Class 7 Science Chapter 6 NCERT Book - Adolescence: A Stage of Growth and Change

 Page 1


Adolescence:  
A Stage of Growth 
and Change
6
The journey of a plant generally begins with the germination of a 
seed. With proper nourishment, the seed becomes a sapling and 
matures into a young plant. This journey is marked by some specific 
changes. Some of the visible changes are an increase in its height, the 
appearance of more leaves, and the development of flowers, fruits, 
and new seeds. From these seeds, new plants emerge.
It is quite unlikely that a seedling will develop the capabilities 
to produce its own seeds immediately after germination. It needs 
to grow and reach maturity to become capable of producing 
seeds. Similarly, animals also need to grow and reach maturity 
before they can reproduce. Some animals lay eggs that hatch 
into young ones, while others, like humans, directly give birth to 
young ones. In both cases, the young ones gradually grow in size 
and develop over time.
Chapter 6.indd   73 Chapter 6.indd   73 04-04-2025   04:25:25 04-04-2025   04:25:25
Page 2


Adolescence:  
A Stage of Growth 
and Change
6
The journey of a plant generally begins with the germination of a 
seed. With proper nourishment, the seed becomes a sapling and 
matures into a young plant. This journey is marked by some specific 
changes. Some of the visible changes are an increase in its height, the 
appearance of more leaves, and the development of flowers, fruits, 
and new seeds. From these seeds, new plants emerge.
It is quite unlikely that a seedling will develop the capabilities 
to produce its own seeds immediately after germination. It needs 
to grow and reach maturity to become capable of producing 
seeds. Similarly, animals also need to grow and reach maturity 
before they can reproduce. Some animals lay eggs that hatch 
into young ones, while others, like humans, directly give birth to 
young ones. In both cases, the young ones gradually grow in size 
and develop over time.
Chapter 6.indd   73 Chapter 6.indd   73 04-04-2025   04:25:25 04-04-2025   04:25:25
Curiosity | Textbook of Science | Grade 7
74
The journey of life of a human can be divided into different 
stages—infancy, childhood, adolescence, adulthood, and old age. 
Each person experiences these stages at their own pace, and the 
duration of each stage may vary from one individual to another. 
From infancy to adulthood, our bodies undergo various changes. 
Until around 10–12 years of age, most changes are related to 
height and weight. After this, other noticeable changes begin to 
occur, marking the onset of adolescence. This is a period of rapid 
growth and development, typically occurring between the ages 
of 10–19. During adolescence, the body prepares for adulthood.
Humans, like most other living beings, can not reproduce 
immediately after their birth. Their bodies need to grow and 
reach a stage of maturity to be able to reproduce.
As humans grow and develop, they experience significant 
physical, emotional, and behavioural changes, along with the 
ability to reproduce. Some of these changes may be quite clearly 
observable, while others occur internally and may go unnoticed. 
In this chapter, you will explore adolescence, understand its 
importance, and learn how to handle it with a sense of responsibility.
6.1 Growing With Age: The Teenage Years
During the summer vacation, Venkatesh visited his grandparents. 
As he entered the house, his 12-year-old cousin, Devyani came 
running to greet him.
You have become 
so tall, Devyani!
Your voice has 
also changed!
Venkatesh, you 
have a thin 
moustache now!! 
Let us try to understand this interesting conversation 
between Venkatesh and Devyani.
Activity 6.1: Let us discuss
 ? Take a jar and some paper slips.
 ? Write down the changes you can notice among students as 
they go from Grades 5 to 8. These could be related to height, 
strength, behaviour, or any other aspect. Please avoid writing 
names on the slips.
Chapter 6.indd   74 Chapter 6.indd   74 04-04-2025   04:25:27 04-04-2025   04:25:27
Page 3


Adolescence:  
A Stage of Growth 
and Change
6
The journey of a plant generally begins with the germination of a 
seed. With proper nourishment, the seed becomes a sapling and 
matures into a young plant. This journey is marked by some specific 
changes. Some of the visible changes are an increase in its height, the 
appearance of more leaves, and the development of flowers, fruits, 
and new seeds. From these seeds, new plants emerge.
