Exploration: Entering the World of Secondary Science (Exploration: Secondary Science ki Duniya mein Kadam): Class 9 Science Chapter 1 Hinglish mein

Exploration · Hinglish notes, simulations aur practice · Official NCERT chapter PDF ↗

Published 13 Oct 2026 · Updated 13 Oct 2026

65 min
1 simulation
18 practice questions
21 MCQs

Is chapter mein aap kya seekhenge

Samajhna ki scientific knowledge kaise banti hai: observe karke, measure karke, patterns dhoondh kar, model bana kar, predict karke, test karke aur revise karke
Kisi sawaal ke liye simple model banana, yeh chun kar ki kaun si details rakhni hain aur kaun si chhodni hain, aur assumptions ko justify karna
Scientific terms, symbols aur SI units ko sahi-sahi use karna, aur equation ko is baat ka statement samajh kar padhna ki quantities aapas mein kaise judi hain
Scientific law, theory aur principle mein fark karna, aur samjhana ki theory koi guess kyun nahi hai
Kisi claim ya prediction ko measurable evidence aur pichhle patterns maang kar testable banana
Samjhana ki predictions fail hone par science khud ko kaise sudhaarti hai, aur mechanism aur evidence pooch kar kisi viral claim ko check karna
Kisi quantity ko hisson mein tod kar rough estimates lagaana, aur unhe jaane-pehchaane bounds se check karna
Dikhaana ki ek asli problem science ki kai branches aur doosre subjects ka sahaara kaise leti hai

NCERT Science Class 9, Chapter 1, pp. 1–7 par based original companion text. Yeh NCERT se juda nahi hai aur NCERT ne ise endorse nahi kiya hai.

1.1 Hum kaise jaante hain, yeh explore karna

June ki ek shaam tumhari dadi aasmaan dekhti hain, geeli hawa soonghti hain aur kehti hain ki ek hafte ke andar baarish aa jaayegi. Usi raat India Meteorological Department announce karta hai ki monsoon paanch-chhah din mein tumhare state tak pahunch jaayega. Dono sahi nikal sakte hain. Lekin sirf ek hi tumhe dikha sakta hai ki use kaise pata hai: kaun se measurements liye gaye, kaun sa pattern use hua aur forecast kitna pakka hai.

Yahi fark, kuch jaanne aur yeh dikha paane ke beech ki tum use kaise jaante ho, secondary science ki theme hai. Pichhli classes se jo curiosity tum laaye ho, wahi ab bhi sab kuch chalati hai. Badalta yeh hai ki ab har jawaab ke saath ek doosra sawaal juda aata hai: Hum kaise jaante hain, aur kitna pakka keh sakte hain?

Dekho, weather office ne apna forecast kaise kamaaya. Weather stations ne badhti humidity aur girta air pressure record kiya, yaani jo log mehsoos karte hain use numbers mein badla. Dashakon ke aise records ne ek pattern dikhaya jo monsoon aane se pehle aata hai. Us pattern ko equations mein likha gaya aur atmosphere ke ek computer model mein daala gaya. Ab model ne prediction kar diya hai, asli baarish use test karegi, aur agar woh chook gaya to model ko adjust kiya jaayega. Fig. 1.1 isi loop ko playground ke ek jhoole ke saath follow karta hai. Is loop ka baar-baar chakkar lagaana hi woh tareeka hai jisse scientific knowledge badhti hai.

7/7Idea ko rakho, behtar karo ya chhod do, phir ek zyada sharp sawaal ke saath dobara chakkar lagao.

Fig. 1.1Scientific exploration ka loop, ek example ke saath: jhoola.

'kaise pata?' shabdon ke chaaron taraf ek loop par saat gol-kone wale boxes hain, aur beech mein example ke liye playground ka ek jhoola hai. Step 1 mein sirf 'observe' dikhta hai, example 'jhoola dekho' ke saath. Step 2 mein 'measure' aur example 'ek swing: 2.8 s' judta hai. Step 3 mein 'pattern dekho' judta hai: lambi rope se swing dheema hota hai. Step 4 mein 'use maths' judta hai aur dikhaya jaata hai ki swing ka time rope ki length ke square root ke saath badhta hai. Step 5 mein 'model banao' judta hai: string par ek bob. Step 6 mein 'predict, test' judta hai: chaar guna rope se do guna time aana chahiye. Step 7 mein 'revise' judta hai aur usse 'observe' tak wapas ek dashed arrow jaata hai, jo loop ko band karta hai.

Tumhari Exploration textbook har page number ko do chhoti drawings ke beech rakhti hai: ek magnifying glass aur ek compass. Inhe do aadatein samjho jo poore saal saath rakhne laayak hain. Lens ka matlab hai dhyaan se dekhna, taaki tum woh details aur patterns notice karo jinke paas se doosre bas guzar jaate hain. Compass ka matlab hai direction. Ek achhi explorer jaanti hai ki woh kya pata lagaana chahti hai, kaam ke hisaab se sahi tool chunti hai, aur notice karti hai jab woh apne map ke kinaare se bahar nikal gayi ho. Dono drawings milkar us tarah ki exploring batati hain jo yeh book tumse chahti hai.

Quick check

2 mein se 1

Ek dost kehta hai, 'Science bas yaad karne wale facts ki list hai.' Secondary stage is picture mein kya jodta hai?

Yaad karne ke liye mushkil facts ki aur lambi listAise experiments jinhe tum bina soche follow karte hoFacts kaise dhoondhe, test kiye aur kabhi-kabhi badle jaate hainAise facts jo fixed hain aur jin par kabhi sawaal nahi uthta

Answer dekho

Answer (C) Facts kaise dhoondhe, test kiye aur kabhi-kabhi badle jaate hain

Focus is par hai ki knowledge kaise banti hai: measure karna, patterns dhoondhna, model banana aur test karna. Facts ki lambi list baat ko miss karti hai, kyunki naya evidence aane par facts badal sakte hain.

1.2 Models: sirf zaroori cheezein rakhna

Ek shehar itna complicated hai ki use ek saath samajhna mumkin nahi: laakhon log, sadkein, pipes, wires, ped aur traffic, aur sab kuch har minute badal raha hai. Nature bhi jahan dekho waisa hi hai. Isliye scientists shayad hi kabhi kisi asli system ko uski har detail ke saath study karte hain. Iske bajaay woh ek model (मॉडल) banate hain: asli cheez ka ek simplified version jo sirf wahi rakhta hai jo ek khaas sawaal ke liye zaroori hai.

Tum pehle se models use karte ho. Metro map stations ko dots ki tarah aur har line ko ek seedhi rangeen patti ki tarah dikhata hai. Asli tracks mudte hain aur distances galat hain, phir bhi yeh map is sawaal ke liye perfect hai: Mujhe train kahan badalni hai? Globe har building ko chhupa deta hai aur Himalaya ko ek halke se ubhaar mein badal deta hai, phir bhi woh is sawaal ka jawaab deta hai: Kolkata mein Sun Mumbai se pehle kyun ugta hai?

