L
LLLOS.ai
Learn
L
Class 8 Physical Education (Khel Yatra)

Unit 1 — Foundations of Physical Education and Well-being

Start learning → Step-by-step lesson with a teacher voice, questions and notes.

Reading view

Overview

This unit shows that a physical education period is far more than a game. Each activity is used to teach an idea from science or from life, and you feel that idea in your own body. You begin with the shape of every session in this book: warm-up, the main activity, cool-down and circle time, and the safety habits that go with them. Through a vaulting race you learn about balance and the centre of gravity. A mass drill on a count of eight introduces the major muscles of the arms and legs. Two chasing games, Baraf Pani and Char Tali, are used to understand bullying and harassment: who the bully, the target, the bystander and the upstander are, how society can protect a victim, and how to report a problem to a trusted adult. Relays then bring physics onto the field: heat moving by conduction, and linear, rotational and projectile motion measured in SI and CGS units. Biology follows: how breathing and pulse rise with effort and fall during recovery, how the brain and muscles work together (neuromuscular control), how bones, joints and muscles act like a machine, and how the body adapts to strength, endurance and flexibility training when it also gets rest. The unit closes with honest self-assessment, so that you can track your own progress and keep improving.

हिंदी में पढ़ें

इस इकाई में हर खेल कोई न कोई विचार सिखाता है। घोड़ा कूद दौड़ दिखाती है कि संतुलन और गुरुत्व केंद्र कैसे काम करते हैं। सामूहिक ड्रिल से आप उन मांसपेशियों के नाम जानते हैं जिनका आप उपयोग करते हैं। बरफ़ पानी और चार ताली जैसे दो भारतीय दौड़-पकड़ खेल धमकाने और उत्पीड़न को समझने तथा अपस्टैंडर बनकर कदम उठाने में मदद करते हैं। रिले दौड़ें विज्ञान को मैदान पर ले आती हैं: चालन द्वारा ऊष्मा का स्थानांतरण, SI और CGS इकाइयों में मापी गई तीन प्रकार की गति, और मेहनत के साथ बढ़ती श्वास और नाड़ी। आप यह भी सीखते हैं कि तंत्रिकाएँ, मांसपेशियाँ, हड्डियाँ और जोड़ मिलकर कैसे काम करते हैं और प्रशिक्षण व विश्राम से शरीर कैसे मज़बूत होता है। हर सत्र वार्म-अप, गतिविधि, कूल-डाउन और सर्कल टाइम के क्रम में चलता है, ताकि आप सुरक्षित रहें और हर खेल से सीखें।

Learning Objectives

  • Describe the four parts of every session (warm-up, activity, cool-down, circle time) and follow basic safety rules on the field.
  • Explain balance and the centre of gravity and use them to vault safely over a partner.
  • Name the major muscles of the arms and legs and perform a drill in rhythm on a count of eight.
  • Identify the roles of bully, target, bystander and upstander, and describe safe ways to stop and report bullying and harassment.
  • Explain conduction and the three types of motion, and record measurements in SI and CGS units.
  • Measure resting and exercise pulse and breathing rates and explain why they change with intensity.
  • Explain neuromuscular control and how bones, joints and muscles work together to produce movement.
  • Describe how the musculoskeletal system adapts to strength, endurance and flexibility training, and why rest is part of training.
  • Assess your own skills and attitudes honestly and set a goal for improvement.

Topics in this chapter

12 topics · tap a topic title to jump straight to it.

Topic 1 of 12
⚙️1

How a PE session works: warm-up, activity, cool-down and circle time

By the end you canPlan and follow a safe PE session with a proper warm-up, activity, cool-down and circle time.

1Think first

Why do athletes at a big match spend so long jogging and stretching before the game starts?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Every activity in this unit follows the same four-part plan. Learning the plan is the first skill, because it is what keeps you safe and makes each period useful.

  • Warm-up (about 8-10 minutes). Light jogging, skipping, arm circles and dynamic stretches such as walking lunges. The warm-up slowly raises your heart rate, sends more blood to the muscles, makes muscles and joints more supple and gets the mind ready. Cold muscles tear more easily, so never jump straight into sprinting or jumping.
  • Main activity. The game, relay or drill that teaches the idea of the day.
  • Cool-down (about 5 minutes). Slow jogging that becomes walking, then static stretches held for 15-30 seconds, and deep breathing. This brings the heart rate down gradually and reduces stiffness the next day.
  • Circle time. The class sits in a circle and talks about what happened: which technique worked, how a role felt, what science was at work. This is where play turns into learning.

Dynamic and static stretching are different. Dynamic stretches are moving ones (leg swings, arm rotations) and suit the warm-up. Static stretches are held still and suit the cool-down.

Safety habits for every period:

  • Wear comfortable clothes and proper sports shoes with laces tied; remove watches, sharp hair clips and chains.
  • Check the ground for stones, glass, wet patches or holes before you play.
  • Drink water before and after activity, especially in Indian summers. Play in shade or in the cooler part of the day when it is very hot.
  • Keep an arm's distance from others in drills and follow the teacher's whistle at once.
  • Stop and tell the teacher if you feel dizziness, chest pain, unusual breathlessness or sharp pain. Pain is a signal, not a challenge.
  • Tell the teacher in advance about asthma, a recent injury or any health condition.

Physical education aims at well-being: a healthy body, a calm and confident mind, good relationships and a sense of joy. So in circle time you will also talk about feelings, fairness and teamwork, not only scores.

Formulas to remember
  1. Session order: warm-up, then main activity, then cool-down, then circle time.
  2. Dynamic stretching belongs in the warm-up; static stretching (held 15-30 seconds) belongs in the cool-down.
  3. Safety rule: stop immediately and inform the teacher on dizziness, chest pain or sharp pain.
Whenmuscles are warmed up graduallyThenthey become more supple and the chance of a strain or tear falls
Whenyou stop hard exercise suddenly without a cool-downThenblood can pool in the legs and you may feel dizzy

3Worked example

Design a 10-minute warm-up for a running game in the school ground.
Step 1Minutes 0-3: easy jogging around the ground to raise the heart rate.
Step 2Minutes 3-5: arm circles forward and backward, shoulder shrugs and trunk twists.
Step 3Minutes 5-8: dynamic leg work such as walking lunges, leg swings and high knees.
Step 4Minutes 8-10: two short runs at half speed, then three-quarter speed.
Step 5Check yourself: you should feel warm and slightly out of breath, but not tired.
More examples
  • Before a relay: 3 minutes of jogging, 2 minutes of arm rotations and leg swings, then 10 high-knee steps and 10 butt-kicks.
  • After a relay: 2 minutes of slow jogging becoming walking, then a quadriceps stretch and a hamstring stretch held for 20 seconds each side.
  • In May in Delhi, a class shifts its PE period to the early morning and keeps water bottles at the edge of the ground.

4Your turn

Which of these belongs in the cool-down rather than the warm-up?

5Remember this

One line to keepWarm up before, cool down after, and talk it through in circle time: that order keeps you safe and turns play into learning.
Common mistake. Doing long static stretches on cold muscles as the whole warm-up. Muscles first need light movement to warm up; long held stretches are for the cool-down.
Topic 2 of 12
🍎2

Balance and centre of gravity: the Horse Vault Race

By the end you canUse the ideas of centre of gravity and base of support to vault and hold positions safely.