It is quite unlikely that a seedling will develop the capabilities 
to produce its own seeds immediately after germination. It needs 
to grow and reach maturity to become capable of producing 
seeds. Similarly, animals also need to grow and reach maturity 
before they can reproduce. Some animals lay eggs that hatch 
into young ones, while others, like humans, directly give birth to 
young ones. In both cases, the young ones gradually grow in size 
and develop over time.
Chapter 6.indd   73 Chapter 6.indd   73 04-04-2025   04:25:25 04-04-2025   04:25:25
Curiosity | Textbook of Science | Grade 7
74
The journey of life of a human can be divided into different 
stages—infancy, childhood, adolescence, adulthood, and old age. 
Each person experiences these stages at their own pace, and the 
duration of each stage may vary from one individual to another. 
From infancy to adulthood, our bodies undergo various changes. 
Until around 10–12 years of age, most changes are related to 
height and weight. After this, other noticeable changes begin to 
occur, marking the onset of adolescence. This is a period of rapid 
growth and development, typically occurring between the ages 
of 10–19. During adolescence, the body prepares for adulthood.
Humans, like most other living beings, can not reproduce 
immediately after their birth. Their bodies need to grow and 
reach a stage of maturity to be able to reproduce.
As humans grow and develop, they experience significant 
physical, emotional, and behavioural changes, along with the 
ability to reproduce. Some of these changes may be quite clearly 
observable, while others occur internally and may go unnoticed. 
In this chapter, you will explore adolescence, understand its 
importance, and learn how to handle it with a sense of responsibility.
6.1 Growing With Age: The Teenage Years
During the summer vacation, Venkatesh visited his grandparents. 
As he entered the house, his 12-year-old cousin, Devyani came 
running to greet him.
You have become 
so tall, Devyani!
Your voice has 
also changed!
Venkatesh, you 
have a thin 
moustache now!! 
Let us try to understand this interesting conversation 
between Venkatesh and Devyani.
Activity 6.1: Let us discuss
 ? Take a jar and some paper slips.
 ? Write down the changes you can notice among students as 
they go from Grades 5 to 8. These could be related to height, 
strength, behaviour, or any other aspect. Please avoid writing 
names on the slips.
Chapter 6.indd   74 Chapter 6.indd   74 04-04-2025   04:25:27 04-04-2025   04:25:27
Adolescence: A Stage of Growth and Change
75
 ? Fold the slips and place them in the jar.
 ? Mix all the slips received from the students in the class and 
unfold the collected slips one by one. Based on the information 
on the slips, discuss the changes with the students in the class.
What were the most commonly observable changes among 
students, as mentioned on the slips? List these in Table 6.1.
Height 1.
2.
3.
4.
Weight and strength
Appearance
…
Changes Your observations S.No.
Table 6.1: Most common changes during growing up
Have you also experienced some of these changes? If yes, then 
it is because you are also reaching this stage gradually. This stage 
starts around 10 years of age and can continue up to the age of 
19. It is usually a stage of development between childhood and 
adulthood, and is called adolescence.
While analysing Table 6.1, you might have noticed the following:
Changes in body structure, weight gain, and 
strength
As boys grow, it might be seen that along with growing 
taller, they gain weight, their shoulders might become 
a bit broader, and their chests may get wider.
 Girls also undergo changes in height and weight, 
and other body changes like development of breasts. 
Increase in height
From birth, our body undergoes continuous growth 
and development including an increase in height. 
However, the increase in height becomes more 
prominent during adolescence.
Chapter 6.indd   75 Chapter 6.indd   75 04-04-2025   04:25:30 04-04-2025   04:25:30
Page 4


Adolescence:  
A Stage of Growth 
and Change
6
The journey of a plant generally begins with the germination of a 
seed. With proper nourishment, the seed becomes a sapling and 
matures into a young plant. This journey is marked by some specific 
changes. Some of the visible changes are an increase in its height, the 
appearance of more leaves, and the development of flowers, fruits, 
and new seeds. From these seeds, new plants emerge.
It is quite unlikely that a seedling will develop the capabilities 
to produce its own seeds immediately after germination. It needs 
to grow and reach maturity to become capable of producing 
seeds. Similarly, animals also need to grow and reach maturity 
before they can reproduce. Some animals lay eggs that hatch 
into young ones, while others, like humans, directly give birth to 
young ones. In both cases, the young ones gradually grow in size 
and develop over time.