Models kai roop mein aate hain. Kuch drawings hote hain, jaise food chain jo poore jungle ko grass se deer aur deer se tiger tak kuch arrows mein sameta deti hai. Kuch aisi cheezein hoti hain jinhe tum haath mein pakad sakte ho, jaise ball-and-stick kit jo dikhata hai ki atoms judkar molecule kaise banate hain. Kuch equations hote hain, aur kuch computers ke andar chalte hain, jaise weather models jinhe forecasters roz use karte hain.

3/4Train ko 60 km/h se chalta ek dot maano: 120 km mein 2 hours lagte hain.

Fig. 1.2Railway app ka model: 'train kab pahunchegi?' sawaal ke liye poori train ek chalte dot mein simat sakti hai.

Upar ka sawaal poochta hai ki train station C kab pahunchegi. Step 1 mein coaches, windows aur passengers wali ek bani hui train hai, jiske colour, seats aur logon ke labels hain. Step 2 un labels ko kaat kar halka kar deta hai aur woh do details jodta hai jo matter karti hain: train apne route par kahan hai, aur kitni tez chal rahi hai. Step 3 train ko ek seedhi line par ek akele dot se badal deta hai; line par A 0 km par, B 60 km par aur C 120 km par marked hain, dot 60 km/h se chalta hai, isliye 120 km mein 2 hours lagte hain. Step 4 B par 10 minute ka halt jodta hai, yeh zyada detail wala model 2 hours 10 minutes deta hai.

Definition

Model

Kisi asli object, system ya process ka simplified version jo sirf wahi features rakhta hai jo ek khaas sawaal ka jawaab dene ke liye chahiye.

ExampleRailway app poori train ko stations ki line par chalte ek dot ki tarah dikhata hai.

Model banane ka matlab hamesha assumptions (मान्यता) lena hota hai: aise statements jinhe hum haath ke kaam ke liye kaafi sach maan lete hain. Fig. 1.1 ka swing model maanta hai ki rope khinchti nahi aur hawa jhoole ko mushkil se dheema karti hai. Camera traps se kisi reserve mein tigers ki ginti ka estimate lagaane wala wildlife scientist maanta hai ki har tiger ke camera ke saamne se guzarne ka chance barabar hai. Koi bhi assumption poori tarah sach nahi hai, phir bhi dono poochhe gaye sawaal ke liye kaafi achhe hain.

To achha model woh nahi jismein sabse zyada detail ho. Achha model woh hai jiski chhooti hui details us jawaab ko nahi badalti jo tumhare liye zaroori hai. Kuen mein giraye gaye bhaari patthar ke liye hawa ko ignore karna achha kaam karta hai, lekin girte pankh ke liye wahi shortcut bekaar jawaab deta hai. Simple models jaldi use hote hain aur unse sochna aasaan hota hai; jab humein zyada accuracy chahiye, to hum details ek-ek karke wapas jodte hain, jaise Fig. 1.2 ka aakhri step dikhata hai.

Example 1.1NCERT Example 1.1 · p. 2

Paper ki ball aur dustbin

Free period mein tum apni desk se, lagbhag 4 m door, kaagaz ki ek muchdi hui ball dustbin mein phenkne ki koshish karte ho. Tumhe ek simple model chahiye jo bataye ki ball bin mein giregi ya nahi. Kaun si details rakhoge, kaun si ignore karoge, aur kin par do baar sochoge?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

Activity 1.1NCERT Activity 1.1 · p. 2

Bharti hui balti ka model

Tumhe chahiye

ek balti jiska volume tumhe pata hai (aksar uski side par bana hota hai)
1 litre ki ek khaali bottle
ek nal
phone ki stopwatch ya seconds wali sui ki ghadi

Pehle guess karo

Tumhari 1 litre ki bottle nal se 8 seconds mein bharti hai. Simple model se batao, usi nal se 15 litre ki balti kitni der mein bharni chahiye?

Lagbhag 15 secondsLagbhag 2 minutesLagbhag 8 secondsLagbhag 15 minutes

Apna sawaal likho: Is nal se meri balti bharne mein kitna time lagega?
Jitni details soch sakte ho, sab likho: nal kitna khula hai, balti ka volume, uska colour aur shape, woh kis cheez ki bani hai, din ka kaun sa time hai, aur building mein koi aur paani use kar raha hai ya nahi.
Table mein details ko sort karo: rakhna hai ya ignore karna hai, aur kyun.
Nal poora kholo aur time naapo ki bottle bharne mein kitna time leti hai. Balti ka time predict karo: balti ka volume litres mein × seconds per litre.
Nal utna hi kholo, balti bharo aur uska time naapo. Naape gaye time ko apne prediction se compare karo.

Table 1.1Model ko kaun si details chahiye?

Detail	Rakhna hai ya ignore karna hai, aur kyun?
Nal kitna khula hai
Balti ka volume
Balti ka colour
Balti ki shape
Usi time doosre log paani use kar rahe hain

Tumhari entries apne aap save hoti hain.

Table 1.2Prediction aur test

Item	Time (s)
Bottle (1 L), naapa gaya
Balti, predicted
Balti, naapa gaya

Tumhari entries apne aap save hoti hain.

Model time = volume × seconds per litre ko sirf do numbers chahiye, phir bhi yeh aksar asli time ke kaafi kareeb pahunchta hai. Colour, shape aur material ko ignore kiya ja sakta hai kyunki woh yeh nahi badalte ki har second kitna paani behta hai. Isiliye unhe ignore karna kaam ka hai: problem jaldi solve ho jaati hai.

Agar tumhara naapa gaya time kaafi zyada tha, to dekho model ne kya ignore kiya. Ho sakta hai padosi ka nal chalne se water pressure gir gaya ho, ya balti mein uske label se zyada paani aata ho. Model ko asliyat se check karna batata hai ki kaun si detail wapas jodni hai. Baad mein paani ko paudhon ya safaai ke liye use karo, taaki kuch bhi barbaad na ho.

Ek scientist se milo

Meghnad Saha: star ek garam gas ki tarah

1900s ki shuruaat tak astronomers hazaaron stars ko unki light ki dark lines ke hisaab se classes mein sort kar chuke the. Har class mein alag-alag elements ki lines dikhti thi, aur kai astronomers maan lete the ki stars bas alag-alag materials se bane hain. Classes ka order koi samjha nahi paaya.

1920 mein Kolkata ke ek young physicist, Meghnad Saha (1893–1956), ne ek bold shortcut try kiya. Unhone star ke andar ho rahi lagbhag har cheez ko ek taraf rakha aur uski bahari layer ko ek garam gas ki tarah socha jise sirf do quantities batati hain: temperature aur pressure. Phir unki equation ne bataya ki aisi gas mein atoms ka kitna hissa electrons kho kar ions ban jaata hai. Zyada garam stars apne zyada atoms ko ionise karte hain, isliye alag lines dikhti hain. Star classes ka sequence mainly temperature ka ek scale nikla, alag-alag ingredients ki list nahi.

Baad mein Saha ne Kolkata mein woh institute shuru kiya jo aaj unke naam par hai, Saha Institute of Nuclear Physics, aur us committee ko lead kiya jisne India ke national calendar ko reform kiya.