1Think first

Why is it easier to push over a friend standing on one leg than one standing with feet wide apart?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Every body has a centre of gravity: the point where its weight can be thought to act. For a person standing straight it lies roughly near the navel, a little inside the body. You stay balanced as long as this point is above your base of support, the area enclosed by the parts touching the ground. Three rules follow, and every sport uses them.

  • A wider base gives more stability. A wrestler stands with feet apart; a person on one foot wobbles.
  • A lower centre of gravity gives more stability. That is why a kabaddi defender crouches.
  • When the centre of gravity moves outside the base, you start to fall, unless you move the base, for example by taking a step.

In the Horse Vault Race, pairs of similar height and weight race to a finish line by taking turns to vault over each other. One partner becomes the ‘horse’: knees and hands on the ground or a firm squat on all fours, back flat, head tucked so the chin points to the chest. The other places both hands on the horse's back, pushes down, and swings the legs apart and over. Then the roles swap, again and again, until the pair crosses the line.

The horse is stable because it has four points of support and a low centre of gravity. The jumper is briefly balanced on the hands, so the push must go straight down through the middle of the horse's back, not to one side, or both of you will topple.

Safety first:

  • Pair up with someone of similar size; never vault over a much smaller partner.
  • The horse keeps the head tucked in and stays still until the jumper has landed.
  • Hands go flat on the upper back, never on the neck or head.
  • Land on both feet with bent knees, then move forward to make space.
  • Play on grass or a soft, level surface. Start slowly; speed comes later.

In circle time, compare techniques. Was a quick, light push better than a slow heavy one? Who kept the best balance as the horse? Sideways vaults can be added once everyone is confident.

Formulas to remember
  1. Balance condition: the body is stable while its centre of gravity stays over its base of support.
  2. Stability increases with a wider base and a lower centre of gravity.
  3. Safety rule: pair by similar height and weight; hands on the upper back, never the neck.
Whenthe base of support is made widerThenthe body becomes more stable
Whenthe centre of gravity moves outside the base of supportThenthe body begins to fall unless a step widens the base

3Worked example

Try a safe first vault with a partner of similar size.
Step 1The horse kneels on all fours on grass, back flat, head tucked, hands under shoulders.
Step 2The jumper stands one step behind, then places both hands flat on the horse's upper back.
Step 3The jumper pushes straight down, opens the legs wide and swings them over the horse's sides.
Step 4Land on both feet with knees bent, then take two steps forward.
Step 5Swap roles. Judge yourself: did the horse move? If yes, your push was off-centre.
More examples
  • A cyclist balancing at a red light puts one foot down to widen the base of support.
  • A goalkeeper in hockey crouches low before a penalty stroke to lower the centre of gravity and react quickly.
  • In the vault race, a jumper who pushes to the left side of the horse's back makes the horse tip over to the left.

4Your turn

Which position is the most stable?

5Remember this

One line to keepStay stable by keeping your centre of gravity low and over a wide base.
Common mistake. Pushing forward on the horse's back instead of straight down. A forward push shoves the horse and both partners can fall.
Topic 3 of 12
💪3

Major muscles and rhythm: the Progressive Mass Drill

By the end you canPerform a drill in time on a count of eight and name the main muscle working in each movement.

1Think first

When you bend your elbow, which muscle is pulling, and what is the muscle on the other side doing?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

A mass drill is a set of exercises performed by the whole class together, in time with a count. In the Progressive Mass Drill, students stand in rows with an arm's distance between them. A demonstrator stands on a raised platform facing the class, the teacher calls the counts from one to eight, and everyone copies each movement exactly on the count. ‘Progressive’ means the drill becomes harder step by step: first free-hand movements, then with objects such as a stick, light dumbbells, a ball, a hoop, a rope or a ribbon, and the beat can come from a drum instead of the voice.

A typical eight-count movement: on 1 raise the arms sideways, on 2 raise them overhead, on 3 lower to the side, on 4 return to the start; counts 5-8 repeat with a step to the right. Moving together needs rhythm (keeping time) and coordination (body parts moving in the right order).

The drill is also a chance to name the major muscles you feel working:

MuscleWhereMain job
DeltoidTop of the shoulderLifts the arm sideways and forwards
BicepsFront of upper armBends the elbow
TricepsBack of upper armStraightens the elbow
QuadricepsFront of thighStraightens the knee
HamstringsBack of thighBends the knee
Gluteus maximusButtocksPushes the hip back; powers climbing and jumping
Calf (gastrocnemius)Back of lower legRaises the heel; pushes off in running

Notice that muscles work in pairs: when the biceps shortens to bend the elbow, the triceps relaxes, and the reverse happens to straighten it. Place a hand on your upper arm while bending and straightening to feel this.

How to do it well and safely: keep the arm's-distance spacing so that sticks and hoops never hit a neighbour, move with control rather than flinging the limbs, keep your back straight, and breathe normally rather than holding your breath. Judge your own performance: were you exactly on the count, and did your movement match the demonstrator's? A class moving perfectly together is a satisfying sight, and that shared rhythm is part of the joy of the drill.

Formulas to remember
  1. Muscles work in opposing pairs: biceps bends the elbow, triceps straightens it; hamstrings bend the knee, quadriceps straighten it.
  2. Drill spacing rule: at least one arm's distance between students, more when holding equipment.
Whenthe biceps contractsThenthe elbow bends and the triceps relaxes
Whenan object such as a stick or dumbbell is addedThenthe same movement needs more muscular force

3Worked example

Lead a partner through one eight-count sequence and name the muscles used.
Step 1Count 1: arms sideways to shoulder level (deltoids).
Step 2Count 2: arms overhead (deltoids, trapezius).
Step 3Count 3: arms down and bend knees into a half squat (quadriceps, gluteus maximus).
Step 4Count 4: stand up straight with arms at the sides.
Step 5Counts 5-8: repeat while stepping to the right on 5 and back on 8.
Step 6Check: did you both arrive at each position on the same count?
More examples
  • Republic Day school parades and mass PT displays on Sports Day use the same count-of-eight system.
  • Holding a lathi (stick) overhead on count 2 makes the deltoids and triceps work harder than free hands.
  • Squatting on count 3 and standing on count 4 works the quadriceps and gluteus maximus.

4Your turn

Which muscle straightens the knee when you stand up from a squat?

5Remember this

One line to keepMoving together on a count builds rhythm and coordination, and every movement is powered by a named muscle pulling against its partner.
Common mistake. Thinking a muscle can push. Muscles can only pull by shortening; that is why they must work in pairs to move a joint both ways.
Topic 4 of 12
🔬4

Bullying and the upstander: Baraf Pani

By the end you canRecognise bullying and the four roles, and choose safe ways to act as an upstander.

1Think first

If you watch someone being teased every day and say nothing, are you part of the problem?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Bullying is hurting or frightening someone on purpose, again and again, when the person finds it hard to defend themselves. It can be physical (pushing, hitting, snatching things), verbal (name-calling, teasing about looks, caste, region, accent or ability), social (leaving someone out, spreading rumours) or cyber (hurtful messages, photos or posts online). A one-time fight between equals is a conflict; bullying is about repeated harm and an imbalance of power.

Four roles appear in almost every bullying situation:

  • Bully: the person doing the harm.
  • Target (victim): the person being harmed.
  • Bystanders: people who see it happen and do nothing.
  • Upstander: a bystander who chooses to act.

