is Reduce oil in diet by 10%

’s population Fast f
11.4% of India o
diabetic More than 100 million people diabe od is one o
tics f the
in India are diabetic: ICMR report leading
cause
s of
y and soul
Yoga for the mind, bod
Air pollution is one of the leadi
ng
risk factors for health
Arrival of monsoon lead
s to increase in
malaria and engue cas
es Yoga reduces anxiety and
Diabetes & heart attack are
increase concentration
ns are obese
more
prevalent in people of South

28.6% India
-east
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cases of water
water reduces FIT IN
Safe drinking DIA M
ne diseases OVEM
and vector-bor
Regular handwashing reduces
infection by 50%
Excessive scree
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disease in child ds to dry eye
ren

Air pollution Diet mantra: Reduce the am

ount
is
health emerge a public Increase in screen time in childr
en leads to
and anxiety
of oil and sugar in diet
ncy a rise in obesity, sleep disorders,

media is
into social
Immersion in loneliness
se
spurring ri

Health:
The Ultimate Treasure
3
Probe and ponder
z How does your body respond to an infection such as common cold?
z We rarely see cases of smallpox or polio these days, but diseases
like diabetes and heart problems are more common. Why?
z Could climate change lead to new types of diseases?
z How do emotions like stress or worry affect us and make us sick?
z Why do some groups of people get affected more than others
during disease outbreaks?
z Share your questions

?
28
28 Curiosity — Science
TextbookTextbook
of Science
forfor
Grade
Grade
8 8

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 Chapter 3 — Health: The Ultimate Treasure 29

3.1 Health: Is It More Than Not Falling Sick?

What do the news clippings on the notice board tell you about
people’s health in our country? Is being healthy just about not
having diseases? Health also includes feeling good physically,
staying positive, and having strong relationships. A healthy person
takes care of their body, maintains a positive mindset, and enjoys
social life. Let us now explore what it truly means to be healthy.

Activity 3.1: Let us read

A Grade 8 student moved to a new school in another city. With no
friends in his new environment and busy parents, he felt lonely. To
cope, he spent more time on his phone and social media, but this made
him feel worse. He stopped trying to make friends, had headaches,
lost weight, and could not sleep well. A doctor advised less screen
time and meeting a counsellor. The school counsellor arranged help
to support him in making friends and improving his health.
Think and Reflect: What was the cause of the boy’s health problems?
How did his habits and surroundings affect his well-being?
As per the World Health Organization (WHO), health is
defined as a ‘state of complete physical, mental, and social
Mental
well-being, and not merely the absence of disease’ (Fig. 3.1). A
healthy person can perform various tasks more efficiently and
cope well in different and difficult situations. A healthy person
can adjust well with peer groups and other members of society. Physical Social
Let us understand more about health.
Fig. 3.1: Aspects of
Our scientific heritage
health

Ayurveda teaches us that true health is a balance of body, mind, and

surroundings.
Following dinacharya (daily routine) and
ritucharya (seasonal routine) helps maintain this
balance. Eating fresh, wholesome food suited to
one’s prakriti (body constitution) is essential.
Regular exercise, cleanliness, restful sleep, and
a calm mind support overall well-being. This
can also be achieved through practices like yoga,
meditation, and mindfulness.

3.2 How Can We Stay Healthy?

Staying healthy means eating nutritious food, maintaining
hygiene, staying in a clean place, exercising regularly, getting

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 proper sleep, spending time with family and friends, and having
a positive attitude. What we should do and what should not do to
keep ourselves healthy?

Activity 3.2: Let us list

z List some good habits that your parents, teachers, or elders
often encourage you to follow. How many of these are already
Eat a balanced diet a part of your daily routine? Which ones would you like to
start following? Add to the list below:
{ Keep yourself clean and maintain personal hygiene.
{ Eat a healthy and balanced diet.

{ Exercise regularly.

{ Make time to relax or meditate every day.

z Now, think about habits that are not good for your health.
Add more to the list below:
Stay physically active
{ 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.

Taking care of our body and mind is important. Healthy habits

support a healthy body as well as a healthy mind.
Say no to smoking or Discuss your findings with your friends and teacher. From
alcohol the activity you participated in and the discussions, you may
have realised that our health depends on many factors. These
factors include our lifestyle (how we live) and our environment
(our surroundings).