1.3 Science ki bhasha: words, symbols aur units

Kisi dost se poochho ki uska weight kitna hai, to tumhe kuch aisa sunne ko milega: '48 kilo'. Ek scientist pyaar se batayega ki kilogram mass naapta hai, yaani kisi body mein matter ki maatra. Weight us mass par Earth ka khinchaav hai. Yeh ek force hai, aur forces newtons mein naape jaate hain.

Roz ke kai words ka science mein zyada sharp matlab hota hai (Table 1.3). Yeh nakhra nahi hai. Science un logon ke beech ki baatcheet hai jo shayad kabhi milein bhi nahi: Bengaluru ka ek chemist, Nairobi ka ek doctor, pachaas saal baad wahi report padhne wala ek student. Agar ek word ke do matlab ho sakte hain, to results gadbad ho jaate hain. Isliye scientists exact terms, standard symbols aur standard units par sehmat hote hain.

Table 1.3Roz ke words jinka science mein ek precise matlab hai

Shabd	Roz ki baatcheet mein	Science mein
weight	koi cheez kitni bhaari hai, kg mein bola jaata hai	kisi body par gravity ka force, newtons mein
pressure	tension, jaise 'exam ka pressure'	har unit area par lagne wala force
solution	kisi problem ka jawaab	ek uniform mixture, jaise paani mein ghuli cheeni
culture	kisi samaaj ka music, khaana aur reeti-rivaaz	dish ya tube mein jaan-boojh kar ugaaye gaye microbes
theory	andaaza ya guess	evidence se supported, achhi tarah test ki gayi explanation

Physical quantity (भौतिक राशि) koi bhi aisi cheez hai jise hum naap sakein aur unit ke saath number mein bata sakein: length, mass, time, temperature, electric current. Har ek ka ek agreed symbol hota hai, jaise mass ke liye $m$ , time ke liye $t$ aur speed ke liye $v$ . Quantities ke symbols tirchhe (italic) chhapte hain aur units seedhe. To $m = 5 k g$ mein tirchha $m$ quantity mass hai, jabki kg uski unit, kilogram hai. Seedha m, jaise 5 m mein, unit metre hai.

India, lagbhag har desh ki tarah, International System of Units use karta hai: SI units (SI मात्रक). Sirf saat base units ki zaroorat hoti hai (Table 1.4); baaki har unit inhi se banti hai. Jaise speed metres per second ( $m / s$ ) mein naapi jaati hai.

Table 1.4Saat SI base units

Quantity	Symbol	SI unit (symbol ke saath)
length	$l$	metre (m)
mass	$m$	kilogram (kg)
time	$t$	second (s)
electric current	$I$	ampere (A)
temperature	$T$	kelvin (K)
amount of substance	$n$	mole (mol)
luminous intensity	$I_{v}$	candela (cd)

4/42019 se kilogram Planck constant se define hota hai, jo har jagah same hai.

Fig. 1.3Kilogram har jagah same kyun hai: har weight ko check-dar-check ek agreed definition tak wapas trace kiya ja sakta hai.NCERT Fig. 1.1 · p. 3

Chaar cheezein ek line mein hain, har ek agli wali se check hoti hai. Step 1 mein sirf dukaan ka iron ka 1 kg weight hai, jis par 'apna bazaar' likha hai. Step 2 mein ek pan balance judta hai jis par 'state standard' aur 'inspectors' likha hai, aur dukaan ke weight se uski taraf ek arrow hai. Step 3 mein glass cover ke neeche rakha ek metal cylinder judta hai, New Delhi ke NPL mein rakha national kilogram. Step 4 mein letter h wali ek ring judti hai, yaani Planck constant, nature ka ek constant jo 2019 se kilogram ko define karta hai.

Mathematics: relationships ki bhasha

Jab quantities aa jaati hain, to sirf words se baat bhaari ho jaati hai. Ek sentence mein batane ki koshish karo ki steady speed par ek scooter kitne bhi minutes mein kitni door jaata hai. Mathematics yeh paanch symbols mein kar deta hai:

Average speed

v = \frac{d}{t}

(1.1)

jahan

$v$: average speed
$d$: tay ki gayi distance
$t$: laga hua time

Har letter ek measurable quantity ke liye hai, aur equals sign ek vaada karta hai: same time mein tay ki gayi distance double karo, to speed bhi double ho jaati hai. $d = v t$ ke roop mein rearrange karne par wahi line tumhare chune kisi bhi time ke liye distance deti hai; $t = d / v$ ke roop mein, kisi bhi distance ke liye time deti hai. Ek chhoti si line mein jawaabon ki poori family samaayi hai.

Equations sochne ki jagah nahi leti; woh soch ko organise karti hain. Kisi equation tak pahunchne se pehle poochho ki kya ho raha hai, kaun si quantities matter karti hain aur unmein se kaun si tumhe pehle se pata hain. Neeche ka worked example bilkul isi order ko follow karta hai.

Example

Kya tum train pakad paoge?

Tumhari train 7:40 a.m. par chhootti hai. Station ghar se 6 km door hai, aur subah ke traffic mein autorickshaw ki average speed lagbhag 24 km/h rehti hai. Agar tum 7:20 a.m. par niklo, to kya pahunch jaoge?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

Quick check

3 mein se 1

Ek ladki ka mass 50 kg hai. Kaun sa statement weight word ko uske scientific matlab mein use karta hai?

Uska weight 50 kg haiUska weight yeh hai ki woh kitna bhaari mehsoos karti haiThakne par uska weight badal jaata haiUska weight us par Earth ka khinchaav hai, lagbhag 490 N

Answer dekho

Answer (D) Uska weight us par Earth ka khinchaav hai, lagbhag 490 N

Weight kisi body par gravity ka force hai, jo newtons mein naapa jaata hai: lagbhag

50 \times 9.8 = 490

N. '50 kg' uska mass hai, aur yahi roz ki gadbad hai.

1.4 Laws, theories aur principles

Ek glass paani mein ek chammach namak ghol do, to namak gaayab sa ho jaata hai. Phir bhi agar tum glass, paani aur namak ko gholne se pehle saath mein tolo, aur phir baad mein dobara, to reading nahi badalti (Fig. 1.4). Cheeni ke saath try karo. Kasakar band bottle mein vinegar aur baking soda try karo, jahan gas ke bubbles uthte hain. Total mass phir bhi same rehta hai. Aise patterns se nikalne wale ideas ke liye science ke paas teen words hain: law, theory aur principle.

4/4Theory: matter particles se bana hai; namak ke particles paani ke particles ke beech phail jaate hain aur koi kho nahi jaata.

Fig. 1.4Law pattern batata hai; theory use samjhaati hai.

Ek digital balance par paani ka ek glass aur namak ki ek chhoti dish rakhi hai. Step 1, jis par 'paani+namak' likha hai, dish mein namak ka dher aur reading 250 g dikhata hai. Step 2, 'namak ghula', khaali dish, paani mein namak ke kuch halke kan aur wahi 250 g reading dikhata hai, jis par 'same' likha hai. Step 3 ek box jodta hai: 'LAW: kya hota hai, mass pehle = mass baad'. Step 4 'THEORY: why' aur ek magnified circle jodta hai, jismein gol paani ke particles aur chaukor namak ke particles saath mein mile hue hain, koi bhi gaayab nahi.