The game Baraf Pani (ice and water), a familiar Indian freeze-tag, is adapted to feel these roles. One student is the Bully, one is the Upstander, and the rest run as Bystanders and Victims. When the Bully tags someone, that player freezes (‘baraf’). A Bystander can unfreeze a frozen player (‘pani’) with a tap, but only while saying something reassuring, such as ‘You are not alone’. The Upstander can stop the Bully by tagging them and saying firmly, ‘Stop, that is not okay.’ Roles are rotated so everyone experiences each one.

The game teaches two truths. First, kindness from even one person makes the target feel less alone. Second, the bully loses power when someone stands up. In real life, being an upstander does not mean fighting. Safe ways to act are:

  • Refuse to laugh or join in, and do not forward hurtful messages.
  • Stay with the target and invite them to join your group.
  • Say calmly, ‘Stop, this is not okay,’ only if it is safe to do so.
  • Tell a trusted adult: a teacher, the school counsellor or a parent. Reporting is not ‘complaining’; it is protecting someone.

If you are the target, remember it is not your fault. Speak to an adult you trust; in India, the child helpline 1098 is free. In circle time, share how each role felt. Many students find that being the Upstander felt the strongest of all.

Formulas to remember
  1. Bullying = deliberate, repeated harm + an imbalance of power.
  2. Four roles: bully, target, bystander, upstander.
  3. Safe upstander steps: do not join in, support the target, speak up if safe, report to a trusted adult.
Whenbystanders laugh or stay silentThenthe bully feels approved and the bullying usually continues
Wheneven one person supports the target and reports itThenthe target feels less alone and adults can step in

3Worked example

You see two classmates snatching a younger student's tiffin every day. What do you do?
Step 1Do not cheer or watch as entertainment.
Step 2After the incident, go to the younger student and ask if they are all right.
Step 3Invite them to eat with your group so they are not alone.
Step 4Tell your class teacher or counsellor exactly what you saw, when and where.
Step 5Check later whether things have improved; if not, tell the adult again.
More examples
  • A group keeps mocking a new student's accent; an upstander sits with her at lunch and tells the class teacher.
  • A classmate's photo is edited and shared to mock him; upstanders refuse to forward it and report it.
  • In Baraf Pani, a Bystander unfreezes a Victim with a tap and the words ‘I am with you’.

4Your turn

What makes someone an upstander rather than a bystander?

5Remember this

One line to keepBullying thrives on silence; one upstander who supports the target and tells a trusted adult can stop it.
Common mistake. Believing that telling a teacher is ‘snitching’. Reporting harm to a trusted adult is the responsible, safe thing to do.
Topic 5 of 12
🔬5

Harassment and the role of society: Char Tali

By the end you canRecognise harassment, know how to keep yourself safe, and understand why society must act early to protect a victim.

1Think first

In a crowded bus, if one person is being troubled and twenty people look away, who is responsible?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Harassment is unwanted behaviour that makes a person feel uncomfortable, scared, insulted or unsafe. It can be words, gestures, staring, following, unwanted touching, or messages and photos sent online. A key idea is consent: your body and your personal space belong to you, and no one, whether a stranger or someone you know, has the right to touch you or speak to you in a way that makes you feel unsafe. Children are protected by law in India, and adults have a duty to act when a child reports harm.

Harassment is stopped more effectively when the people around a victim, the society, are alert and act together. The game Char Tali (four claps) is used to feel this. Four lines are marked: a starting line, a warning line, a danger line and a finish line. One team plays the ‘Aggressor’ and the other plays ‘Society’. One member of Society is the victim, who stands at the finish line with their back to the field. The other Society members spread across the warning and danger zones, with fewer in the danger zone.

The Aggressors creep forward while the victim's back is turned. The victim claps four times and then turns around quickly; any Aggressor caught moving is out. Society members try to make Aggressors move, without touching them, so the victim can spot them. If an Aggressor reaches the warning line, Society players in the warning zone are out; reaching the danger line puts out those in the danger zone. Aggressors win by reaching the finish line; Society wins by protecting the victim.

The lessons are clear. A victim who is alert and keeps looking is harder to harm. Society that acts early, at the ‘warning’ stage, protects better than one that waits for ‘danger’. When society fails, the victim is left alone, and in circle time students often say how bad that felt.

In real life:

  • Trust your feeling that something is wrong; say ‘No’ loudly, move away and go to a safe place.
  • Tell a trusted adult as soon as possible, even if you were told to keep it secret.
  • If you see someone being harassed, do not ignore it: stay near them, get an adult, call 1098 (child helpline) or 112 (emergency).
  • Never share personal details or photos with people you meet online.
Formulas to remember
  1. Personal safety rule: Say no, move away, tell a trusted adult.
  2. Emergency numbers in India: 1098 (child helpline), 112 (all emergencies).
Whensociety acts at the warning stageThenthe victim is protected before serious harm happens
Whena child is told to keep an uncomfortable touch secretThenthat is a warning sign and the child should tell a trusted adult at once

3Worked example

A senior keeps sending a classmate rude messages and says, ‘Don't tell anyone.’ What should the classmate do?
Step 1Do not reply and do not delete the messages; they are evidence.
Step 2Take screenshots and block the sender.
Step 3Tell a trusted adult such as a parent or class teacher the same day.
Step 4Remember that being asked to keep it secret is itself a warning sign.
Step 5If the adult does not help, tell another adult or call 1098.
More examples
  • A girl is followed home every day by an older boy; she tells her mother, who informs the school and the police.
  • A stranger in an online game asks a student for photos; the student blocks him and tells a parent.
  • In Char Tali, Society players at the warning line make an Aggressor flinch so the victim catches him.

4Your turn

In Char Tali, why is it better for Society to act at the warning line than at the danger line?

5Remember this

One line to keepYour body and space are yours; say no, move away and tell a trusted adult, and when others are at risk, act early.
Common mistake. Thinking harassment only counts if it is physical. Words, staring, following and online messages can all be harassment.
Topic 6 of 12
🔥6

Heat transfer by conduction: the Conduction Relay

By the end you canExplain conduction and use the words conductor and insulator to describe what happens in the relay.

1Think first

Why does a steel spoon in hot chai get hot at the handle, but a wooden spoon does not?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Heat always flows from a hotter object to a colder one. When the two objects touch, the heat passes directly through the contact: this is conduction. Materials that let heat pass easily are good conductors (metals such as steel, iron, copper and aluminium). Materials that slow heat down are poor conductors or insulators (wood, plastic, cloth, air). This is why a steel spoon in hot chai soon feels hot, while a wooden spoon does not, and why handles of pans are made of plastic or wood.

Your body is a heat source. Muscles that work hard produce a lot of heat, so after exercise your skin, especially your palms, is warm. In the Conduction Relay two teams of 5-6 stand 20 metres apart. Team A holds an object (say, a steel bottle) in their hands. On the second whistle each runner covers the 20 m in four parts: galloping for 5 m, hopping for 5 m, duck walking for 5 m and sprinting for the last 5 m, and then hands the object to a partner in Team B. Team B feels how warm the object has become. Then Team B does the same course holding the object wrapped in a handkerchief or towel, and Team A notices that this time the object is hardly warmed.

