The stage in which the body undergoes changes to develop into an adult capable of reproduction

What causes acne (pimples) during adolescence?

An increase in oily secretions from the skin that can clog pores and lead to infections

What is the menstrual cycle?

A cycle that recurs generally every 28-30 days involving discharge of blood

What is substance abuse?

Developing a strong urge to regularly consume addictive harmful substances like tobacco alcohol or drugs

What is cyberbullying?

Using digital devices to harass others by sending misleading messages spreading false rumours or sharing personal information without consent

Why is a nutritious diet especially important during adolescence?

Because adolescence is a period of rapid growth and development requiring proteins carbohydrates fats vitamins and minerals for proper body development

Why do myths and taboos about menstruation have no scientific basis?

Menstruation is a natural biological process essential for reproductive health — taboos and myths arose from cultural misunderstanding not scientific evidence — a scientific outlook promotes respect for women's health

Menstruation is unrelated to health

Myths help girls understand their body

How does personal hygiene particularly relate to changes during adolescence?

Hygiene is unrelated to adolescence

Adolescence involves increased body hair growth and increased skin secretions — maintaining hygiene especially in armpits and pubic region prevents infections — menstrual hygiene specifically protects girls from health complications

Only diet affects health during adolescence

Hygiene only matters for adults

Why are addictive substances especially dangerous for adolescents?

Adolescence is marked by curiosity and excitement making adolescents more susceptible to peer pressure — addictive substances cause physical and mental harm and create dependency that can affect the entire future life

Addictive substances are not actually harmful

Adults are more affected by addiction

What is the significance of the Rashtriya Kishor Swasthya Karyakram (RKSK)?

It aims to improve overall health of adolescents including menstrual health using peer education where older students help younger ones learn about these topics

Why do variations in timing of physical changes during adolescence (height voice hair growth) exist between different individuals?

Adolescence is governed by hormones whose production and release timing vary naturally between individuals — these individual differences are a normal expression of human biological diversity

Everyone changes at the same time

How does understanding the science behind adolescent changes help an individual navigate this period more positively?

Scientific understanding replaces fear and confusion with knowledge — knowing that changes are hormone-driven natural biological processes reduces anxiety builds confidence and enables informed decision-making about health and behaviour

How does the chapter connect emotional and behavioural changes during adolescence to making responsible choices?

Adolescence brings stronger emotions that can influence behaviour — understanding how emotions affect actions helps adolescents respond thoughtfully rather than impulsively — this emotional intelligence is the foundation of responsible social media use peer interaction and substance avoidance

Emotions only affect physical health

Behaviour is unrelated to emotions

Analyse why adolescent girls specifically face iron deficiency risks and how this connects to the biology of menstruation.

Iron deficiency is unrelated to menstruation

Monthly menstrual blood loss depletes iron from the body — combined with the high nutritional demands of adolescent growth this makes girls specifically vulnerable to iron deficiency anaemia — demonstrating that biological processes have direct nutritional consequences

All adolescents face equal iron deficiency

Iron deficiency only affects adults

Why is 'saying NO the first time' to addictive substances specifically important in adolescence?

Adolescents have better immunity

Addictive substances create physical and psychological dependency — adolescent brains are still developing making them more vulnerable to addiction — the first exposure can initiate the cycle of dependency — prevention at the first encounter is more effective than treating established addiction

Adolescents recover quickly from addiction

What does the relationship between hormones and adolescent changes reveal about how the body operates as an integrated system?

Hormones are chemical messengers that travel through the bloodstream to coordinate multiple body systems simultaneously — a single hormonal change during adolescence triggers changes in height body structure voice skin and reproduction — demonstrating that the body's systems are deeply interconnected through chemical signalling

Each body part changes independently

How does the chapter's approach to menstruation — treating it as a scientific process worthy of hygiene education and government policy — represent a paradigm shift from historical attitudes?

Menstruation was always treated scientifically

Historically menstruation was surrounded by taboo silence and stigma — treating it as a scientific health issue that deserves government schemes school programmes and open education represents a shift from culturally imposed shame to evidence-based public health — demonstrating that science education can transform social attitudes

Government schemes are not scientific

Only doctors should discuss menstruation

Why is the inclusion of cyberbullying awareness in a science chapter about adolescence significant?