Scientific law (नियम) ek chhota statement ya equation hai jo nature ke us kaam ka saar batata hai jo woh har ek baar karti hai. Upar wala pattern law of conservation of mass hai: closed system mein kisi bhi change se pehle ka total mass uske baad ke total mass ke barabar hota hai. Law tumhe bharose se batata hai ki kya hota hai. Woh yeh nahi batata ki kyun.

Pattern jaan lene ke baad bhi ek puzzle bachti hai: namak gaya kahan, aur balance ko pata kyun nahi chalta? Scientific theory (सिद्धांत) is tarah ke sawaalon ka jawaab deti hai, yaani pattern ke peechhe ka kyun. Particle theory of matter kehti hai ki namak, paani aur baaki sab kuch chhote-chhote particles se bane hain. Jab namak ghulta hai, to uske particles paani ke particles ke beech phail jaate hain. Na koi naya banta hai na koi nasht hota hai, isliye mass same rehta hai. Theory kai saalon mein jama kiye gaye evidence par tiki hoti hai, aur use is baat se parkha jaata hai ki woh kitna samjhaati hai aur uski predictions kitni achhi tarah sahi nikalti hain.

Scientific principle ek general idea hai jiski pahunch bahut door tak hoti hai: ek baar jaan lo, to use un cases par bhi laga sakte ho jo tumne pehle kabhi nahi dekhe. Archimedes' principle kehta hai ki liquid ya gas mein rakhi body ko ek upward force dhakelta hai, jo us fluid ke weight ke barabar hota hai jise body hatati hai. Yahi ek idea samjhata hai ki steel ka ship kyun tairta hai, swimming pool mein tum halka kyun mehsoos karte ho aur hot-air balloon upar kyun uthta hai.

Compare

Law, theory aur principle

Law

Pattern batata hai: kya hota hai
Aksar ek statement ya equation
Jaise: conservation of mass

Theory

Samjhaati hai ki pattern kyun hota hai
Kai laws aur observations ko ek saath jodti hai
Jaise: particle theory of matter

Principle

Ek broad idea jo kai situations mein use hota hai
Naye case ke baare mein sochne mein madad karta hai
Jaise: Archimedes' principle

Log kabhi-kabhi kisi idea ko yeh keh kar taal dete hain, 'Arre, woh to bas ek theory hai.' Yahi baat germ theory of disease ke baare mein keh kar dekho, jo kehti hai ki kai bimaariyaan microbes se hoti hain. Isi ki wajah se hum peene ka paani ubaalte hain, haath dhote hain aur bachchon ko vaccine lagwaate hain, aur yeh hazaaron tests paas kar chuki hai. Science mein kisi idea ko theory kehna taarif hai, kandhe uchkaana nahi: yeh word un explanations ke liye rakha jaata hai jinhe kadaai se check kiya gaya aur jo phir bhi tiki hain.

Phir bhi koi theory kabhi poori declare nahi ki jaati. 1808 ki atomic theory atoms ko aisi solid balls maanti thi jinhe toda nahi ja sakta. Ek sadi ke andar experiments ne unke andar electrons dhoondh liye, aur theory dobara banayi gayi (atom ki timeline). Jis explanation ko evidence behtar bana sake, woh kabhi na badalne wale vishwaas se zyada bharose laayak hai, kam nahi.

Quick check

2 mein se 1

Har term ko uske kaam se match karo.

Left mein koi item tap karo, phir right mein uska match.

Answer dekho

Answer

Law : Pattern batata hai: kya hota hai
Theory : Samjhaati hai ki pattern kyun hota hai
Principle : Kai cases par lagne wala broad idea
Model : Ek sawaal ke liye simplified picture

Law pattern batata hai, theory use samjhaati hai, principle ek broad idea hai jise door tak lagaya ja sakta hai, aur model jaan-boojh kar simplify ki gayi picture hai.

1.5 Predictions: science aage dekhti hai

Astronomers abhi se un solar eclipses ki dates aur times list kar sakte hain jo tumhare dada-dadi banne ke bhi kaafi baad honge. Leh ka ek cook bina try kiye jaanta hai ki wahan khule bartan mein dal pakne mein zyada time lagta hai, kyunki us oonchaai par paani 100 °C ki jagah lagbhag 88 °C par ubalta hai. Yeh predictions (पूर्वानुमान) hain: aage kya hoga, iske baare mein statements, jo laws, theories aur models se pehle hi nikaale jaate hain.

Sun dikhata hai ki yeh kyun zaroori hai. Us par koi experiment nahi kar sakta, phir bhi woh apna fuel kaise jalata hai, iske models humein batate hain ki woh arabon saal tak chamakta rahega. Isi tarah engineers ek bhi girder lagne se pehle nikaal lete hain ki pul kitna load utha sakta hai, aur doctors lagbhag jaante hain ki sahi dawai ke baad bukhaar kab utarna chahiye.

Prediction ko guess se jo cheez alag karti hai, woh yeh hai ki uski reasoning saamne rakhi hoti hai taaki koi bhi check kar sake. Phir aakhri faisla nature ka hota hai. Maan lo Leh ki cook apni dal ka time naapti hai aur paati hai ki woh Delhi se dheere nahi pakti. Reasoning ka koi hissa fail hua hai, aur kaam ka sawaal yeh hai ki kaun sa: shayad uska bartan shuru se pressure cooker tha (ek assumption), ya uska thermometer kharab tha (ek measurement). Failure ki wajah dhoondhna aksar success se zyada sikhaata hai (Section 1.6).

SimulationMoon ka phase predict karo

Upar se dekhi gayi Earth, jiske chaaron taraf Moon ghoom raha hai aur ek taraf se sunlight aa rahi hai. Ek inset dikhata hai ki Earth se Moon kaisa dikhta hai, aur readouts date, dinon mein Moon ki age aur uske phase ka naam batate hain. Buttons time ko ek-ek din aage ya peeche le jaate hain, taaki tum prediction karke use test kar sako.

Fig. 1.5Model jaanta hai ki Moon ko ek full moon se agle full moon tak lagbhag 29.5 din lagte hain. Pehle phase predict karo, phir aage step karke check karo.

Try karo

Aaj ka phase aur Moon ki age note karo. 7 din baad ka phase predict karo, phir check karne ke liye one-day step button saat baar dabao.
Agle full moon tak step karo. Uske baad wale full moon ki date predict karo, phir aage step karke apna prediction test karo.
Play dabao. Full moon ke theek baad kaun sa phase aata hai, aur new moon se theek pehle kaun sa?

Example 1.2NCERT Example 1.2 · p. 4

Kya May tak talaab sookh jaayega?