What happened? During the run, heat from warm hands flowed into the object by conduction. The cloth trapped air and acted as an insulator, so little heat reached the object. Teachers can repeat the relay with wooden, plastic and metal objects and at different times of day: a metal object left in the morning sun will feel hot even before the race.

How to run it well and safely:

  • Use objects that are smooth, unbreakable and not heavy; no glass.
  • Never use an object that has been lying in strong sun until it is too hot to hold.
  • Keep lanes separate so runners do not collide during the duck walk or sprint.
  • Duck walk with your back straight and stop if your knees hurt.

In circle time, describe which object felt warmest and explain why using the words conductor and insulator. Link it to sport: why do cricketers wear gloves, and why does a metal railing at the ground burn in May?

Formulas to remember
  1. Heat flows from a hotter body to a colder body.
  2. Conduction: transfer of heat through direct contact.
  3. Metals are good conductors; wood, plastic, cloth and air are poor conductors (insulators).
Whena warm hand holds a metal objectThenheat flows quickly into the object and it warms up
Whena layer of cloth is placed between hand and objectThenmuch less heat is conducted, because cloth and trapped air are insulators

3Worked example

Compare how warm a steel bottle and a plastic bottle become after the relay.
Step 1Before the run, touch both bottles and note that they feel about the same.
Step 2Run the 20 m course (gallop, hop, duck walk, sprint) holding the steel bottle and pass it on.
Step 3Your partner notes how warm it feels.
Step 4Repeat with the plastic bottle.
Step 5Conclusion: the steel bottle feels warmer because steel conducts heat from the hands better than plastic.
More examples
  • A steel water bottle left in the sun during a summer match becomes too hot to hold; a cloth cover keeps it cooler.
  • Batting gloves and goalkeeper gloves reduce heat and shock reaching the hands.
  • An aluminium bench at a bus stop feels colder than a wooden one on a winter morning, because metal conducts heat away from your body faster.

4Your turn

Why did the towel-wrapped object stay cool in the relay?

5Remember this

One line to keepHeat moves from hot to cold by contact; metals pass it on quickly, while cloth, wood and plastic slow it down.
Common mistake. Saying a blanket or towel ‘gives cold’ or ‘gives warmth’. It only slows the flow of heat; it does not create heat or cold.
Topic 7 of 12
🏃7

Linear, rotational and projectile motion: the Motion-in-Action Relay

By the end you canIdentify linear, rotational and projectile motion in sport and record measurements correctly in SI and CGS units.

1Think first

When a fielder throws the ball from the boundary to the wicket-keeper, why does it travel in a curve and not a straight line?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Every movement in sport is one of three kinds of motion, or a mix of them.

  • Linear motion: the body moves along a straight line, all parts covering the same distance in the same time. Example: a 100 m sprint.
  • Rotational motion: the body turns about a fixed point or axis. Example: a discus thrower spinning, a fielder spinning before a throw, a gymnast's somersault.
  • Projectile motion: an object is thrown into the air and then moves only under gravity, following a curved path called a parabola. Example: a cricket ball thrown from the boundary, a shot put, a long jumper in flight.

In the Motion-in-Action Relay, 4-5 teams rotate through three stations. Station 1: run a straight 20 m and record the time. Station 2: spin three times around a cone, then sprint to the next station, and record the time. Station 3: throw a softball at a target such as a bucket and measure how far it travelled. The fastest or best team at each station gets 5 points, the next 3 and the last 1, and points are added for the final result.

Measurements are written in two unit systems. In the SI system, length is in metres (m), mass in kilograms (kg) and time in seconds (s). In the CGS system, length is in centimetres (cm), mass in grams (g) and time in seconds. Time is the same in both. To convert length, use 1 m = 100 cm, so a throw of 14.5 m is 1450 cm.

Science behind the stations:

  • Speed in linear motion = distance ÷ time. A runner who covers 20 m in 4 s has a speed of 5 m/s (500 cm/s).
  • In rotation, a force towards the centre, the centripetal force, keeps you moving in a circle; you feel your feet and body leaning in. Dizziness after spinning comes from fluid in the inner ear that keeps swirling after you stop.
  • For a projectile, the angle of release and speed decide the distance. On flat ground, with air resistance ignored, an angle close to 45° gives the greatest range.

Safety: spin slowly at first and sit down if you feel very dizzy; throw only when the target area is clear and only on the teacher's signal; walk, never run, to collect balls.

Formulas to remember
  1. Speed = distance ÷ time
  2. 1 m = 100 cm; 1 kg = 1000 g; time in seconds is the same in SI and CGS
  3. For a projectile on level ground (no air resistance), the range is greatest near a 45° release angle.
Whenthe same distance is covered in less timeThenthe speed is greater
Whena ball is thrown much higher or much lower than about 45° on level groundThenit lands closer than its maximum range

3Worked example

At Station 1 Riya ran 20 m in 4.2 s; at Station 3 she threw the ball 15.8 m. Record her results in SI and CGS and find her running speed.
Step 1Time: 4.2 s in SI and 4.2 s in CGS (seconds are the same).
Step 2Throw: 15.8 m in SI; 15.8 × 100 = 1580 cm in CGS.
Step 3Speed = 20 m ÷ 4.2 s ≈ 4.76 m/s.
Step 4In CGS: 2000 cm ÷ 4.2 s ≈ 476 cm/s.
Step 5Write all values in the recording table with their units.
More examples
  • A runner covers 20 m in 4 s: speed = 20 ÷ 4 = 5 m/s = 500 cm/s.
  • A softball thrown 12.6 m is recorded as 12.6 m (SI) and 1260 cm (CGS).
  • A javelin, a basketball shot and a kicked football all follow a projectile path.

4Your turn

A shot put flying through the air is an example of which motion?

5Remember this

One line to keepSport is built from straight-line, turning and thrown motions, and every measurement needs its correct unit.
Common mistake. Converting time when changing from SI to CGS. Only length and mass change; time stays in seconds.
Topic 8 of 12
⚡8

Breathing, pulse and energy: Breathing in Action

By the end you canMeasure pulse and breathing rate and explain why both rise with harder exercise and fall during recovery.

1Think first

Why do you pant after climbing four floors of stairs quickly, but not after walking across the room?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

Muscles need energy to move, and they get most of it by using oxygen to break down food (mainly glucose). This releases energy, carbon dioxide and water. When you exercise harder, muscles need more oxygen and produce more carbon dioxide, so two things happen: you breathe faster and deeper, and your heart beats faster to pump oxygen-rich blood to the muscles. In very hard, short efforts the muscles also make some energy without enough oxygen, which is why you keep panting after a sprint while the body ‘repays’ the oxygen.

How to measure:

  • Pulse: place the tips of your index and middle fingers (not the thumb, which has its own pulse) on the thumb side of the inside of the wrist. This is the radial artery. Count the beats for 60 seconds, or for 15 seconds and multiply by 4. The answer is in beats per minute (bpm).
  • Breathing rate: count how many times your chest rises in 60 seconds (breaths per minute).

For a healthy 13-year-old at rest, the pulse is usually about 60-100 bpm and breathing about 12-20 breaths per minute; fitter students often have lower resting values.