Chapter 6.indd   73 Chapter 6.indd   73 04-04-2025   04:25:25 04-04-2025   04:25:25
Curiosity | Textbook of Science | Grade 7
74
The journey of life of a human can be divided into different 
stages—infancy, childhood, adolescence, adulthood, and old age. 
Each person experiences these stages at their own pace, and the 
duration of each stage may vary from one individual to another. 
From infancy to adulthood, our bodies undergo various changes. 
Until around 10–12 years of age, most changes are related to 
height and weight. After this, other noticeable changes begin to 
occur, marking the onset of adolescence. This is a period of rapid 
growth and development, typically occurring between the ages 
of 10–19. During adolescence, the body prepares for adulthood.
Humans, like most other living beings, can not reproduce 
immediately after their birth. Their bodies need to grow and 
reach a stage of maturity to be able to reproduce.
As humans grow and develop, they experience significant 
physical, emotional, and behavioural changes, along with the 
ability to reproduce. Some of these changes may be quite clearly 
observable, while others occur internally and may go unnoticed. 
In this chapter, you will explore adolescence, understand its 
importance, and learn how to handle it with a sense of responsibility.
6.1 Growing With Age: The Teenage Years
During the summer vacation, Venkatesh visited his grandparents. 
As he entered the house, his 12-year-old cousin, Devyani came 
running to greet him.
You have become 
so tall, Devyani!
Your voice has 
also changed!
Venkatesh, you 
have a thin 
moustache now!! 
Let us try to understand this interesting conversation 
between Venkatesh and Devyani.
Activity 6.1: Let us discuss
 ? Take a jar and some paper slips.
 ? Write down the changes you can notice among students as 
they go from Grades 5 to 8. These could be related to height, 
strength, behaviour, or any other aspect. Please avoid writing 
names on the slips.
Chapter 6.indd   74 Chapter 6.indd   74 04-04-2025   04:25:27 04-04-2025   04:25:27
Adolescence: A Stage of Growth and Change
75
 ? Fold the slips and place them in the jar.
 ? Mix all the slips received from the students in the class and 
unfold the collected slips one by one. Based on the information 
on the slips, discuss the changes with the students in the class.
What were the most commonly observable changes among 
students, as mentioned on the slips? List these in Table 6.1.
Height 1.
2.
3.
4.
Weight and strength
Appearance
…
Changes Your observations S.No.
Table 6.1: Most common changes during growing up
Have you also experienced some of these changes? If yes, then 
it is because you are also reaching this stage gradually. This stage 
starts around 10 years of age and can continue up to the age of 
19. It is usually a stage of development between childhood and 
adulthood, and is called adolescence.
While analysing Table 6.1, you might have noticed the following:
Changes in body structure, weight gain, and 
strength
As boys grow, it might be seen that along with growing 
taller, they gain weight, their shoulders might become 
a bit broader, and their chests may get wider.
 Girls also undergo changes in height and weight, 
and other body changes like development of breasts. 
Increase in height
From birth, our body undergoes continuous growth 
and development including an increase in height. 
However, the increase in height becomes more 
prominent during adolescence.
Chapter 6.indd   75 Chapter 6.indd   75 04-04-2025   04:25:30 04-04-2025   04:25:30
Curiosity | Textbook of Science | Grade 7
76
Changes in voice
In adolescent boys, the growth of the voice box leads 
to a voice that sounds hoarse. The voice box is a 
structure in our throat that helps us to speak. The 
growth may be seen as a bump in the throat region 
and is called the Adam’s apple. However, it is not 
noticeable in every individual. The voice box also 
grows in adolescent girls but it is not as big as in the 
boys, leading to only slight changes in voice. 
Changes in facial skin: emergence of pimples
Another common occurrence during the adolescent 
years is a skin condition called acne, in which small, 
reddish pimples appear. These are commonly visible 
on the face. Acne occurs due to an increase in oily 
secretions from the skin during adolescence that can 
clog the skin pores and lead to infections. While acne 
is a condition, pimples are a manifestation of it.
Appearance of hair in different parts of body
Both boys and girls experience the growth of hair in 
different parts of their bodies, such as the armpits and 
pubic region. 