15 March ko Ishaan ke dada gaon ka talaab dekhte hain aur kehte hain, 'May ke beech tak yeh sookh jaayega, kyunki is baar sardi sookhi thi.' Ishaan kaun se sawaal pooch sakta hai jisse yeh ek testable prediction ban jaaye?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

Aage badhne ko taiyaarNCERT Aage Badhne ko Taiyaar · p. 4

Hum ek mahina aage ka weather forecast kyun nahi kar sakte?

Do pattiyon ko saath-saath ek naale mein daalo. Kuch seconds tak woh saath tairti hain; ek minute baad woh meeton door ho sakti hain, kyunki unki shuruaati jagah ke chhote-chhote fark paani ke har bhanwar ne kheench kar bada kar diye. Hawa bhi aise hi behave karti hai. Forecasters temperature, pressure, humidity aur hawa ki laakhon readings se shuru karte hain aur computer models ko time mein aage chalate hain. Shuruaati numbers ki chhoti galtiyaan model chalne ke saath badhti jaati hain, isliye kal ka forecast aksar achha hota hai, agle hafte ka thoda kachcha, aur agle mahine ka us season ke aam weather se zyada behtar nahi hota. Isiliye forecasts aksar vaada karne ki jagah baarish ka chance batate hain: model ko thodi alag-alag starting values se kai baar chalaya jaata hai, aur forecast batata hai ki un runs mein kitni baar baarish hui.

Quick check

2 mein se 1

Inmein se kaun sa prediction sabse zyada scientific hai?

'Aaj baarish hogi, kyunki maine abhi car dhoyi hai.''Baarah din se baarish nahi hui, to aaj to baarish pakki hai.''Mera horoscope kehta hai aaj baarish hogi, to hogi.''Humidity zyada hai aur pressure gir raha hai, jaise pichhle hafte ke toofaan se pehle hua tha.'

Answer dekho

Answer (D) 'Humidity zyada hai aur pressure gir raha hai, jaise pichhle hafte ke toofaan se pehle hua tha.'

Sirf aakhri wala naapi gayi quantities (humidity, pressure) aur pehle dekhe gaye pattern ko use karta hai. 'Baarish pakki hai' sunne mein theek lagta hai, lekin kisi evidence par nahi tika: baarish kisi schedule par nahi aati.

1.6 Limits, failures aur self-correction

Newton ke laws of motion aur gravitation ab tak likhe gaye sabse safal ideas mein se hain. Phir bhi unki bhi seemayein hain, aur woh seemayein kaise mili, yeh kahani science ko uske best roop mein dikhaati hai.

1840s mein astronomers ke saamne ek puzzle thi. Newton ke laws of motion aur gravitation planets ko khoobsoorati se describe karte the, phir bhi Uranus unke predict kiye raaste se thoda-thoda hatta jaata tha (Fig. 1.6). Ek option tha laws ko galat declare karna. Iske bajaay French mathematician Urbain Le Verrier ne ek assumption par sawaal uthaya: ki saare planets pehle se pata hain. Unhone calculate kiya ki Uranus ko raaste se kheenchne ke liye ek anadekha planet kahan hona chahiye. 23 September 1846 ko Berlin ke ek astronomer ne telescope us jagah ki taraf kiya aur Neptune dhoondh liya, predicted position se ek degree se bhi kam door.

4/41846 mein Neptune lagbhag theek wahin mila jahan Le Verrier ne predict kiya tha.

Fig. 1.6Ek fail prediction se naya planet mila (scale ke hisaab se nahi).

Upar se ek view, scale ke hisaab se nahi, left mein Sun aur ek curved line ke roop mein Uranus ke orbit ka hissa. Step 1 ek dashed ring dikhata hai jahan Newton ke laws ke hisaab se Uranus hona chahiye. Step 2 ek bhara hua dot jodta hai jahan Uranus asal mein dikhta hai, prediction se thoda hat kar, aur heading hai 'Uranus raaste se bhatka'. Step 3 ek dashed bahari orbit, ek question mark aur ek arrow jodta hai jo Uranus par ek chhupe planet ki taraf khinchaav dikhata hai. Step 4 question mark ki jagah Neptune dikhata hai, jo 1846 mein mila.

Phir Le Verrier ne dekha ki Mercury bhi gadbad kar raha tha: uska orbit dheere-dheere ek chhote se extra amount se ghoom raha tha jise Newton ke laws samjha nahi paate the. Unhone Sun ke paas ek aur chhupe planet ka prediction kiya, jiska nickname Vulcan pada. Astronomers dashakon tak dhoondhte rahe aur woh kabhi nahi mila. Is baar assumption theek tha; theory khud apni limit tak pahunch gayi thi. 1915 mein Albert Einstein ki general theory of relativity ne Mercury ke orbit ko bilkul sahi samjha diya. Newton ke laws aaj bhi satellites launch karne aur pul design karne mein use hote hain, lekin ab hum jaante hain ki woh kahan kaam karna band karte hain: bahut massive bodies ke paas aur light ki speed ke kareeb ki speeds par.

Relativity sirf astronomers ke liye nahi hai. Global Positioning System (GPS) ke satellites par lagi ghadiyaan zameen ki ghadiyon se har din lagbhag 38 millionths of a second tez chalti hain. Einstein ki theories se nikale correction ke bina tumhare phone par dikhne wali location har din lagbhag 10 km khisak jaati.

Dono mein se kisi bhi case mein koi famous hone ya zid par adne se nahi jeeta. Le Verrier ek mashhoor scientist the, phir bhi jab telescopes ko kuch nahi mila to unka Vulcan chhod diya gaya. Faisla planets ne kiya. Yahi science ka sauda hai: koi idea apni jagah tabhi tak rakhta hai jab tak evidence (साक्ष्य) uska saath deta rahe.

Curiosity ke dhaageNCERT Curiosity ke Dhaage · p. 5

Ek viral claim check karo

Tumhe chahiye

tumhare family ya class group mein forward kiya gaya koi claim
tumhari notebook

Family group par ek message aata hai: 'Microwave oven ka khaana kabhi mat khao. Microwaves use radioactive bana deti hain.' Forward karne se pehle use kuch scientific sawaalon se guzaaro, ek-ek karke.

Claim ka matlab kya hoga? Radioactive substance ke atoms unstable hote hain, jinke central cores (nuclei) toot kar radiation chhodte hain.
Microwaves karti kya hain? Yeh ek tarah ki radio wave hain. Yeh khaane ke water molecules ko tezi se hilaati hain, aur yahi hilna heat hai.
Kya koi mechanism hai? Microwave ka har chhota hissa jo energy le jaata hai, woh atom ke nucleus ko badalne ke liye bahut hi kam hai. Woh bas molecules ko hilaata hai, jo heat hai: wahi asar jo gas ki flame ka hota hai.
Kya kuch peechhe bachta hai? Oven band karo aur waves usi pal ruk jaati hain, jaise bulb band karte hi kamra andhera ho jaata hai.
Measurements kya kehte hain? Microwave mein garam kiye khaane ke paas rakha radiation detector wahi reading deta hai jo gas stove par pake khaane ke paas.

Table 1.5Mera claim check

Sawaal	Mera jawaab
Asal mein claim kya kiya ja raha hai?
Kya koi mechanism hai jo aisa kar sake?
Kaun sa evidence faisla kar dega?
Mera faisla

Tumhari entries apne aap save hoti hain.