In Breathing in Action, teams of 4-5 first sit quietly for one minute and record resting values. Then they move through three zones and record values after each: Zone 1 (low intensity) walking on the spot or light jogging for 2 minutes; Zone 2 (medium) jumping jacks or fast jogging for 1 minute; Zone 3 (high) a 30 m sprint or 30 seconds of burpees. Finally they sit for 3 minutes, checking the pulse every 30 seconds to see how fast it returns to resting. The quicker the return, the better the fitness.

StageBreaths/minPulse (bpm)
Resting1678
Zone 122102
Zone 230136
Zone 340168
After 3 min rest2094

Safety: students with asthma keep their inhaler nearby and may stay in Zone 2; stop if you feel faint. A useful breathing drill for recovery: breathe in through the nose for 3 counts and out through the mouth for 5.

Formulas to remember
  1. Pulse rate (bpm) = beats in 15 seconds × 4
  2. Food (glucose) + oxygen → energy + carbon dioxide + water
  3. Recovery: the faster the pulse returns to resting, the fitter the heart and lungs.
Whenexercise intensity increasesThenmuscles need more oxygen, so breathing and pulse rates rise
Whena person's heart and lungs get fitterThenresting pulse tends to drop and recovery after exercise is quicker

3Worked example

Measure your own pulse correctly after Zone 2.
Step 1Stop and sit or stand still.
Step 2Turn your left palm up and place your right index and middle fingertips on the thumb side of the wrist.
Step 3Press gently until you feel the beat.
Step 4Count beats for 15 seconds while a partner watches the clock.
Step 5Multiply by 4: 32 beats × 4 = 128 bpm. Record it in your chart.
More examples
  • A pulse count of 21 beats in 15 seconds gives 21 × 4 = 84 bpm.
  • A swimmer has to time breaths with strokes, so swimming trains breath control strongly.
  • After a 400 m race, an athlete keeps breathing hard for a few minutes even while standing still.

4Your turn

Why should you not use your thumb to count someone's pulse?

5Remember this

One line to keepHarder work needs more oxygen, so breathing and heart rate climb; how fast they come down shows how fit you are.
Common mistake. Counting the pulse for 15 seconds and forgetting to multiply by 4, then writing a pulse of 30 as if it were per minute.
Topic 9 of 12
🔬9

Neuromuscular control and flexibility: the Flex and React Challenge

By the end you canExplain how brain, nerves and muscles work together, and combine flexibility with quick, controlled responses.

1Think first

How does your hand know to close at exactly the right moment to catch a ball?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

No muscle moves on its own. Every movement starts as a signal from the brain (or, for reflexes, the spinal cord) that travels along motor nerves to the muscle fibres, telling them to contract. At the same time, sensors in muscles, tendons, joints, eyes and inner ear send information back to the brain about where your body is and how it is moving. This two-way teamwork of nerves and muscles is called neuromuscular control. Your sense of where your limbs are without looking is called proprioception; close your eyes and touch your nose to test it.

Good neuromuscular control gives quick reaction time (the time between a signal and the start of a response), accurate movements and good balance. It improves with practice: the more often a movement is repeated correctly, the smoother and faster the nerve pathway becomes. That is why a new skill feels clumsy at first and later feels automatic.

Flexibility is the range of movement at a joint. Flexible muscles let the body reach, twist and react without strain. But flexibility alone is not enough; you must also control the body in a stretched position.

The Flex and React Challenge joins the two. While holding a hamstring stretch, a student must catch a ball tossed gently to them. While holding a lunge, they must touch a cone when the teacher calls. Points are given for a good stretch (1 point), for a correct and quick response (1 point) and a bonus for doing both smoothly together (3 points). Later variations add balancing on one foot, a quick lunge on command, or pairs giving each other signals.

Doing it safely and well:

  • Warm up first; never stretch cold muscles hard.
  • Stretch only to mild tension, never to pain, and do not bounce.
  • In the lunge, keep the front knee over the ankle, not past the toes, and the back straight.
  • Throws must be gentle and underarm.

To judge progress, measure your sit-and-reach or count catches out of ten, repeat after a few weeks of regular practice, and compare. In circle time, think about everyday neuromuscular control: catching a falling glass, riding a cycle through traffic, or a batter adjusting to a ball that swings late.

Formulas to remember
  1. Neuromuscular control: brain and nerves send signals to muscles, and sensors send information back.
  2. Reaction time = time from the signal to the start of the response.
  3. Stretching rule: warm up first, stretch to mild tension, no bouncing, no pain.
Whena movement is practised correctly many timesThenthe nerve pathway becomes faster and the movement feels automatic
Whena muscle is stretched cold or bouncedThenthe risk of a strain increases

3Worked example

Try the hamstring-stretch catch with a partner.
Step 1After the warm-up, sit with one leg straight and the other bent, and reach gently towards the straight leg's toes.
Step 2Hold the stretch at mild tension; keep your back long.
Step 3Your partner, 2 m away, says ‘ready’ and tosses a soft ball underarm.
Step 4Catch it without coming out of the stretch, then return it.
Step 5Do 10 tries per leg, count catches, and repeat after two weeks to compare.
More examples
  • A slip fielder diving to catch an edge relies on fast reaction time and body control in a stretched position.
  • Touching your nose with eyes closed tests proprioception.
  • A beginner on a bicycle wobbles; after weeks of practice the nerve-muscle pathway makes balancing automatic.

4Your turn

What does proprioception allow you to do?

5Remember this

One line to keepMuscles move only when nerves tell them to; practice makes that signal faster, and flexibility gives it room to work.
Common mistake. Bouncing in a stretch to reach further. Bouncing triggers the muscle to tighten and can cause strain; hold the stretch still instead.
Topic 10 of 12
⚙️10

The musculoskeletal system: Move Like a Machine

By the end you canDescribe how bones, joints and muscles work together and perform four basic movement patterns with correct form.

1Think first

Why can your shoulder swing your arm in a full circle when your knee can only bend one way?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

The musculoskeletal system is the body's machine for movement. It has three main parts.

  • Bones (an adult has 206) form the frame, protect organs (the skull protects the brain, the ribs protect the heart and lungs) and act as levers.
  • Joints are where bones meet. Hinge joints such as the elbow and knee move mainly in one direction, like a door. Ball-and-socket joints such as the shoulder and hip move in many directions. A pivot joint in the neck lets the head turn. Ligaments hold bone to bone at a joint.
  • Muscles attach to bones through tough cords called tendons. When a muscle contracts it pulls the bone and the joint moves.

Joint movements have names. Flexion bends a joint and makes the angle smaller (curling the arm). Extension straightens it (straightening the arm). Pushing moves a load away from the body; pulling brings it towards the body. Balancing needs many small muscles around the ankle, knee, hip and trunk to make constant tiny corrections.

In Move Like a Machine, teams of 4-6 work around a circuit of four stations:

StationTaskWhat is working
1 Flexion and extensionBicep curls with a resistance band, water bottles or no equipmentBiceps (flex) and triceps (extend) at the elbow hinge
2 Jumping and landingSquat jumpsQuadriceps, gluteals, calves; hip, knee and ankle joints
3 Push and pullPush-ups or band pullsChest, shoulders, triceps; back muscles for pulling
4 BalancingOne-leg balanceAnkle and hip stabilisers, core

Teams score 3 points for finishing fastest, 1 for proper form and 1 bonus for encouraging one another, so good technique and teamwork count, not just speed.