Science and technology are unrelated

Adolescence is a period of heightened emotional sensitivity and social bonding — technology-mediated communication amplifies both positive connection and harm — educating adolescents about cyberbullying within the science curriculum recognises that technological literacy and emotional well-being are inseparable aspects of modern adolescent development

Cyberbullying is not a science topic

Social media only has positive effects

NCERT Solutions Class 7 Science Chapter 6 – Adolescence: A Stage of Growth and Change

Name: Adolescence: A Stage of Growth and Change – Class 7 Science
Uploaded: 2026-07-23T04:33:14+00:00
Description: Adolescence is the transition from childhood to adulthood, usually between 10–19 years, marked by physical, emotional, and behavioural changes. Puberty brings secondary sexual characteristics and reproductive maturity. Healthy habits, hygiene, nutrition, physical activity, and avoiding harmful substances help adolescents grow well.

Class 7 Science

Last Updated: 23 July 2026

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Chapter Introduction

Adolescence is the transition from childhood to adulthood, usually between 10–19 years, marked by physical, emotional, and behavioural changes. Puberty brings secondary sexual characteristics and reproductive maturity. Healthy habits, hygiene, nutrition, physical activity, and avoiding harmful substances help adolescents grow well.

हिंदी में (Hindi)

किशोरावस्था बचपन से वयस्कता की ओर संक्रमण का समय है, जो आमतौर पर 10–19 वर्ष की आयु में होता है, और इसमें शारीरिक, भावनात्मक और व्यवहारिक बदलाव आते हैं। यौवन में द्वितीयक लिंग विशेषताएँ और प्रजनन क्षमता विकसित होती है। स्वस्थ आदतें, स्वच्छता, पोषण, व्यायाम और हानिकारक पदार्थों से दूर रहना किशोरों के सही विकास में मदद करता है।

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Practice MCQ Questions (25 questions)

Q1. What age range does adolescence typically cover?

Q2. What is puberty?

Q3. What are secondary sexual characteristics?

Q4. What causes the change in voice in adolescent boys?

Q5. What is the bump visible in the throat region of adolescent boys called?

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Tough Words (Glossary)

combustion

Meaning: A chemical reaction where a substance burns in oxygen releasing heat and/or light

अर्थ: दहन; ऑक्सीजन में जलने की रासायनिक क्रिया जिसमें ऊष्मा/प्रकाश निकलता है

"Combustion of magnesium produces a white ash."

ignition temperature

Meaning: The lowest temperature at which a substance catches fire

अर्थ: ज्वलनांक; वह न्यूनतम तापमान जिस पर पदार्थ आग पकड़ता है

"Paper burns when it reaches its ignition temperature."

chemical change

Meaning: A change that forms one or more new substances

अर्थ: रासायनिक परिवर्तन; जिसमें नए पदार्थ बनते हैं

"Rusting is a chemical change."

physical change

Meaning: A change in shape, size, or state with no new substance formed

अर्थ: भौतिक परिवर्तन; आकार/आवस्था बदलती पर नया पदार्थ नहीं बनता

"Melting ice is a physical change."

bioluminescence

Meaning: Light produced by a living organism due to a chemical reaction

अर्थ: जैव-दीप्ति; जीवों द्वारा रासायनिक क्रिया से उत्पन्न प्रकाश

"Fireflies glow due to bioluminescence."

extinguish

Meaning: To put out a fire or flame

अर्थ: बुझाना; आग को समाप्त करना

"Covering the candle with a glass extinguished the flame."

lime water

Meaning: A solution of calcium hydroxide in water

अर्थ: चूने का पानी; कैल्शियम हाइड्रॉक्साइड का विलयन

"Blowing into lime water makes it milky."

calcium carbonate

Meaning: A white insoluble solid formed in some reactions

अर्थ: कैल्शियम कार्बोनेट; एक सफेद अविलेय ठोस

"Calcium carbonate forms when CO₂ reacts with lime water."

insoluble

Meaning: Not able to dissolve in a liquid

अर्थ: अविलेय; जो द्रव में नहीं घुलता

"Chalk is insoluble in water."

precipitate

Meaning: A solid that forms and settles from a liquid during a reaction

अर्थ: अवक्षेप; विलयन से बनने वाला ठोस

"A white precipitate appeared in the test tube."

erosion

Meaning: Wearing away and movement of soil or rock by wind or water

अर्थ: कटाव; हवा/पानी द्वारा मिट्टी या चट्टान का बह जाना

"River water causes erosion of the banks."

