CBSE Class 8 Science Reaching the Age of Adolescence Chapter Notes

Scroll down for PDF

CBSE Class 8 Science Reaching the Age of Adolescence Chapter Notes. Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations.


• The period of life, when the our body undergoes changes, leading to reproductive maturity, is called adolescence.
                     O R
• The period of transition from childhood to adulthood is called adolescence.
• Adolescence begins around the age of 11 and lasts upto 18 to 19 years of age.
• This period covers the 'teens' (13 to 18 or 19 years of age), adolescents are also called 'teenagers.'

The start of the time when a boy is biologically ready to become a father, and a girl is biologically ready to become a mother.

1. What is adolescence ?
2. Define puberty.
3. Adolescents are generally called teenagers. Why ?

Increase in Height :
• The most conspicuous change during puberty is the sudden increase in height. At this time the long bones, that is, the bones of the arms and the legs elongate and make a person tall.
• The rate of growth in height varies in different individuals.
• Height of an individual is more or less similar to that of some family member. This is because height depends on the genes inherited from parents. It is , however, very important to eat the right kind of food during these growing years. This helps the bones, muscles and other parts of the body get adequate nourishment for growth.

Change in Body Shape :
• In boys shoulders generally broaden as a result of growth.
• In girls, the region below the waist becomes wider.
• In boys, the muscles of the body grow more prominently than in the girls.


Voice Change :
• At puberty, the voice box or the larynx begins to grow. Boys develop larger voice boxes. The growing voice boxes in boys can be seen as a protruding part of the throat called Adam's apple.
• In girls, the larynx is hardly visible from the outside because of its small size.
• Generally, girls have a high pitched voice, whereas boys have a deep voice.
Increased Activity of Sweat and Sebaceous Gland :
• During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases. Many young people get acne and pimples on the face at this time because of the increased activity of these glands in the skin.

Development of Sex Organs :
• At puberty, male sex organs like the testes and penis develop completely. The testes also begin to produce sperms.
• In girls, the ovaries enlarge and eggs begin to mature. Also ovaries start releasing mature eggs.
Reaching Mental, Intellectual and Emotional Maturity :

Mental growth :- Thinking skill develops. They are able to think in a more flexible, abstract, and logical way. The ability to see others point of view, exploring ideas, developing concepts and memory skills improve.

Emotional growth :- Emotional changes cause the young person to look at friend and family in new ways. They are very happy at one moment and the very next their mood changes. These comes a feeling of giving and of helping people. Interest in the opposite sex and desire for closeness arise.

Social growth :- In includes developing a personal identity, accepting oneself, forming more mature relationships with peers of both sexes, developing independence and preparing for a career.

1. Name the male sex hormone.
2. List the changes which are occur at puberty.
3. What is Adam's apple ?
4. Name the female sex hormone.

The reproductive organs are testes and ovaries which produce the gametes, i.e., sperms in males and ova in females. The features which help to distinguish the male from the female, are called secondary sexual characters.

Pubertal Changes (Secondary Sexual Characters) in Male :
Widening of shoulders.
Deepening of voice.
Growth of hairs under chest armpits and around pubic area.
Appearance of beard and moustaches.
Growth of sex organs, [Testes & Penis].
Increased activity of sweat and sebaceous glands.
Oily skin and appearance of pimples.
Darkening in skin colour of the genital area.

Pubertal Changes (Secondary Sexual Characters) in Female :
Widening of pelvis and hips.
High pitch voice.
Growth of hairs under armpits and around pubic area.
Initiation of menstrual cycle.
Growth of mammary glands (breasts).
Maturation of secondary sex organs like fallopian tubes, uterus.
Increased activity of sweat and sebaceous glands.
Oily skin and appearance of pimples.
Darkening in skin colour of the genital area.

Please click the link below to download pdf file for CBSE Class 8 Science Reaching the Age of Adolescence Chapter Notes.

Click on the text For more study material for Science please click here - Science

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

CBSE to launch 'Tamanna' aptitude test

Introduction: The poor decisive condition of students to pursue their subject of interest has been an area of concern. To the ease of which CBSE is to launch ‘Tamanna’. An aptitude test in order to provide a line of guidance to students of class 9th and 10th. What is '...

CBSE and Microsoft join hands to build capacity for AI learning for schools

Central Board of Secondary Education and Microsoft join hands to build capacity for AI learning for schools : The officials from the Central Board of Secondary Education have announced that they have partnered with Microsoft India to conduct several capacity building...

TIPS: Study habits for success

Being a student is fairly a difficult job. Alongside maintaining your curricular as well as extra-curricular activities adds more to it. Performance in academics is one of the major concerns. Every parent now tries to get their children more indulged in studies. Need...

CBSE will have more practicals

CBSE board has made a bigger announcement regarding 2020 board examinations for class 12. Board has decided that subjects like humanities, History, English and Hindi will also have practical exams like Chemistry, Biology, and Physics. As per, CBSE official's statement...

Registration of NEET 2020 starts

The NEET 2020 registration process would start on Monday, December 2nd, 2019. National Testing Agency, NTA would carry out the county’s undergraduate entrance exam for medical and dental admissions.  The examination is scheduled to take place in English, Hindi, and...

Guidelines On Reducing Weight Of School Bags

GUIDELINES ON REDUCING WEIGHT OF SCHOOL BAGS In this competitive world, where students are giving their best, an unnoticed threat rides on our back. Heavy School Bags are a serious yet unresolved threat to the health and wellbeing of the young ones. The medium of their...

Studies Today