Form and safety: in curls keep elbows by your sides and do not swing the back; in squat jumps land softly on the balls of the feet with knees bent and pointing over the toes; in push-ups keep the body in a straight line from head to heels (do them on the knees if needed); in balance, fix your eyes on one point. Stop if a joint, rather than a muscle, hurts.

Formulas to remember
  1. Tendon: joins muscle to bone. Ligament: joins bone to bone.
  2. Flexion bends a joint (angle decreases); extension straightens it (angle increases).
  3. Hinge joints (elbow, knee) move in one plane; ball-and-socket joints (shoulder, hip) move in many directions.
Whena muscle contracts and pulls on its tendonThenthe bone moves and the joint bends or straightens
Whenyou land from a jump with straight, locked kneesThenthe shock goes into the joints instead of being absorbed by the muscles

3Worked example

Do 10 slow bicep curls with two water bottles and describe what happens at the elbow.
Step 1Stand tall, a bottle in each hand, arms straight, elbows close to your sides.
Step 2Bend the elbows to bring the bottles to your shoulders: this is flexion, done by the biceps.
Step 3Lower slowly back down: this is extension, controlled by the triceps and biceps together.
Step 4Keep your back still; if you swing, the load is too heavy.
Step 5Name the joint (elbow, a hinge) and the two muscles you felt.
More examples
  • Lifting a school bag onto a shelf uses flexion at the elbow and the deltoid at the shoulder.
  • Bowling in cricket uses the ball-and-socket shoulder joint to swing the arm in a full circle.
  • A pull-up on a bar is a pull; a push-up is a push.

4Your turn

What connects a muscle to a bone?

5Remember this

One line to keepMuscles pull on bones through tendons, joints decide which way the bones can move, and together they work like a machine.
Common mistake. Mixing up tendons and ligaments. Tendon = muscle to bone; ligament = bone to bone.
Topic 11 of 12
🔬11

How the body adapts to training: Adapt and Achieve

By the end you canExplain how the body adapts to strength, endurance and flexibility training and why rest is part of training.

1Think first

If exercise tires and slightly damages muscles, why do they end up stronger?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

The body is not fixed; it adapts to what you regularly ask it to do. This is the whole reason training works. The key is a slightly bigger challenge than normal (called overload), repeated regularly, followed by enough rest.

  • Strength training (push-ups, squats, band pulls, carrying loads) makes muscles stronger and, over time, slightly bigger. Bones that are loaded, for example through jumping and weight-bearing work, also become stronger and denser. This matters at your age, because the bone strength you build in your teens helps you for life.
  • Endurance training (jogging, skipping, cycling, long walks) improves the heart, lungs and the muscles' ability to keep working without tiring. You can go further before getting out of breath.
  • Flexibility training (forward bends, lunges, shoulder reaches) gradually increases the range of movement at joints.
  • Recovery is where adaptation actually happens. Exercise causes tiny wear in muscle; during rest, sleep and good food, the body repairs it and builds back stronger. Without rest, you get tired, weaker and more prone to injury.

In Adapt and Achieve, small teams spend about five minutes at each of four stations: Strength (push-ups, squats or band pulls), Endurance (jumping jacks, running on the spot or rope skipping), Flexibility (forward bends, lunges, shoulder reaches) and Recovery (lying down for deep breathing or gentle stretching). There is no competition here. The aim is effort and personal best, and teachers may give recognition such as ‘Best Strength Effort’ or ‘Flexibility Star’.

Training sensibly:

  • Increase only a little at a time, for example 2-3 more push-ups or 1 more minute of skipping each week.
  • Use body-weight exercises at your age; heavy weights should only be used under expert supervision.
  • Do not train the same muscles very hard on two days in a row.
  • Sleep 8-10 hours, drink water, and eat dal, eggs, milk, curd, paneer, pulses, fruit and vegetables for repair.

To track adaptation, record a baseline (say, push-ups in one minute), train for four weeks, and test again. Link it to daily life: carrying groceries up stairs is strength, walking to school is endurance, and touching your toes to tie a shoelace is flexibility.

Formulas to remember
  1. Adaptation = overload (a little more than usual) + regular repetition + enough rest.
  2. Strength training: stronger muscles and bones. Endurance training: fitter heart, lungs and muscles. Flexibility training: greater range of movement.
  3. Progress rule: increase load gradually, a little each week.
Whenmuscles are regularly given a slightly bigger load than usual and then allowed to restThenthey repair and become stronger
Whentraining is done every day without enough rest or sleepThenperformance drops and the risk of injury rises

3Worked example

Plan a four-week push-up improvement for yourself.
Step 1Week 0: count how many correct push-ups you can do in 1 minute (say 10).
Step 2Train three times a week on non-consecutive days, doing 3 sets of about half your maximum (5) with a short rest between sets.
Step 3Each week add 1 push-up to each set if form stays good.
Step 4Rest, sleep and eat protein-rich food on other days.
Step 5Week 4: retest. A rise of 3-5 push-ups shows adaptation.
More examples
  • Aman could do 8 push-ups; after four weeks of three short sessions a week he does 13.
  • A student who skips rope daily notices she no longer gasps when climbing to the third floor.
  • A footballer who trains every day without rest keeps getting slower and picks up a hamstring strain.

4Your turn

During which part of training does the muscle actually rebuild stronger?

5Remember this

One line to keepChallenge the body a little, repeat it regularly and rest well: that is how muscles, bones, heart and joints adapt.
Common mistake. Believing that more training every day is always better. Without rest the body cannot adapt and injury becomes likely.
Topic 12 of 12
🔬12

Self-assessment, reporting concerns and personal growth

By the end you canAssess your own skills and attitudes honestly, set a specific goal, and know when and how to seek help.

1Think first

Is it more useful to rate yourself higher than you deserve or exactly as you are?No wrong answer. Think for a moment, then read on.

2The idea, in plain words

At the end of the unit you rate yourself on a simple 1-to-5 scale in several areas. Self-assessment is not a test with marks; it is an honest look in a mirror so that you can see where you are and choose what to improve next.

The areas include:

  • Appreciation for teammates: can you see a teammate's strengths and weaknesses, encourage them, and value that a team works best when members have different skills?
  • Overcoming bullying and overcoming harassment: do you stand up against it only sometimes, or confidently and every time, and do you seek help from a trusted adult?
  • Concepts of physics in PE: can you spot force, balance, motion and heat in an activity, and can you use them to play better?
  • Concepts of biology in PE: can you explain breathing, pulse, muscles and bones and apply them correctly?
  • Understanding muscles: can you name the main muscles in each activity, locate them, and notice when a classmate is struggling with a muscle problem and tell the teacher?

How to assess yourself well:

  • Base your rating on what you actually did, not what you wish you had done. Think of one real example for each rating.
  • Compare yourself with your own past, not with the best player in class.
  • Choose one area to improve and write a specific goal: ‘I will name the five muscles used in squats by next week’ is better than ‘I will learn muscles’.
  • Ask a teacher or friend if your rating seems fair.

Personal growth in PE also means looking after your mental health. Feeling nervous before a race, sad after losing, or left out is normal. But if you or a friend feel low, worried or angry most days, cannot sleep, stop enjoying things you used to like, or are being hurt by someone, that is a sign to talk to a trusted adult or school counsellor. In India, Tele-MANAS (14416) gives free mental health support, and 1098 helps children in difficulty. Asking for help is a sign of strength, just as an athlete asks a coach for help with technique.