weathering

Meaning: Breaking down of rocks by physical and chemical processes

अर्थ: अपक्षय; भौतिक व रासायनिक प्रक्रियाओं से चट्टानों का टूटना

"Weathering turns big rocks into soil over time."

sediment

Meaning: Material that settles at the bottom of water

अर्थ: अवसाद; पानी के तल में जमा पदार्थ

"Fine sediment collected at the lake bed."

basalt

Meaning: A dark volcanic rock

अर्थ: बेसाल्ट; एक गहरा ज्वालामुखीय पत्थर

"Basalt turned reddish due to oxidation."

oxidation

Meaning: A chemical reaction where a substance combines with oxygen

अर्थ: ऑक्सीकरण; ऑक्सीजन के साथ संयोजन की क्रिया

"Iron undergoes oxidation to form rust."

rusting

Meaning: Formation of brown iron oxide on iron in moist air

अर्थ: जंग लगना; आर्द्र वायु में लोहे पर भूरी परत बनना

"Keeping iron wet speeds up rusting."

vapourisation

Meaning: Change of a liquid into vapour (gas)

अर्थ: वाष्पीकरण; द्रव का वाष्प में बदलना

"Vapourisation of water forms steam."

condensation

Meaning: Change of gas into liquid on cooling

अर्थ: संघनन; गैस का ठंडा होकर द्रव बनना

"Condensation formed drops on the bottle."

solidification

Meaning: Change of liquid into solid on cooling

अर्थ: ठोसकरण; द्रव का ठंडा होकर ठोस बनना

"Solidification turns melted wax solid again."

evaporation

Meaning: Slow change of liquid to vapour at the surface

अर्थ: वाष्पन; सतह से द्रव का धीरे-धीरे वाष्प में बदलना

"Evaporation dries wet clothes."

state (of matter)

Meaning: Form in which matter exists: solid, liquid, or gas

अर्थ: अवस्था; ठोस/द्रव/वायु रूप

"Water exists in all three states."

reaction

Meaning: A process where substances change into new substances

अर्थ: अभिक्रिया; पदार्थों का नए पदार्थों में बदलना

"The reaction produced bubbles."

fume hood

Meaning: A ventilated enclosure for safely handling gases/vapours

अर्थ: धूम-हुड; वाष्प/गैस से सुरक्षित कार्य हेतु वायु-संचालित कक्ष

"Burn sulfur only under a fume hood."

deflagrating spoon

Meaning: A long-handled metal spoon for burning substances safely

अर्थ: दहन-चम्मच; सुरक्षित जलाने हेतु लंबा धातु चम्मच

"Sulfur was burnt in a deflagrating spoon."

tumbler

Meaning: A glass or cup without a handle

अर्थ: गिलास; बिना हैंडल वाला पात्र

"Add lime water to the tumbler."

petri dish

Meaning: A shallow dish used in experiments

अर्थ: पेट्री डिश; प्रयोगों में प्रयुक्त उथला पात्र

"Place the candle on a petri dish."

wick

Meaning: The string in a candle that draws up melted wax

अर्थ: बाती; मोमबत्ती में मोम ऊपर खींचने वाली डोरी

"The wick soaked up the melted wax."

fizzing

Meaning: A hissing sound due to gas bubbles forming

अर्थ: फुफकार/झाग की आवाज; गैस बनने से आने वाली ध्वनि

"Mixing soda and vinegar caused fizzing."

bubbling

Meaning: Formation of bubbles in a liquid

अर्थ: बुलबुलाना; द्रव में बुलबुले बनना

"Bubbling showed a gas was produced."

exhale

Meaning: To breathe out

अर्थ: श्वास छोड़ना; साँस बाहर निकालना

"We exhale carbon dioxide."

milky

Meaning: Cloudy white in appearance

अर्थ: दूधिया; धुंधला सफेद

"Lime water turned milky."

combustible

Meaning: Able to catch fire and burn

अर्थ: ज्वलनशील; जो आसानी से जल सके

"Paper is a combustible substance."

fuel

Meaning: A substance burned to produce heat or energy

अर्थ: ईंधन; ऊष्मा/ऊर्जा देने हेतु जलाया जाने वाला पदार्थ

"Wood is used as a fuel in villages."

oxygen

Meaning: A gas in air essential for burning and breathing

अर्थ: ऑक्सीजन; जलने व श्वास के लिए आवश्यक गैस

"Oxygen supports combustion."