Aisa koi raasta nahi hai jisse microwaves khaane ko radioactive bana sakein, aur measurements mein koi radioactivity nahi milti, isliye claim fail hota hai. Ek samajhdaari wali warning zaroor bachti hai: aadha-adhoora garam khaana thande hisse rakh sakta hai jahan germs rehte hain, isliye use chalao aur poora garam karo. 'Yeh kaise ho sakta hai?' aur 'Ise kya saabit karega?' poochhna lagbhag har afwaah par kaam karta hai.

Quick check

2 mein se 1

Engineers aaj bhi pul design karne ke liye Newton ke laws use karte hain, jabki light ki speed ke kareeb ki speeds par yeh laws fail ho jaate hain.

SahiGalat

Answer dekho

Answer Sahi

True. Newton ke laws apni limits ke andar ab bhi behtareen hain: pulon, cars, cricket balls aur satellite launches ke liye. Yeh jaanna ki koi theory kahan kaam karna band karti hai, use bekaar nahi, aur zyada kaam ka banata hai.

1.7 Estimation: rough numbers ke saath sochna

Ek forwarded message kehta hai ki ek average insaan din mein 50 litres paani peeta hai. Is par shak karne ke liye tumhe laboratory nahi chahiye. Ek glass mein lagbhag chauthaai litre aata hai, to 50 litres matlab lagbhag 200 glass, yaani jaagne se sone tak har paanch minute mein ek. Das second ka rough hisaab, yaani ek estimate (अनुमान), claim ko dubone ke liye kaafi tha.

Is jhatpat check ke peechhe ek routine hai jiski practice karna faayde ka hai: anjaani quantity ko aise hisson mein todo jinka andaaza laga sako (glass, ghante), har hisse ko ek round value do, multiply karo, aur result ko kisi jaani-pehchaani cheez se compare karo (Fig. 1.7).

Scientists lagaataar estimate karte hain, aksar kuch bhi exact calculate karne se pehle. Physicist Enrico Fermi iske liye mashhoor the: 1945 mein pehle atomic bomb test par unhone kaagaz ke tukde giraye, dekha ki blast ne unhe kitni door dhakela, aur jaldi se explosion ki rough strength nikaal li. Woh apne students ko aisi puzzles bhi dete the jaise 'Chicago mein kitne piano tuners kaam karte hain?', jiska jawaab kisi book mein nahi, par koi bhi soch kar nikaal sakta hai. Lambi calculation mein galat jagah laga decimal point bhi turant pakad mein aa jaata hai jab tumhe pehle se lagbhag pata ho ki jawaab kya hona chahiye.

4/4Body ka blood × din mein chakkar lagbhag 7200 L deta hai: dono raaste match karte hain.

Fig. 1.7Pehle jawaab ki seema tay karo, phir dekho ki do alag-alag raaste ek hi jagah pahunchte hain ya nahi. Line par har mark pichhle wale ka das guna hai.

Ek horizontal number line 1 se 1 000 000 litres tak jaati hai, har mark pichhle wale ka das guna. Step 1 line aur sawaal 'Ek din mein kitna blood?' dikhata hai. Step 2 10 litres, yaani ek balti, ko bahut kam bata kar kaat deta hai, aur ek million litres, yaani bada pool, ko bahut zyada bata kar. Step 3 route 1 se 7056 litres par ek dot jodta hai. Step 4 route 2 se 7200 litres par ek ring jodta hai, lagbhag pehle wale ke upar: dono raaste match karte hain.

Example 1.3NCERT Example 1.3 · p. 6

Tumhara dil ek din mein kitna blood pump karta hai?

Estimate karo ki tumhara dil ek din mein kitne litre blood pump karta hai. Exact nahi, ek reasonable value ka target rakho, aur use doosre raaste se check karo.

Pehle khud try karo. Phir solution ek-ek step karke kholo.

Aage badhne ko taiyaarNCERT Aage Badhne ko Taiyaar · p. 5

Tumhari family din mein kitna paani use karti hai?

Tumhe chahiye

tumhari notebook
jaane-pehchaane size ki ek balti aur ek mug (optional)

Ghar par paani ke main uses ki list banao: nahaana, flush karna, kapde aur bartan dhona, khaana banana aur peena. Har ek ke liye estimate karo ki ek baar mein kitne litre lagte hain (ek balti mein 15–20 L aata hai; ek flush mein 6–10 L lagta hai) aur din mein kitni baar hota hai. Multiply karo aur jodo.

Phir apne jawaab ki seemayein tay karo. Kya family 10 L roz mein kaam chala sakti hai? Usmein to ek balti wala snaan bhi nahi hota. Kya woh 10 000 L use kar sakti hai? Isse roz das badi overhead tankiyaan khaali ho jaatin. Sewer wale Indian shehron ke planners har insaan ke liye roz lagbhag 135 L maante hain, yaani chaar logon ki family ke liye lagbhag 540 L, isliye 1000 L ki tanki lagbhag do din chalegi.

Table 1.6Meri family ke paani ka estimate

Use	Har baar litres	Din mein kitni baar	Din ke litres
Nahaana
Toilet flush
Kapde dhona
Bartan dhona
Khaana banana aur peena
Total

Tumhari entries apne aap save hoti hain.

Quick check

3 mein se 1

Ek leak karta nal lagbhag har second ek boond tapkaata hai, aur 20 boondon se 1 mL banta hai. Woh din mein lagbhag kitne litre barbaad karta hai?

Answer dekho

Answer 4.3 L

Ek din mein

86 400

s hote hain, to lagbhag

86 400

boondein. Yeh

86 400 \div 20 = 4320

mL hai, yaani har din lagbhag 4.3 L barbaad.

1.8 Ek duniya, kai branches

Har sardi north India ke kai shehron par ek dhoosar dhundh chha jaati hai. Kyun, yeh poochho aur gino ki tumhe kitne subjects chahiye (Fig. 1.8). Physics samjhaati hai ki insaani baal se kam se kam bees guna patle particles hawa mein kaise tairte rehte hain. Chemistry batati hai ki gaadiyon, factories aur jalti fasal ki paraali se kaun si gases aur kaalikh nikalti hai, aur sunlight mein woh kaise react karti hain. Earth science samjhaati hai ki thandi, ruki hui sardi ki hawa dhundh ko zameen ke paas kyun kaid kar leti hai. Biology dikhaati hai ki sabse chhote particles lungs mein gehre tak kaise ghus jaate hain. Mathematics hazaaron sensor readings ko ek Air Quality Index mein badal deta hai. Aur social sciences sabse mushkil sawaal ka saamna karti hain: kisaanon, shehron aur sarkaaron ko iske baare mein kya karna chahiye?

7/7Kaanoon, kheti ke tareeke aur safar ke choices tay karte hain ki kya badlega.

Fig. 1.8Ek asli problem, knowledge ki kai branches.