Motivation, courage and discipline grow from small steps: turning up, trying a hard task, keeping a simple progress log, and celebrating improvement, your own and your teammates'.

Formulas to remember
  1. A good goal is specific, measurable and has a time limit.
  2. Warning signs to talk to an adult: feeling low or anxious most days, poor sleep, losing interest, being hurt by someone.
  3. Help lines in India: 14416 (Tele-MANAS, mental health), 1098 (child helpline).

3Worked example

Complete a self-assessment for ‘Concepts of physics in PE’ and set a goal.
Step 1Recall the Motion-in-Action Relay: could you name the three types of motion? If yes, at least level 1.
Step 2Did you use the idea of release angle to throw further? If not yet, you are at level 2.
Step 3Rate yourself 2 honestly.
Step 4Goal: ‘In the next three throwing sessions I will try 30°, 45° and 60° and record which goes furthest.’
Step 5Review the goal after three sessions.
More examples
  • Meera rates herself 3 in ‘Understanding Muscles’ and sets a goal of reaching 4 by labelling a muscle chart after each class.
  • A student realises he ignores teasing sometimes, rates himself 1 on bullying, and decides to report the next incident.
  • A boy notices a friend has stopped coming to play and seems low for weeks, and tells the class teacher.

4Your turn

Which is the best self-assessment goal?

5Remember this

One line to keepHonest self-rating and one clear goal at a time lead to real progress, and asking for help is part of growing strong.
Common mistake. Comparing yourself only with the best player in class. Progress is measured against your own earlier performance.

Key Concepts

Warm-up
Light activity and dynamic stretching before exercise that raises heart rate and prepares muscles and joints, reducing injury risk.
Cool-down
Slow activity, static stretching and deep breathing after exercise that brings the heart rate down gradually.
Circle time
The discussion at the end of a session where students reflect on technique, feelings and the idea learnt.
Centre of gravity
The point at which the whole weight of a body can be considered to act.
Base of support
The area enclosed by the parts of the body touching the ground; a wider base gives more stability.
Upstander
A bystander who chooses to take safe action to help someone who is being bullied.
Bystander
A person who sees bullying or harassment happening but does not act.
Harassment
Unwanted words, gestures, touch or messages that make a person feel uncomfortable, scared or unsafe.
Conduction
The transfer of heat from a hotter object to a colder one through direct contact.
Insulator
A material such as cloth, wood or plastic that slows the flow of heat.
Projectile motion
The curved motion of an object thrown into the air and moving under gravity.
Rotational motion
Motion in which a body turns about a fixed point or axis.
SI and CGS units
SI uses metre, kilogram and second; CGS uses centimetre, gram and second.
Pulse rate
The number of heartbeats per minute, felt at an artery such as the radial artery at the wrist.
Neuromuscular control
The teamwork of the brain, nerves and muscles that produces and adjusts movement.
Proprioception
The body's sense of where its limbs are and how they are moving without looking.
Tendon
A tough cord that attaches a muscle to a bone.
Flexion and extension
Flexion bends a joint and reduces its angle; extension straightens it.
Adaptation
The way the body becomes stronger, fitter or more flexible in response to regular training followed by rest.

End-of-Chapter Trial Paper & Test Questions

Topic-wise questions to test your understanding of every concept in this chapter.

  1. Which part of a PE session should include static stretches held for 15-30 seconds? (a) Warm-up (b) Main activity (c) Cool-down (d) Circle time / PE सत्र के किस भाग में 15-30 सेकंड तक रोके गए स्थिर खिंचाव (स्टैटिक स्ट्रेच) होने चाहिए? (a) वार्म-अप (b) मुख्य गतिविधि (c) कूल-डाउन (d) सर्कल टाइम
    Show answer

    (c) Cool-down — static stretches help muscles relax and the heart rate come down after activity; the warm-up uses moving (dynamic) stretches instead. / (c) कूल-डाउन — स्थिर खिंचाव गतिविधि के बाद मांसपेशियों को ढीला करने और हृदय गति कम करने में मदद करते हैं; वार्म-अप में गतिशील (डायनेमिक) खिंचाव किए जाते हैं।

  2. In the Horse Vault Race, the ‘horse’ is stable mainly because (a) it is moving fast (b) it has a wide base of support and a low centre of gravity (c) it holds its breath (d) it is taller than the jumper / घोड़ा कूद दौड़ में ‘घोड़ा’ मुख्य रूप से स्थिर क्यों रहता है? (a) वह तेज़ी से चल रहा है (b) उसका आधार चौड़ा और गुरुत्व केंद्र नीचा है (c) वह साँस रोके रहता है (d) वह कूदने वाले से लंबा है
    Show answer

    (b) it has a wide base of support and a low centre of gravity — four points on the ground and a low body make it hard to tip over. / (b) उसका आधार चौड़ा और गुरुत्व केंद्र नीचा है — ज़मीन पर चार बिंदु और नीचा शरीर उसे गिरने से बचाते हैं।

  3. A student who sees bullying and tells the class teacher is acting as (a) a bully (b) a target (c) a bystander (d) an upstander / जो विद्यार्थी धमकाने की घटना देखकर कक्षा अध्यापक को बताता है, वह किस भूमिका में है? (a) धमकाने वाला (b) पीड़ित (c) दर्शक (d) अपस्टैंडर (आगे बढ़कर मदद करने वाला)
    Show answer

    (d) an upstander — an upstander is a bystander who chooses to take safe action, such as reporting to a trusted adult. / (d) अपस्टैंडर — अपस्टैंडर वह दर्शक है जो सुरक्षित कदम उठाना चुनता है, जैसे किसी भरोसेमंद बड़े को बताना।

  4. In the Conduction Relay, why does the object wrapped in a towel stay cooler? (a) Cloth is a good conductor (b) Cloth is a poor conductor (insulator) of heat (c) The towel absorbs sweat only (d) Running cools the object / चालन रिले में तौलिए में लिपटी वस्तु ठंडी क्यों रहती है? (a) कपड़ा ऊष्मा का अच्छा चालक है (b) कपड़ा ऊष्मा का कुचालक (इंसुलेटर) है (c) तौलिया केवल पसीना सोखता है (d) दौड़ने से वस्तु ठंडी होती है
    Show answer

    (b) Cloth is a poor conductor (insulator) of heat — the cloth and the air trapped in it slow the flow of heat from the warm hands to the object. / (b) कपड़ा ऊष्मा का कुचालक है — कपड़ा और उसमें फँसी हवा गर्म हाथों से वस्तु तक ऊष्मा के प्रवाह को धीमा कर देते हैं।

  5. A softball is thrown 18 m. In CGS units this distance is (a) 18 cm (b) 180 cm (c) 1800 cm (d) 18000 cm / एक सॉफ़्टबॉल 18 मीटर फेंकी गई। CGS इकाई में यह दूरी है (a) 18 सेमी (b) 180 सेमी (c) 1800 सेमी (d) 18000 सेमी
    Show answer

    (c) 1800 cm — since 1 m = 100 cm, 18 m = 18 × 100 = 1800 cm. / (c) 1800 सेमी — क्योंकि 1 मीटर = 100 सेमी, इसलिए 18 मीटर = 18 × 100 = 1800 सेमी।