3.2.1 Maintain a healthy lifestyle

z Eat a balanced diet with plenty of fruits, vegetables, and
whole grains.
Manage stress z Avoid processed, fatty, or sugary food and drinks.
z Stay physically active by playing outdoors, walking, running,
cycling, or exercising.
z Limit screen time and spend more time in nature.
z Get enough sleep to help your body and mind rest and recover.
z Practice yoga or simple breathing exercises like pranayama
regularly.
Get enough sleep
Fig. 3.2: How to be healthy
z Say ‘NO’ to harmful substances things like tobacco, alcohol,
and addictive drugs (Fig. 3.2).

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 Chapter 3 — Health: The Ultimate Treasure 31

3.2.2 Keep the environment clean

Activity 3.3: Let us compare

z Look at Fig. 3.3a and Fig. 3.3b. Which playground would you
like to play in, and why?
z Most of us would like to play in the
playground shown in Fig. 3.3a as it is clean,
well-maintained, and looks beautiful. The
playground in Fig. 3.3b is polluted, dirty,
unhygienic, and full of flies and mosquitoes.
People living in such areas may fall sick
more often.
z In addition to inculcating good habits and
adopting a healthy lifestyle, we must keep
ourselves and our surroundings clean.
(a)
z Have you ever found it hard to breathe in
a place with a lot of smoke or dust? That is
because clean air and water are important
for our health. In cities, air pollution from
vehicles and factories can cause problems
like coughing or asthma. The Air Quality
Index (AQI) helps us know how clean the
air is. A cleaner environment helps us stay
healthy and feel better.
z But health is not only about the body. (b)
Our feelings and relationships matter too. Fig. 3.3: Two different playgrounds
Even if we eat well and live in a clean place,
we may not feel good if we are lonely or upset. Spending
time with friends and family, talking, laughing, and having
fun help keep our minds healthy too.

3.3 How Do We Know That We Are Unwell?

Our body usually works in a certain way to keep us healthy.
When we feel unwell, it means something inside us may not
be working as it should. We may have symptoms, such as pain,
tiredness, or dizziness, and signs like fever, rash, high blood
pressure, or swelling that indicate we are unwell. A symptom
is what we feel (like pain), while a sign is something that can be
seen or measured (like high body temperature when we have
fever). These help doctors understand what might be making us
unwell.

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 3.4 Diseases: What Are the Causes and Types?
A disease is a condition that affects the normal working of the
body or mind. It can happen when one or more organs or organ
systems stop functioning properly. Some diseases are caused by
germs like bacteria, viruses, fungi, worms, or even by protozoa
(single-celled organisms). These disease-causing organisms are
called pathogens. Other diseases may result from poor nutrition
or an unhealthy lifestyle. Some diseases last for a short time, while
others can continue for a long time and need regular treatment
or care. Diseases can be grouped into two major types based on
their causes and how they spread:
Direct contact z Non-communicable
diseases— Some diseases, like
cancer, diabetes, or asthma,
By air
are not caused by pathogens
and do not spread from one
Indirect
contact person to another. They are
Healthy usually linked to lifestyle, diet,
person and/or environment.
z Communicable diseases—
By food
Diseases caused by pathogens
Infected Healthy person are called communicable
person Mosquito insects diseases. They can spread
from one person to
another. Some examples
Rabid animal of communicable diseases
are typhoid, dengue, flu,
Fig. 3.4: Common methods of transmission of diseases chickenpox, and COVID-19.
In recent years, non-communicable diseases (NCDs) like
diabetes, heart disease, and cancer have become more common
in India. This is happening because of changes in how people
live — such as eating more processed food, getting less exercise,
and living longer lives. Today, most deaths in India are caused
by NCDs. Understanding the difference between these two types
helps us know how diseases spread and how to prevent them.
3.4.1 How are communicable diseases caused and spread?
All communicable diseases are caused by pathogens. These
pathogens can enter our body through the air we breathe or by
consuming contaminated food or water and more. But how do
these pathogens spread from one person to another? One common
way is through air, when an infected person coughs or sneezes, or
through direct contact like shaking hands, or indirectly by sharing
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 Chapter 3 — Health: The Ultimate Treasure 33

personal items of an infected person. Some of the communicable

diseases spread through contaminated drinking water or food.
Some pathogens are also spread by insects like mosquitoes and
houseflies — these insects are called vectors (Fig. 3.4).
By understanding how diseases spread, we can take simple
steps to protect ourselves and others. Let us find out how these
communicable diseases spread and how we can prevent them.