 Boys often develop facial hair, which later grows 
into a moustache and a beard as they move towards 
adulthood. Some boys may also develop chest hair and 
back hair, though few boys may have no significant 
hair growth. Variations in and timing of appearance of 
hair growth is completely normal.
A key point to remember
Whether it is a change in height, voice, or facial hair, it is 
important to recognise that the timing, nature, and extent 
of these changes vary among individuals. These variations 
are completely normal.
 Each person experiences adolescence at his or her 
own pace, and its duration also varies from one person to 
another.
Adam's 
apple
Chapter 6.indd   76 Chapter 6.indd   76 04-04-2025   04:25:32 04-04-2025   04:25:32
Page 5


Adolescence:  
A Stage of Growth 
and Change
6
The journey of a plant generally begins with the germination of a 
seed. With proper nourishment, the seed becomes a sapling and 
matures into a young plant. This journey is marked by some specific 
changes. Some of the visible changes are an increase in its height, the 
appearance of more leaves, and the development of flowers, fruits, 
and new seeds. From these seeds, new plants emerge.
It is quite unlikely that a seedling will develop the capabilities 
to produce its own seeds immediately after germination. It needs 
to grow and reach maturity to become capable of producing 
seeds. Similarly, animals also need to grow and reach maturity 
before they can reproduce. Some animals lay eggs that hatch 
into young ones, while others, like humans, directly give birth to 
young ones. In both cases, the young ones gradually grow in size 
and develop over time.
Chapter 6.indd   73 Chapter 6.indd   73 04-04-2025   04:25:25 04-04-2025   04:25:25
Curiosity | Textbook of Science | Grade 7
74
The journey of life of a human can be divided into different 
stages—infancy, childhood, adolescence, adulthood, and old age. 
Each person experiences these stages at their own pace, and the 
duration of each stage may vary from one individual to another. 
From infancy to adulthood, our bodies undergo various changes. 
Until around 10–12 years of age, most changes are related to 
height and weight. After this, other noticeable changes begin to 
occur, marking the onset of adolescence. This is a period of rapid 
growth and development, typically occurring between the ages 
of 10–19. During adolescence, the body prepares for adulthood.
Humans, like most other living beings, can not reproduce 
immediately after their birth. Their bodies need to grow and 
reach a stage of maturity to be able to reproduce.
As humans grow and develop, they experience significant 
physical, emotional, and behavioural changes, along with the 
ability to reproduce. Some of these changes may be quite clearly 
observable, while others occur internally and may go unnoticed. 
In this chapter, you will explore adolescence, understand its 
importance, and learn how to handle it with a sense of responsibility.
6.1 Growing With Age: The Teenage Years
During the summer vacation, Venkatesh visited his grandparents. 
As he entered the house, his 12-year-old cousin, Devyani came 
running to greet him.
You have become 
so tall, Devyani!
Your voice has 
also changed!
Venkatesh, you 
have a thin 
moustache now!! 
Let us try to understand this interesting conversation 
between Venkatesh and Devyani.
Activity 6.1: Let us discuss
 ? Take a jar and some paper slips.
 ? Write down the changes you can notice among students as 
they go from Grades 5 to 8. These could be related to height, 
strength, behaviour, or any other aspect. Please avoid writing 
names on the slips.
Chapter 6.indd   74 Chapter 6.indd   74 04-04-2025   04:25:27 04-04-2025   04:25:27
Adolescence: A Stage of Growth and Change
75
 ? Fold the slips and place them in the jar.
 ? Mix all the slips received from the students in the class and 
unfold the collected slips one by one. Based on the information 
on the slips, discuss the changes with the students in the class.
What were the most commonly observable changes among 
students, as mentioned on the slips? List these in Table 6.1.
Height 1.
2.
3.
4.
Weight and strength
Appearance
…
Changes Your observations S.No.
Table 6.1: Most common changes during growing up
Have you also experienced some of these changes? If yes, then 
it is because you are also reaching this stage gradually. This stage 
starts around 10 years of age and can continue up to the age of 
19. It is usually a stage of development between childhood and 
adulthood, and is called adolescence.
While analysing Table 6.1, you might have noticed the following:
Changes in body structure, weight gain, and 
strength
As boys grow, it might be seen that along with growing 
taller, they gain weight, their shoulders might become 
a bit broader, and their chests may get wider.