  6. Which structure attaches a muscle to a bone? (a) Ligament (b) Tendon (c) Cartilage (d) Nerve / कौन-सी संरचना मांसपेशी को हड्डी से जोड़ती है? (a) स्नायुबंधन (लिगामेंट) (b) कंडरा (टेंडन) (c) उपास्थि (कार्टिलेज) (d) तंत्रिका
    Show answer

    (b) Tendon — tendons carry the pull of a muscle to the bone; ligaments join bone to bone. / (b) कंडरा (टेंडन) — टेंडन मांसपेशी के खिंचाव को हड्डी तक पहुँचाता है; लिगामेंट हड्डी को हड्डी से जोड़ता है।

  7. A student counts 26 pulse beats in 15 seconds after jumping jacks. What is the pulse rate? (a) 26 bpm (b) 52 bpm (c) 104 bpm (d) 156 bpm / जंपिंग जैक के बाद एक विद्यार्थी 15 सेकंड में 26 नाड़ी धड़कनें गिनता है। नाड़ी दर क्या है? (a) 26 धड़कन/मिनट (b) 52 धड़कन/मिनट (c) 104 धड़कन/मिनट (d) 156 धड़कन/मिनट
    Show answer

    (c) 104 bpm — there are four 15-second periods in a minute, so 26 × 4 = 104 beats per minute. / (c) 104 धड़कन/मिनट — एक मिनट में 15 सेकंड के चार भाग होते हैं, इसलिए 26 × 4 = 104 धड़कन प्रति मिनट।

  8. Name the three types of motion and give one sports example of each. / गति के तीन प्रकारों के नाम लिखिए और प्रत्येक का खेल से एक उदाहरण दीजिए।
    Show answer

    Linear motion is movement in a straight line, such as a 100 m sprint. Rotational motion is turning about a fixed point or axis, such as a discus thrower spinning or a gymnast doing a somersault. Projectile motion is the curved path of an object thrown into the air and moving under gravity, such as a shot put, a javelin or a cricket ball thrown from the boundary. / रैखिक गति सीधी रेखा में चलना है, जैसे 100 मीटर की दौड़। घूर्णन गति किसी स्थिर बिंदु या अक्ष के चारों ओर घूमना है, जैसे चक्का फेंकने वाले का घूमना या जिमनास्ट की कलाबाज़ी। प्रक्षेप्य गति हवा में फेंकी गई वस्तु का गुरुत्व के कारण वक्र मार्ग है, जैसे गोला, भाला या सीमा रेखा से फेंकी गई क्रिकेट गेंद।

  9. Why do breathing rate and pulse rate rise during exercise, and what does recovery time tell us? / व्यायाम के दौरान श्वास दर और नाड़ी दर क्यों बढ़ती हैं, और रिकवरी का समय हमें क्या बताता है?
    Show answer

    Working muscles need more energy, which they get by using oxygen to break down food. So the body breathes faster and deeper to take in more oxygen and remove carbon dioxide, and the heart beats faster to carry oxygen-rich blood to the muscles. The harder the exercise, the higher both rates go. Recovery time is how long the pulse takes to return to its resting value after exercise; a shorter recovery time shows that the heart and lungs are fitter. / काम करती मांसपेशियों को अधिक ऊर्जा चाहिए, जो वे ऑक्सीजन की मदद से भोजन को तोड़कर प्राप्त करती हैं। इसलिए शरीर अधिक ऑक्सीजन लेने और कार्बन डाइऑक्साइड निकालने के लिए तेज़ और गहरी साँस लेता है, और हृदय ऑक्सीजन युक्त रक्त मांसपेशियों तक पहुँचाने के लिए तेज़ धड़कता है। व्यायाम जितना कठिन, दोनों दरें उतनी अधिक। रिकवरी का समय वह समय है जिसमें व्यायाम के बाद नाड़ी विश्राम स्तर पर लौटती है; कम समय का अर्थ है कि हृदय और फेफड़े अधिक स्वस्थ हैं।

  10. What should you do if you see a classmate being bullied? Describe safe actions an upstander can take. / यदि आप किसी सहपाठी को धमकाया जाता देखें तो आपको क्या करना चाहिए? एक अपस्टैंडर द्वारा उठाए जा सकने वाले सुरक्षित कदम बताइए।
    Show answer

    First, do not laugh, cheer or join in, and do not forward hurtful messages. Stay with the target or invite them to join your group so they do not feel alone, and tell them it is not their fault. If it is safe, say calmly, ‘Stop, this is not okay.’ Most importantly, report what you saw, with when and where, to a trusted adult such as the class teacher, counsellor or a parent. Avoid fighting the bully, as that can make it worse. In India, the child helpline 1098 can also help. / सबसे पहले, न हँसें, न उकसाएँ और न शामिल हों, और दुख पहुँचाने वाले संदेश आगे न भेजें। पीड़ित के साथ रहें या उसे अपने समूह में बुलाएँ ताकि वह अकेला महसूस न करे, और उसे बताएँ कि इसमें उसकी गलती नहीं है। यदि सुरक्षित हो तो शांति से कहें, ‘रुको, यह ठीक नहीं है।’ सबसे ज़रूरी है कि आपने जो देखा, कब और कहाँ, वह किसी भरोसेमंद बड़े जैसे कक्षा अध्यापक, परामर्शदाता या माता-पिता को बताएँ। धमकाने वाले से लड़ाई न करें, इससे स्थिति बिगड़ सकती है। भारत में चाइल्ड हेल्पलाइन 1098 भी मदद कर सकती है।

  11. Explain how the musculoskeletal system adapts to strength, endurance and flexibility training. Why is rest important? / समझाइए कि मांसपेशी-कंकाल तंत्र शक्ति, सहनशक्ति और लचीलेपन के प्रशिक्षण के अनुसार कैसे ढलता है। विश्राम क्यों ज़रूरी है?
    Show answer

    With strength training such as push-ups and squats, muscles become stronger and bones that bear load become stronger and denser. With endurance training such as jogging or skipping, the heart, lungs and muscles can keep working longer before tiring. With flexibility training such as forward bends and lunges, the range of movement at joints gradually increases. Rest is essential because exercise causes small wear in the muscles; during rest, sleep and good nutrition the body repairs this and builds back stronger. Without rest, performance falls and injuries become more likely. / पुश-अप और स्क्वाट जैसे शक्ति प्रशिक्षण से मांसपेशियाँ मज़बूत होती हैं और भार उठाने वाली हड्डियाँ अधिक मज़बूत और घनी होती हैं। जॉगिंग या रस्सी कूद जैसे सहनशक्ति प्रशिक्षण से हृदय, फेफड़े और मांसपेशियाँ बिना थके देर तक काम कर पाते हैं। आगे झुकना और लंज जैसे लचीलेपन के प्रशिक्षण से जोड़ों की गति का दायरा धीरे-धीरे बढ़ता है। विश्राम ज़रूरी है क्योंकि व्यायाम से मांसपेशियों में छोटी टूट-फूट होती है; विश्राम, नींद और अच्छे भोजन के दौरान शरीर इसकी मरम्मत करके उसे और मज़बूत बनाता है। विश्राम के बिना प्रदर्शन गिरता है और चोट की संभावना बढ़ती है।

Sourced from 0 content files · LLOS Learn · browse all chapters