Critically analyse your findings and answer the following: (ii) In which month(s) were the cases lowest? Answer Q15 7. The following table contains information about the number of dengue cases reported in a hospital over a period of one year: Make a bar graph of the number of cases on the Y-axis and the month on the X-axis. Critically analyse your findings and answer the following: (iii) What natural or environmental factors during the peak months might contribute to the increase in dengue cases? Answer Q16 7. The following table contains information about the number of dengue cases reported in a hospital over a period of one year: Make a bar graph of the number of cases on the Y-axis and the month on the X-axis. Critically analyse your findings and answer the following: (iv) Suggest a few preventive steps that the community or government can take before the peak season to reduce the spread of dengue. Answer Q17 8. Imagine you are in charge of a school health campaign. What key messages would you use to reduce communicable and non-communicable diseases? Answer Q18 9. It is recommended that we should not take an antibiotic for a viral infection like a cold, a cough, or flu. Can you provide the possible reason for this recommendation? Answer Q19 10. Which disease(s) among the following may spread if drinking water gets contaminated by the excreta from an infected person? Hepatitis A, Tuberculosis, Poliomyelitis, Cholera, Chickenpox. Answer Q20 11. When our body encounters a pathogen for the first time, the immune response is generally low but on exposure to the same pathogen again, the immune response by the body is much more compared to the first exposure. Why is it so? Answer Q1 Students maintain a health diary for at least a month to track food, hygiene, exercise, sleep, screen time, and emotional state. Answer 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 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 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 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 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 Q7 Have a debate on ‘Are there ill-effects of fast food on companion animals? Answer
How does the WHO define health?
A Complete physical, mental, and social well-being B Being physically strong only C Only the absence of any disease D Having no symptoms at all
Flashcards & interactive practice 
