Science · Class 7 · Chapter 6

Adolescence: A Stage of Growth and Change

Aim: Build a clear, working understanding of this chapter's key ideas, connected to real NCERT examples, worked problems, and everyday situations.
  • Adolescence — The stage between childhood and adulthood, ~10–19 years.
  • Puberty — When the body becomes capable of reproduction.
  • Secondary sexual characteristics — Features like voice change, facial hair, breast development.
  • Acne — Pimples from increased oily skin secretions.
  • Menstruation — The bleeding phase of the menstrual cycle.
  • Menstrual cycle — The recurring reproductive cycle, ~28–30 days.
  • Hormones — Body chemicals regulating growth, mood, and behaviour.
  • Substance abuse — Repeated, addictive use of harmful substances.
40 min lesson

Chapter 6 · Concept 1 of 12

The Stages of Life

  • Adolescence (10–19 yrs)

Chapter 6 · Concept 2 of 12

Visible Physical Changes

  • Height and build — A noticeable increase in height. Boys often develop broader shoulders and chest; girls develop breasts and other body changes.
  • Weight — A gradual increase in body weight is a normal part of this stage of growth.

Chapter 6 · Concept 3 of 12

Voice Changes and Hair Growth

  • Voice — The voice box (larynx) grows, giving boys a hoarser voice — sometimes visible as the Adam's apple. Girls' voice boxes grow too, though less noticeably.
  • Hair growth — New hair growth appears in the armpits and pubic region in both sexes. Boys often develop facial hair — timing and extent vary normally between individuals.

Chapter 6 · Concept 4 of 12

Acne and Secondary Sexual Characteristics

  • Acne — Increased oily skin secretions during adolescence can clog pores, causing reddish pimples.
  • Secondary sexual characteristics — Features like voice change, facial hair, and breast development mark the onset of puberty — the stage where the body becomes capable of reproduction.

Chapter 6 · Concept 5 of 12

The Menstrual Cycle

  • The cycle — Typically recurs every 28–30 days, with a normal healthy range of 21–35 days.
  • Menstruation — The bleeding phase, usually lasting 3–7 days. It begins at puberty and stops naturally around ages 45–55.

Chapter 6 · Concept 6 of 12

There Is No Scientific Basis for Taboos

  • Some communities isolate menstruating girls due to long-standing myths and taboos.
  • What science tells us — These practices have no scientific basis. Menstruation is a normal, healthy part of the reproductive cycle, and a scientific outlook should be encouraged.

Chapter 6 · Concept 7 of 12

Emotional and Behavioural Changes

  • Stronger emotions — Adolescence often brings mood swings and heightened sensitivity, compared to childhood.
  • Channelled well — These same emotional changes can lead to creativity, compassion, and greater social involvement.

Chapter 6 · Concept 8 of 12

Nutrition During Adolescence

  • Adolescents need proteins, carbohydrates, fats, vitamins, and minerals for proper growth.
  • Calcium — For strong, healthy bones.
  • Iron — For healthy blood formation.

Chapter 6 · Concept 9 of 12

Hygiene, and Support from the Government

  • Menstrual hygiene is maintained with sanitary pads or reusable cloth pads; used pads should be wrapped and disposed of in a dustbin.
  • Scheme | What it does
  • Menstrual Hygiene Scheme (MHS) — Free or low-cost pads for rural adolescent girls
  • Rashtriya Kishor Swasthya Karyakram (RKSK) — Overall adolescent health, through peer education
  • Suvidha Sanitary Napkin Initiative — Biodegradable pads via Jan Aushadhi Kendras

Chapter 6 · Concept 10 of 12

Physical Activity and a Balanced Social Life

  • Physical activity — Regular activity keeps the body and mind fit, and helps boost mood.
  • Cyberbullying — Harassment through digital platforms — misleading messages, false rumours, or sharing private information without consent. Report it to parents or teachers, don't hide it.

Chapter 6 · Concept 11 of 12

Avoiding Harmful Substances

  • Substance abuse — Repeated, addictive use of tobacco, alcohol, or drugs can cause breathing difficulties, memory loss, and lung damage.
  • Getting help — The Nasha Mukt Bharat Abhiyaan spreads awareness against substance abuse. The National De-addiction Helpline (14446) offers confidential support.

Chapter 6 · Concept 12 of 12

Hormones: The 'Why' Behind Adolescence

  • Nearly every change in this chapter — physical, reproductive, and emotional — traces back to one cause.
  • Hormones — Chemicals produced in the body, released in response to brain signals, that regulate growth, development, mood, and behaviour.

Quick Recap

Check Your Understanding

  1. 1Ramesh, 11, developed pimples and his mother said it's from ongoing biological changes. (i) What could cause this? (ii) What can he do for relief?
  2. 2Which food group is a better choice for adolescents, and why?
  3. 3Unscramble the underlined word in each sentence: (i) nstmnoiaretu — blood discharge every 28–30 days. (ii) iceov xob — enlarged, causing hoarser voice. (iii) urtypeb — the body preparing for adulthood. (iv) lahoclo and srugd — say NO, as they're addictive.