Beech mein ek oval hai jis par 'winter smog' likha hai, aur uske chaaron taraf ek-ek karke chhah boxes aate hain, har ek line se oval se juda. Step 1 sirf oval dikhata hai. Step 2 physics jodta hai: hawa mein kan. Step 3 chemistry jodta hai: dhuaan, gases. Step 4 earth science jodta hai: thandi, ruki hawa. Step 5 biology jodta hai: lungs ko nuksaan. Step 6 maths jodta hai: data se AQI. Step 7 social science jodta hai: rules aur faisle.

Aisi problems interdisciplinary (अंतर्विषयक) hoti hain: inhe ek subject ke andar reh kar suljhaya nahi ja sakta. Dengue ko control karne ke liye mosquito ko jaanne wale biologists, safe repellents design karne wale chemists, baarish aur ruke paani ko track karne wale earth scientists, aur cases kahan jhund mein hain yeh map karne wale statisticians chahiye. Subjects ke beech ki deewarein timetables aur degrees ke liye kaam ki hain, lekin nature ne unhe kabhi nahi banaya; humne banaya, taaki jo hum jaante hain use organise kar sakein.

Class 9 aur 10 mein tum ab bhi branches se ek-ek chapter karke miloge, aur tumhari textbook ke Next Level Up boxes ishaara karte hain ki Class 10 ke baad har branch mein kya hai, jab physics, chemistry, biology aur earth science alag subjects ban jaate hain. Inhe ek hi ghar ke kamron ke beech ke darwaaze samjho, alag-alag ghar nahi.

Aage badhne ko taiyaarNCERT Aage Badhne ko Taiyaar · p. 7

Mitti ke matke mein science

Mitti ka bartan, yaani matka (मटका), bina bijli ke Indian garmi mein paani ko thanda rakhta hai. Physics: paani pakki mitti ke chhote-chhote pores se rista hai aur bahari surface se evaporate hota hai, aur evaporation heat ko saath le jaata hai. Chemistry aur earth science: sahi mitti, sahi temperature par pakaayi jaaye, to theek utne hi pores bachte hain. Mausam bhi matter karta hai: sookhi garmi mein matka achha thanda karta hai aur nami wali monsoon hawa mein kam, jab evaporation dheema ho jaata hai. Biology: paani tabhi safe rehta hai jab matke ko ragad kar saaf kiya jaaye taaki microbes na badh sakein. Mathematics: ek ghante mein paani kitne degree thanda hota hai, yeh record karne se tum matkon ko fair tareeke se compare kar sakte ho.

Ruko aur sochoNCERT Ruko aur Socho 3 · p. 6

Ek cheez mein science ka map banao

Tumhe chahiye

kaagaz ki ek sheet
ek pencil

Apne din se ek cheez chuno, jaise cycle, solar panel, refrigerator ya gas stove, ya apne mohalle ki koi puzzle, jaise baarish ke baad machchharon ka badhna ya sookh chuka handpump. Use page ke beech mein ek hub ki tarah banao, aur science ki har us branch tak ek spoke kheencho jise yeh chhoota hai. Phir aise do spokes dhoondho jo ek doosre par depend karte hain, aur likho kaise.

Table 1.7Mere example mein science

Branch	Kaun sa idea juda hai
Physics
Chemistry
Biology
Earth science
Mathematics

Tumhari entries apne aap save hoti hain.

Quick check

2 mein se 1

Science ko physics aur biology jaisi branches mein kyun baanta gaya hai?

Nature khud alag-alag hisson mein bati hui haiKnowledge ko organise karne aur experts taiyaar karne ke liyeHar branch nature ke alag laws follow karti haiBranches ko kabhi ek doosre ke ideas ki zaroorat nahi padti

Answer dekho

Answer (B) Knowledge ko organise karne aur experts taiyaar karne ke liye

Yeh bantwaara humara hai, knowledge ko organise karne aur specialists taiyaar karne ke liye banaya gaya. Nature mein aisi koi seemayein nahi hain, isiliye asli problems ko ek saath kai branches chahiye.

1.9 Science: ek insaani adventure

Atom kisne discover kiya? Iska koi ek jawaab nahi hai, aur yahi to baat hai. Yeh idea do hazaar saal se zyada samay mein kai haathon se guzra (timeline). Praacheen India aur Greece ke vichaarakon ne aise chhote particles ki kalpana ki jinhe kaata nahi ja sakta. England ke John Dalton ne is idea ko aisi theory mein badla jise test kiya ja sake. Phir J. J. Thomson ne electron dhoondha, jisne saabit kiya ki atoms toote ja sakte hain, aur Ernest Rutherford aur Niels Bohr ne picture ko phir se naya roop diya. Har ek ne doosron ke kaam par nirmaan kiya, uska kuch hissa sudhaara aur aage badha diya.

Timeline

Ek idea, kai haath: atom

Praacheen India
Kanada ka paramanu
Matter ko aise chhote, amar particles se bana maana gaya jinhe baanta nahi ja sakta.
c. 400 BCE
Democritus ka atomos
Greece mein 'jo kaata na ja sake' ke liye bana word atom ko uska naam deta hai.
1808
Dalton ki atomic theory
Har element ka apna tarah ka atom hota hai jiska apna mass hota hai; ek testable theory.
1897
Thomson ne electron dhoondha
Atoms mein chhote, negatively charged particles hote hain, isliye unhe toda ja sakta hai.
1911
Rutherford ka nucleus
Atom ka lagbhag saara mass ek chhote, positively charged centre mein hota hai.
1913
Bohr ke shells
Electrons nucleus ke chaaron taraf sirf kuch allowed orbits mein hi chalte hain.

Atom ki kahani aam si hai. Science mein idea relay race ke baton ki tarah aage badhaya jaata hai, aur har dhaavak use gira sakta hai, theek kar sakta hai ya naya roop de sakta hai, phir aage pakda deta hai. Isiliye ek scientist ka sabse kaam ka ek sentence yeh hai: 'Meri galti thi, aur yeh raha evidence.'

Tum mein se zyadatar scientists ke alaawa kuch aur banoge: dukaandaar, nurses, engineers, lawyers, kisaan, artists, aur tum sab voters. Is chapter ki aadatein phir bhi kaam aayengi. 'Tumhe kaise pata?' poochhna tumhe ghaate ke saude ya jhoothe ilaaj se bachata hai. Ek jhatpat estimate das guna zyada bill pakad leta hai. Yeh jaanna ki har model ki limits hoti hain, tumhe har confident forecast par, weather app se lekar opinion poll tak, soch-samajh kar chalne mein madad karta hai.

To page numbers ke do tools ko is book mein saath le chalo (Fig. 1.9): evidence ko gaur se jaanchne ke liye ek lens, aur ek compass jo tumhare sawaalon ko kisi aisi jagah ki taraf rakhe jahan jaana faayde ka ho. Safar ka mazaa lo.

3/3Maqsad ke saath dhyaan se dekhna hi exploration ko scientific banata hai.

Fig. 1.9Aane wale saal ke liye do aadatein.