Activity 3.4: Let us find out

z Grade 8 students listed some common communicable
diseases in Table 3.1 during a community campaign and a
library survey.
z Check the information listed by referring to books, trusted
websites, or asking your science teacher. Add any missing details.
z Study the table and think about what simple steps can help
prevent each disease.

Table 3.1: Some common communicable diseases affecting

humans

Causal Site of Preventive

Diseases Symptoms
agent infection measures

Diseases spread through the air

Common Virus Respiratory Nasal congestion Washing hands

cold and tract and discharge, frequently, not
influenza sore throat, sharing personal
fever, cough, items, covering the
body ache mouth and nose

Chickenpox Virus Respiratory Mild fever, itchy Complete isolation of

tract, skin skin, rashes, the patient, covering
blisters the mouth and nose,
vaccination

Measles Virus Skin, Fever, sore Isolation of the

respiratory throat, and patient, covering
tract reddish rashes the mouth and nose,
on the neck, ears maintaining good
and other parts hygiene, vaccination
of the skin

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 Tuberculosis Bacteria Lungs Cough, fever, Avoiding close contact
(TB) fatigue, loss of with TB-infected
appetite, night people, covering the
sweats mouth and nose,
maintaining good
hygiene, getting
vaccinated

Diseases spread through contaminated water and food

Hepatitis A Virus Liver Fatigue, fever, Drinking boiled water,

loss of appetite, vaccination
nausea,
vomiting,
jaundice, pain in
the upper right
abdomen

Cholera Bacteria Intestine Diarrhoea and Maintain personal

dehydration hygiene and good
sanitary habits,
consumption of
properly cooked food
and boiled drinking
water, vaccination

Typhoid Bacteria Intestine Headache, Maintain personal

abdominal hygiene and good
discomfort, sanitary habits,
fever, and consumption of
diarrhoea properly cooked food
and boiled drinking
water, vaccination

Ascariasis Worms Intestine Worms in stool, Maintain personal

(roundworms) loss of appetite, hygiene and good
poor growth, sanitary habits,
diarrhoea, consumption of
weight loss, properly cooked food
anaemia and boiled drinking
water

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 Chapter 3 — Health: The Ultimate Treasure 35

Diseases transmitted by insects

Malaria Protozoa Skin, blood High fever, Use of mosquito
profuse nets and repellents,
sweating, wearing long–sleeved
periodic chills clothes, control of
mosquito breeding
in and around your
home

Dengue fever Virus Skin, blood Fever, headache, Use of mosquito

(Break bone muscle and joint nets and repellents,
fever) pain, nausea wearing long-sleeved
clothes, control of
mosquito breeding
in and around your
home, avoiding areas
with still water

By studying the Table 3.1, we can understand how infectious

diseases spread and how to prevent them. Here are some simple
but important precautions:
z Keeping ourselves and our surroundings clean.

z Practising basic hygiene every day.

z Washing hands with soap and water to remove pathogens.
z Covering our mouth and nose while coughing or sneezing.
z Wearing a mask in crowded places provides protection.
z Avoid sharing of personal items like towels
and handkerchiefs. Are diseases always
caused by infections?
z Keeping our home, food, and water clean.
z Staying at home and resting when we are unwell helps the
body recover and minimises spreading the disease to others.
Some infectious diseases are caused by worms that live inside
our bodies, especially in the digestive system. They feed on nutrients
and live as parasites — organisms that live in or on another living
being. These worms usually spread through contaminated food,
water, soil, or contact with infected people or animals.