 Girls also undergo changes in height and weight, 
and other body changes like development of breasts. 
Increase in height
From birth, our body undergoes continuous growth 
and development including an increase in height. 
However, the increase in height becomes more 
prominent during adolescence.
Chapter 6.indd   75 Chapter 6.indd   75 04-04-2025   04:25:30 04-04-2025   04:25:30
Curiosity | Textbook of Science | Grade 7
76
Changes in voice
In adolescent boys, the growth of the voice box leads 
to a voice that sounds hoarse. The voice box is a 
structure in our throat that helps us to speak. The 
growth may be seen as a bump in the throat region 
and is called the Adam’s apple. However, it is not 
noticeable in every individual. The voice box also 
grows in adolescent girls but it is not as big as in the 
boys, leading to only slight changes in voice. 
Changes in facial skin: emergence of pimples
Another common occurrence during the adolescent 
years is a skin condition called acne, in which small, 
reddish pimples appear. These are commonly visible 
on the face. Acne occurs due to an increase in oily 
secretions from the skin during adolescence that can 
clog the skin pores and lead to infections. While acne 
is a condition, pimples are a manifestation of it.
Appearance of hair in different parts of body
Both boys and girls experience the growth of hair in 
different parts of their bodies, such as the armpits and 
pubic region. 
 Boys often develop facial hair, which later grows 
into a moustache and a beard as they move towards 
adulthood. Some boys may also develop chest hair and 
back hair, though few boys may have no significant 
hair growth. Variations in and timing of appearance of 
hair growth is completely normal.
A key point to remember
Whether it is a change in height, voice, or facial hair, it is 
important to recognise that the timing, nature, and extent 
of these changes vary among individuals. These variations 
are completely normal.
 Each person experiences adolescence at his or her 
own pace, and its duration also varies from one person to 
another.
Adam's 
apple
Chapter 6.indd   76 Chapter 6.indd   76 04-04-2025   04:25:32 04-04-2025   04:25:32
Adolescence: A Stage of Growth and Change
77
Now, we have understood some of the changes that take place 
during adolescence, particularly those that are easily observable. 
Some of these characteristic changes, like change in voice, the growth 
of facial and chest hair in boys, and the development of breasts 
in girls are not directly involved in the process of reproduction. 
However, these characteristic changes help distinguish males 
from females. For this reason, they are called secondary sexual 
characteristics.
Secondary sexual characteristics are natural signs that the 
body is preparing for adulthood. They mark the onset of puberty. 
Puberty is the stage in which the body of an adolescent undergoes 
external and internal changes to develop into an adult capable of 
reproduction. 
6.2 Changes that Indicate Reproductive 
Capability
Adolescence is marked not only by observable changes but also 
by internal changes that are not visible from the outside. One such 
change is the maturation of various parts involved in the process 
of reproduction.
Both boys and girls experience such changes gradually, and 
these changes are a natural part of the process of growing up. 
An important internal change associated with adolescent girls is 
the onset of the menstrual cycle. It recurs generally every 28–30 
days and is more commonly known as ‘the period’. Many healthy 
girls may have longer or shorter menstrual cycles ranging from 
21–35 days. The menstrual cycle is an important natural process 
and is one of the signs of good reproductive health. The phase of 
the cycle when blood discharge occurs from the body is referred 
to as menstruation. It may last for three to seven days. Some girls 
may feel pain or discomfort in the lower abdomen during these 
days. Usually, by the age of 45–55, menstruation stops naturally, 
marking the end of the reproductive capability in a woman’s life.
Breaking myths about menstruation
There are many wrong beliefs about menstruation that 
often lead to unnecessary fear, shame, or even guilt. These 
beliefs have given rise to certain myths and taboos. Among 
such myths and taboos, physical isolation of menstruating 
girls is unfortunately still quite prevalent. Menstruation is a 
natural process, and such myths have no scientific basis. By 
encouraging a scientific outlook towards menstruation, we can 
help society appreciate the need to promote good reproductive 
health of women and contribute positively towards a healthier 
lifestyle for women.
Chapter 6.indd   77 Chapter 6.indd   77 04-04-2025   04:25:33 04-04-2025   04:25:33