carbon dioxide

Meaning: A gas exhaled by us and formed in many reactions

अर्थ: कार्बन डाइऑक्साइड; हमारे द्वारा छोड़ी जाने वाली गैस

"Carbon dioxide turned lime water milky."

vinegar

Meaning: A sour liquid containing acetic acid

अर्थ: सिरका; एसीटिक अम्ल वाला खट्टा तरल

"Vinegar reacts with baking soda."

baking soda

Meaning: Sodium hydrogen carbonate, a basic salt

अर्थ: बेकिंग सोडा; सोडियम हाइड्रोजन कार्बोनेट, क्षारीय लवण

"Baking soda produced bubbles with vinegar."

reversible

Meaning: Able to be changed back to the original form

अर्थ: उलटनीय; जिसे वापस पूर्व रूप में लाया जा सके

"Melting of ice is reversible."

irreversible

Meaning: Not able to return to the original form

अर्थ: अनुलटनीय/अपरिवर्तनीय; जिसे वापस न किया जा सके

"Making popcorn is irreversible."

decomposition

Meaning: Breaking down of a substance into simpler parts

अर्थ: अपघटन; पदार्थ का सरल भागों में टूटना

"Food decomposition makes compost."

desirable

Meaning: Good or useful to have

अर्थ: वांछनीय; लाभकारी

"Curd formation is a desirable change."

undesirable

Meaning: Not wanted or harmful

अर्थ: अवांछनीय; हानिकारक

"Food spoilage is undesirable."

settle

Meaning: To sink and rest at the bottom

अर्थ: बैठना/जमना; तल में जमा होना

"The white solid settled at the bottom."

dissolve

Meaning: To mix uniformly in a liquid

अर्थ: घुलना; द्रव में समान रूप से मिलना

"Sugar dissolves in water."

formation

Meaning: The act of creating or coming into being

अर्थ: निर्माण; बनना

"The formation of rust takes time."

evaporate

Meaning: To change from liquid to gas

अर्थ: उड़ना/वाष्पित होना; द्रव से गैस बनना

"Water will evaporate in the sun."

condense

Meaning: To change from gas to liquid

अर्थ: संघनित होना; गैस से द्रव बनना

"Steam condenses on a cool surface."

ignite

Meaning: To start burning

अर्थ: प्रज्वलित करना; आग लगना

"The match ignited the paper."

magnifying glass

Meaning: A lens that makes objects appear bigger

अर्थ: आवर्धक काँच; वस्तुओं को बड़ा दिखाने वाला लेंस

"Use a magnifying glass to focus sunlight."

heat

Meaning: Energy that makes things warm or hot

अर्थ: ऊष्मा; गर्मी देने वाली ऊर्जा

"Heat speeds up many changes."

light

Meaning: Visible form of energy that helps us see

अर्थ: प्रकाश; देखने में सहायक ऊर्जा

"The reaction released heat and light."

moist

Meaning: Slightly wet

अर्थ: नम; थोड़ा गीला

"Rust forms faster in moist air."

dazzling

Meaning: Extremely bright

अर्थ: चमचमाता/चकाचौंध करने वाला

"Magnesium burns with a dazzling flame."

cloudy

Meaning: Not clear; full of tiny particles

अर्थ: धुंधला; अस्पष्ट

"The solution turned cloudy."

expand

Meaning: To increase in size or volume

अर्थ: फैलना/विस्तृत होना

"Metals expand on heating."

contract

Meaning: To decrease in size

अर्थ: सिकुड़ना

"Wax contracts when it cools."

suspend

Meaning: To keep particles floating in a liquid

अर्थ: स्थगित/झूलते रहना; द्रव में कणों का तैरना

"Soot particles were suspended in air."

odor

Meaning: A smell

अर्थ: गंध/सुगंध

"The fruit had a strong odor."

settling time

Meaning: Time taken for particles to deposit

अर्थ: अवसादन समय; कणों के तल पर बैठने का समय

"The settling time of the solid was short."

flammable

Meaning: Easily set on fire

अर्थ: ज्वलनशील; आसानी से जलने वाला

"Kerosene is highly flammable."

reaction equation

Meaning: A short way to show a chemical change using symbols

अर्थ: अभिक्रिया समीकरण; प्रतीकों से रासायनिक परिवर्तन का संक्षिप्त रूप

"Write the reaction equation for rusting."