3.4.2 How are non-communicable diseases caused?

You learnt that non-communicable diseases like cancer, diabetes,
and asthma are linked to lifestyle, diet, and/or environment.
They are the most common cause of death in India. In Grade 6,
you also learnt about diseases like scurvy, anaemia, and goitre,

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 What will happen if I which are caused by a lack of specific nutrients
take excess amount of in the diet. These are called deficiency diseases
Iodine?
and are also non-communicable.
Diseases such as cancer, diabetes, and asthma may often persist
for a long time (more than 3 months) and are referred to as
chronic diseases.
Diabetes is a common disease which is becoming more
prevalent in adults as well as children. In fact, India now has
one of the highest numbers of people with diabetes in the world.
It often develops due to a combination of hormonal imbalances,
unhealthy eating habits, lack of physical activity, being overweight
or obese, and other reasons.
Let us learn more about the causes of non-communicable
diseases and their prevention.

Activity 3.5: Let us survey

z Find out the three most common lifestyle-related diseases in
your neighbourhood
z 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.
z You can also consult trusted health websites, books, teachers
and doctors.
z Fill in Table 3.2 and learn more about lifestyle-related diseases.

Table 3.2: Non-communicable diseases

Name of common Signs and Suggested

S. No.
lifestyle-related diseases symptoms lifestyle change(s)
1. Obesity Eating a balanced
diet and exercising
regularly
2. Diabetes z Frequent
urination
z Excessive thirst
z Weight loss
z Tiredness
z Slow healing
3. High blood pressure
4. ............................ ............................ ............................

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 Chapter 3 — Health: The Ultimate Treasure 37

Be a scientist
Dr. Kamal Ranadive (1917–2001) was a pioneering
biomedical researcher. She studied how hormones
and certain viruses are linked to cancer, helping
improve its treatment and prevention. Her work
also showed how tobacco, diet, and pollution can
raise the risk of cancer, highlighting the importance
of a healthy lifestyle.

3.5 How to Prevent and Control Diseases?

You might have heard the phrase ‘Prevention is better than cure.’
It is important to protect ourselves from both communicable and
non-communicable diseases.

Activity 3.6: Let us read

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? Simple steps like good
sanitation can greatly reduce the spread of communicable diseases.
Find about such community campaigns held in your location. Share
in your class and discuss with your peers about the impact of such
initiatives.
Ability of the body to fight diseases
You would have noticed that some people get sick more frequently
than others, although living in a similar environment. Do you
know why? The natural ability of our body to fight diseases is
known as immunity. Our body has a special system called the
immune system that helps fight against diseases.
You might have taken some drops or injections in your
childhood to protect yourself from certain diseases, such as
polio, measles, tetanus, and hepatitis. These are vaccines that
help prevent serious infections caused by viruses and bacteria.
A vaccine helps our body fight certain diseases by training
the immune system to recognise and attack harmful germs.
providing what is known as acquired immunity — protection
developed after exposure to a pathogen or a vaccine. Vaccines can
be made in different ways — from weakened or dead pathogens
(like viruses or bacteria), or from inactive or harmless parts of
the pathogen. Some newer vaccines instruct our own body cells

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 to make a harmless part of the germ, which our immune system
then learns to fight.
For example, a tetanus shot, often given after an injury
protects against infection by the tetanus-causing bacteria.
It contains an inactivated bacterial toxin that helps the immune
system develop protection without causing the disease.
Do you know when the first vaccine was discovered?
Edward Jenner and the smallpox vaccine
Smallpox was a deadly disease that caused blisters and killed
millions. A milder disease called cowpox, seen in cows, could also
infect humans. In the late 1700s, English doctor Edward Jenner
discovered that people who had cowpox did not get smallpox.
This led to the invention of the first vaccine and helped protect
people from smallpox.

Our scientific heritage

Long before modern vaccines, India had a traditional method called
variolation to protect against smallpox. It involved using material
from a smallpox sore to scratch the skin and create a mild infection
and build immunity. People who performed this practice were known
as teekedaars.

Think like a scientist

Observations
Jenner observed that milkmaids who had
cowpox did not catch smallpox, likely because
the two viruses are related.
Hypothesis
Content in the pus of cowpox blisters protected people from smallpox.