Step 1 ek magnifying glass dikhata hai jo ek patte ki naso ko bada karke dikhata hai, jis par 'gaur karo' aur 'evidence' likha hai. Step 2 ek compass jodta hai jiski needle north se ghoom kar kone mein bane question mark ki taraf point karti hai, jis par 'direction chuno' aur 'curiosity' likha hai. Step 3 dono ko rakhta hai aur heading 'gaur karo, direction chuno' jodta hai, scientific exploration ki do aadatein.

Quick check

2 mein se 1

Kaun sa statement sabse achhi tarah batata hai ki scientific knowledge kaise badhti hai?

Kai log ek doosre ke kaam ko test karte hain, sudhaarte hain aur uspar aage banate hainEk akela genius har idea ko poora aur final roop mein dhoondh leta haiFamous scientists vote karte hain ki kaun se ideas sach hainFacts ek baar jama kiye jaate hain aur un par kabhi sawaal nahi uthta

Answer dekho

Answer (A) Kai log ek doosre ke kaam ko test karte hain, sudhaarte hain aur uspar aage banate hain

Atom ka idea praacheen vichaarakon se Dalton, Thomson, Rutherford aur Bohr tak pahuncha, aur har ek ne pichhle ko sudhaara aur aage badhaya. Ideas ka faisla evidence se hota hai, votes se ya kisi ek insaan se nahi.

Recap

Summary aur key points

Secondary science sirf yeh nahi poochhti ki hum kya jaante hain, balki yeh bhi ki kaise jaante hain: observe karo, measure karo, patterns dhoondho, unhe maths mein likho, model banao, predict karo, test karo aur revise karo (Section 1.1).
Model kisi asli system ka simplified version hai jo sirf wahi rakhta hai jo sawaal ko chahiye; details chhodna soch-samajh kar kiya gaya choice hai (Section 1.2).
Har model assumptions par tika hota hai; jab simple model kaafi accurate nahi hota, to details wapas jodi jaati hain (Example 1.1).
Science exact matlab wale words (weight, pressure, theory) use karti hai taaki har jagah ke log results ko ek hi tarah samjhein (Section 1.3).
Physical quantities ke agreed symbols aur SI units hote hain; units mila dena bahut bhaari pad sakta hai (Mars orbiter).
Equation is baat ka chhota statement hai ki quantities kaise judi hain, jaise $v = d / t$ ((1.1)).
Law ek pattern batata hai, theory samjhaati hai ki woh kyun hota hai, aur principle ek broad idea hai jo kai situations mein use hota hai (Section 1.4).
Theory achhi tarah tested explanation hai, guess nahi, aur woh sudhaar ke liye khuli rehti hai (Section 1.4).
Predictions laws, theories aur models se nikli soch-samjhi ummeedein hain; testable prediction measurements aur pichhle patterns par tiki hoti hai (Section 1.5).
Jab predictions fail hoti hain, to scientists assumptions, models aur measurements dobara check karte hain, aur faisla evidence karta hai (Neptune, Mercury) (Section 1.6).
Quantity ko hisson mein tod kar lagaaye gaye aur doosre raaste se check kiye gaye rough estimates batate hain ki jawaab sensible hai ya nahi (Section 1.7).
Winter smog jaisi asli problems ko science ki kai branches ek saath chahiye, aur science alag-alag cultures ke bahut se logon ke zariye badhti hai (Section 1.8, Section 1.9).

Quick check: MCQs

1.1 Hum kaise jaante hain, yeh explore karna2 questions
1.2 Models: sirf zaroori cheezein rakhna3 questions
Mathematics: relationships ki bhasha3 questions
1.4 Laws, theories aur principles2 questions
1.5 Predictions: science aage dekhti hai2 questions
1.6 Limits, failures aur self-correction2 questions
1.7 Estimation: rough numbers ke saath sochna3 questions
1.8 Ek duniya, kai branches2 questions
1.9 Science: ek insaani adventure2 questions

Glossary · 11

Key terms (English + Hindi)

assumptionमान्यताmaanyata: Koi baat jise haath ke kaam ke liye kaafi sach maan liya jaaye, jaise 'air resistance negligible hai', taaki model ya calculation banaya ja sake.Chapter mein pehli baar yahan aaya →

estimateअनुमानanumaan: Sensible round numbers se nikaali gayi rough value, jo yeh parakhne ke liye kaafi hai ki jawaab reasonable hai ya nahi.Chapter mein pehli baar yahan aaya →
evidenceसाक्ष्यsaakshya: Observations aur measurements jo kisi idea ko support karte hain ya uske khilaaf jaate hain.Chapter mein pehli baar yahan aaya →

interdisciplinaryअंतर्विषयकantarvishayak: Ek problem ko samajhne ke liye knowledge ki do ya zyada branches, jaise physics aur biology, ka sahaara lena.Chapter mein pehli baar yahan aaya →

modelमॉडलmodel: Kisi asli object, system ya process ka simplified version jo sirf wahi features rakhta hai jo ek khaas sawaal ka jawaab dene ke liye chahiye.Chapter mein pehli baar yahan aaya →

physical quantityभौतिक राशिbhautik raashi: Koi bhi cheez jise naapa ja sake aur unit ke saath number mein likha ja sake, jaise length, mass, time ya temperature.Chapter mein pehli baar yahan aaya →
predictionपूर्वानुमानpoorvaanumaan: Laws, theories, models ya pichhle data par based soch-samjha statement ki kisi aisi situation mein kya hoga jo abhi dekhi nahi gayi.Chapter mein pehli baar yahan aaya →

scientific lawनियमniyam: Ek chhota statement ya equation jo nature ke har baar hone wale kaam ka saar batata hai; yeh batata hai kya hota hai, kyun nahi.Chapter mein pehli baar yahan aaya →
scientific principle: Bahut door tak pahunch wala general idea, jo kai alag situations ke baare mein sochne mein use hota hai, jaise Archimedes' principle.Chapter mein pehli baar yahan aaya →
scientific theoryसिद्धांतsiddhaant: Kuch patterns kyun hote hain, iski achhi tarah tested explanation, jise bahut saare evidence ka support hai aur jo sudhaar ke liye khuli hai.Chapter mein pehli baar yahan aaya →
SI unitSI मात्रकSI maatrak: International System of Units ki ek unit; yeh duniya bhar mein agreed system hai jo metre, kilogram aur second jaisi saat base units par bana hai.Chapter mein pehli baar yahan aaya →

Exploration: Entering the World of Secondary Science (Exploration: Secondary Science ki Duniya mein Kadam): Class 9 Science Chapter 1 Hinglish mein

Is chapter mein aap kya seekhenge

1.1 Hum kaise jaante hain, yeh explore karna

1.2 Models: sirf zaroori cheezein rakhna

1.3 Science ki bhasha: words, symbols aur units

Mathematics: relationships ki bhasha

1.4 Laws, theories aur principles

1.5 Predictions: science aage dekhti hai

1.6 Limits, failures aur self-correction

1.7 Estimation: rough numbers ke saath sochna

1.8 Ek duniya, kai branches

1.9 Science: ek insaani adventure

Summary aur key points

Practice questions answers ke saath (NCERT “Exercises”)

Quick check: MCQs

Key terms (English + Hindi)

Tum chapter ke end tak pahunch gaye