vapour

Meaning: Gas form of a substance normally liquid or solid

अर्थ: वाष्प; सामान्यतः द्रव/ठोस का गैसीय रूप

"The wax turned into vapour near the flame."

residue

Meaning: A small amount of substance left behind

अर्थ: अवशेष; बचा हुआ पदार्थ

"A black residue remained after burning."

climatic

Meaning: Related to climate

अर्थ: जलवायवीय; जलवायु से संबंधित

"Climatic changes affect weathering."

sedimentary rock

Meaning: Rock formed from compacted sediments

अर्थ: अवसादी शैल; अवसादों से बनी चट्टान

"Sand layers later form sedimentary rock."

myth

Meaning: a widely held but false belief

अर्थ: मिथक

"It is a myth that menstruation makes girls weak."

taboo

Meaning: a social or cultural restriction

अर्थ: वर्जना

"Talking about periods was once a taboo."

isolation

Meaning: the state of being separated

अर्थ: अलगाव

"Isolation of girls during periods is wrong."

emotion

Meaning: a strong feeling like joy, anger, or fear

अर्थ: भावना

"Adolescents experience strong emotions."

behaviour

Meaning: the way a person acts

अर्थ: व्यवहार

"Good behaviour makes friends easily."

curiosity

Meaning: a strong desire to know or learn

अर्थ: जिज्ञासा

"Curiosity led him to ask many questions."

nutrition

Meaning: food needed for growth and health

अर्थ: पोषण

"Good nutrition is important in adolescence."

hygiene

Meaning: conditions or practices for cleanliness and health

अर्थ: स्वच्छता

"Personal hygiene keeps us safe from disease."

sanitary pad

Meaning: an absorbent item used during menstruation

अर्थ: सैनेटरी पैड

"Sanitary pads should be changed regularly."

initiative

Meaning: a new plan or action to solve a problem

अर्थ: पहल

"The government started an initiative on hygiene."

biodegradable

Meaning: able to decay naturally and not harm the environment

अर्थ: जैव-अपघटनीय

"Biodegradable pads are eco-friendly."

fitness

Meaning: the state of being healthy and strong

अर्थ: तंदुरुस्ती

"Daily exercise improves fitness."

stamina

Meaning: the ability to sustain effort for a long time

अर्थ: सहनशक्ति

"Running increases stamina."

interaction

Meaning: communication or direct involvement with someone

अर्थ: परस्पर क्रिया

"Healthy interaction builds trust."

social media

Meaning: online platforms for sharing and communication

अर्थ: सामाजिक मीडिया

"Teenagers spend time on social media."

cyberbullying

Meaning: using technology to harass someone online

अर्थ: ऑनलाइन धमकाना

"Cyberbullying can harm mental health."

rumour

Meaning: a piece of information that may not be true

अर्थ: अफ़वाह

"He spread a rumour about his classmate."

addiction

Meaning: a strong and harmful need to regularly have something

अर्थ: लत

"Addiction to smoking is dangerous."

substance abuse

Meaning: the harmful use of drugs or alcohol

अर्थ: नशीली वस्तुओं का दुरुपयोग

"Substance abuse affects the brain badly."

counselling

Meaning: professional advice and guidance

अर्थ: परामर्श

"He went for counselling to overcome stress."

helpline

Meaning: a phone service offering help and advice

अर्थ: सहायता फ़ोन सेवा

"Call the helpline in case of emergency."

hormone

Meaning: a chemical substance in the body that controls growth and development

अर्थ: हार्मोन

"Hormones cause many changes in adolescence."

regulate

Meaning: to control or manage

अर्थ: नियंत्रित करना

"Hormones regulate body functions."

signal

Meaning: a sign or action that sends a message

अर्थ: संकेत

"The red light is a signal to stop."

foundation

Meaning: the base or beginning of something

अर्थ: आधार

"Education is the foundation of success."

responsibility

Meaning: a duty to take care of something

अर्थ: जिम्मेदारी

"Adolescents should learn responsibility."

confidence

Meaning: belief in oneself

अर्थ: आत्मविश्वास

"Confidence helps in public speaking."

guidance

Meaning: help or advice given to someone

अर्थ: मार्गदर्शन

"Teachers provide guidance to students."

awareness

Meaning: knowledge or understanding of something

अर्थ: जागरूकता

"Awareness about health is important."