Experimentation
He tested this by injecting cowpox sap into a
boy, who later showed no illness when exposed
to smallpox. Countries reporting
Number of Countries Reporting Cases

smallpox (1950–1980)

1965: Vaccine
campaign
Results
He found that people who were infected 1979:
with cowpox sap were now resistant to Smallpox
eradicated
smallpox.

Application
Mass vaccination eventually helped
eradicate smallpox worldwide.
Year

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 Chapter 3 — Health: The Ultimate Treasure 39

Vaccines are one of the most effective ways to protect people

of all ages — from infants to the elderly — against many serious
diseases. They help prevent illnesses, reduce the spread of
infections, and save millions of lives every year. It is important
to remember that vaccines are preventive, not curative — they
can help minimise serious diseases before they happen, but do
not treat them once someone is already sick. Some people may
fear or doubt vaccines, but scientists and doctors carefully test
them for safety. Getting vaccinated not only protects you but also
the people around you.

Ever heard of ...

India’s Role in Vaccine Production

India is one of the world’s largest vaccine
producers. It manufactures vaccines on a
massive scale and supplies them to many
countries. Indian vaccine companies
played a key role during the COVID-19
pandemic and continue to support global
health efforts.

Be a scientist

Dr. Maharaj Kishan Bhan was a well-known Indian

doctor and scientist. As Secretary of the Department
of Biotechnology, he helped promote science and
innovation in India. He played a key role in developing
the Rotavirus vaccine, which protects children from
diarrhoea. He believed in using research to create
affordable healthcare and made a big difference in
India’s health and biotechnology sectors.

3.5.1 Treatment of diseases

If our immune system fails to protect us against an infectious
disease, we fall ill and need to visit a doctor. The doctor may
give us medicines called antibiotics, which kill the bacteria that
might have caused the disease. Antibiotics work only against
bacterial infections because they target parts of bacterial cells
that are different from human or other animal cells. They do not
work against viruses or diseases caused by protozoa.

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 Think like a scientist
Discovery of the first antibiotic, Penicillin
Penicillin was discovered in 1928 by Alexander Fleming,
a bacteriologist from London. While studying harmful
bacteria, he noticed that a mould on a discarded petri
dish stopped the bacteria from growing. He realized
the mould released a substance that killed the bacteria.
This chance discovery led to the discovery of penicillin,
the first antibiotic used to treat bacterial infections.

Though antibiotics are effective in protecting us against

bacterial infections and have saved millions of lives since their
discovery, their indiscriminate use has led to a decline in their
effectiveness (Fig. 3.5a). Nowadays, there are news headlines
about antibiotic resistance, a phenomenon where bacteria that
were earlier killed by a given antibiotic are found to survive
and multiply despite treatment with that antibiotic. This makes

HOW ANTIBIOTIC RESISTANCE SPREADS IN THE COMMUNITY?

Taking antibiotics when they are not required
Development of Development of
resistance in the resistance in a human
bacteria in animals body

Antibiotics

Exposure
through animal
Spread through food products
soil in a crop field How resistant How resistant May have
manure/animal bacteria spread bacteria spread serious illness
faeces through plants and through humans
and gets care
animal products
at a hospital

Spread
resistant
bacteria to Spread
community directly to
other patients
It reaches human or indirectly
digestive system through through
Patients go Spread in healthcare
crop produce hospital
home workers
through dirty
surface
Fig. 3.5 (a): Spread of antibiotic-resistant bacteria in community
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 Chapter 3 — Health: The Ultimate Treasure 41

common infections harder to treat and increases the risk of

complications, prolonged illness, and even death.

Activity 3.7: Let us infer

z 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?
z To tackle the problem of antibiotic resistance, we must
use antibiotics wisely — only when prescribed by a doctor,
in the correct dose, and for the right duration. Avoiding
unnecessary use helps prevent the rise of resistant bacteria
and keeps antibiotics effective for future generations.
Traditional medicine systems like Ayurveda, Siddha, and Unani
have been used in India for many years to manage common
health problems. They use natural substances like herbs, oils,

HOW BACTERIA BECAME RESISTANT TO ANITBIOTICS?

A few microbes The antibiotic

develop resistance resistant bacteria
to antibiotics. When antibiotics grow and take Some bacteria
kill bacteria causing over. transfer antibiotic
illness, they also resistance to other
kill good bacteria bacteria, causing
protecting the body more problems.
from infection.

I need antibiotic for my Are you giving antibiotics No... No. do not give antibiotic
mother. She has a sore to your cattle? injection to your cattle.
throat and a fever.
tic
io
tib
an

You must get a

prescription from a No. I am not using any It will develop antibiotic
doctor. antibiotics. resistance otherwise.

Fig. 3.5 (b): Development of antibiotic-resistant bacteria and preventive measures

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 and minerals for managing illnesses and promoting recovery,
and focus on a healthy lifestyle and balanced diet. While these
systems can help with some conditions, and are useful for
everyday well-being, they may not be effective for all diseases
and at all stages.
Therapies for non-communicable diseases focus on managing
symptoms and improving quality of life through medication,
lifestyle changes, and rehabilitation. Early diagnosis and
continuous care are key to control the disease progression and
prevent complications.

Snapshots

‹ Health means complete physical, mental, and social well-being — not

just the absence of disease.
‹ Being happy helps us stay active and healthy, and good health also
improves our mood. Health and happiness are closely related.
‹ A disease affects the normal working of the body or mind.
‹ Symptoms are what we feel (like pain or tiredness); signs are what
can be seen or measured (like fever or rash).
‹ Non-communicable diseases like diabetes and heart disease are
caused by lifestyle and environmental factors, not germs. They can
often be prevented with healthy habits, lifestyle changes, and regular
exercise.
‹ Infectious diseases are caused by pathogens like bacteria, viruses, or
worms.
‹ Our immune system helps protect us from harmful pathogens.
‹ Vaccines train the immune system using dead, weakened, or harmless
parts of a germ to prevent disease.
‹ Diagnosis and treatment are important for managing and curing
diseases.

Keep the curiosity alive

1. Group the diseases shown in the images as communicable or

non-communicable.

Cold and flu Typhoid Diabetes Asthma Chickenpox

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 Chapter 3 — Health: The Ultimate Treasure 43

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)
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?
(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?
(iii) How can you protect yourself and others from getting
infected in this situation?
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?
(ii) How can you explain the importance of mosquito nets
or repellents to your sibling?
(iii) What could happen if travellers ignore health advisories
in such areas?
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?
(ii) What would you do if your friend offers you a cigarette
at a party?
(iii) How can schools help prevent students from indulging
in such harmful habits?
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?

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 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
10 12 15 18 22 40
cases

S. No. 7 8 9 10 11 12

Month July August September October November December

No. of dengue
65 65 65 30 30 20
cases
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?
(ii) In which month(s) were the cases lowest?
(iii) What natural or environmental factors during the peak
months might contribute to the increase in dengue cases?
(iv) Suggest a few preventive steps that the community or
government can take before the peak season to reduce
the spread of dengue.
8. Imagine you are in charge of a school health campaign. What
key messages would you use to reduce communicable and
non-communicable diseases?
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?
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.

Prepare some questions based on your

When?
learnings so far ...
Why? Why not?
Where? .....................................................................................
How long?
.....................................................................................
.....................................................................................
44 .....................................................................................
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Curiosity — Textbook of Science for Grade 8

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 Chapter 3 — Health: The Ultimate Treasure 45

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?

Discover, design, and debate

z Students maintain a health diary for at least a month to track

food, hygiene, exercise, sleep, screen time, and emotional
state.
z Read about Indian scientists like Suniti Solomon, Asima
Chatterjee, Dr. Yellapragada Subbarao, Dr. Mary Poonen
Lukose for their contributions in the field of health and
diseases.
z The deadly disease smallpox was eradicated by vaccination.
Society Science
Discover how this was done and why it worked. Debate
whether everyone should be required to get vaccinated to Inter-
protect others. disciplinary
Projects
z 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.
z 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.
z 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.
z Have a debate on ‘Are there ill-effects of fast food on
companion animals?

Reflect on the questions framed by your I

think ... Shouldn’t it
friends and try to answer ... But we be ...
..................................................................................... thought ... Maybe ...

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