Class 7 Science · Chapter 12
Short answer: Chapter 12 'Earth, Moon and the Sun' Class 7 Science Curiosity book ka chapter hai jisme Earth-Moon-Sun ke shapes, sizes, motions (rotation aur revolution), Moon phases, day-night cycle, seasons, aur solar-lunar eclipses cover hote hain — sab kuch relative position aur reflected light ke concept par based hai.
Chapter 12 'Earth, Moon and the Sun' NCERT Class 7 Science ki Curiosity book ka aakhri chapter hai, aur ye chapter humein humari apni solar neighbourhood — Earth, uska satellite Moon, aur Sun — ke beech ke relationships samajhne ke liye lekar jaata hai. Ye chapter Class 7 ke liye basic Astronomy aur Earth Science ki neev hai — jo aage Class 8-10 me Universe, gravitation, aur planetary motion jaise topics samajhne me kaam aayega. Is chapter me hum sabse pehle Sun, Earth aur Moon ke shapes, sizes aur unki relative positions ka comparison karte hain. Phir hum samajhte hain ki Earth apni axis par rotate karke day aur night kaise create karti hai, aur Sun ke chaaron taraf revolve karke seasons kaise badalti hai. Sabse interesting hissa hai Moon ki phases — Purnima se Amavasya tak ka cycle — jo Moon ki apni light na hone aur sirf Sun ki reflected light dikhane ki wajah se hota hai. Aakhir me hum solar aur lunar eclipses ka concept samajhte hain, jo tab hote hain jab Sun, Earth aur Moon ek particular alignment me aate hain. Ye chapter memorization se zyada visualization aur logical reasoning maangta hai — isliye diagrams aur models (jaise torch-ball activity) se samajhna sabse effective tareeka hai.
Chapter 12 Summary — 5 Minute Revision
Chapter 12 'Earth, Moon and the Sun' ka core summary:
- Sun sabse bada hai, phir Earth, phir Moon — size order yaad rakhein: Sun >>> Earth > Moon.
- Moon khud light produce nahi karta — jo chandni hum dekhte hain wo Sun ki reflected light hai.
- Earth apni axis par rotate karke day-night (~24 hours) banati hai, aur Sun ke chaaron taraf revolve karke year (~365.25 days) complete karti hai.
- Earth ki axial tilt (~23.5°) hi seasons badalne ka main reason hai, na ki Sun se distance.
- Moon ki Earth ke chaaron taraf revolution (~29.5 din) hi Moon phases — Amavasya se Purnima tak — banati hai.
- Solar eclipse: Sun-Moon-Earth alignment, Amavasya ke din. Lunar eclipse: Sun-Earth-Moon alignment, Purnima ke din.
- Eclipses har amavasya/purnima pe nahi hote kyunki Moon ki orbit Earth-Sun plane se ~5° tilted hai.
Ye chapter Curiosity book (2026-27 rationalised session, 12 chapters) ka hissa hai. Related conceptual foundation ke liye Class 7 Science ke doosre chapters bhi useful hain — jaise Light, Shadows and Reflections (jisme reflection ke basic principles cover hote hain jo Moon ki reflected light samajhne me help karte hain), Measurement of Time and Motion (jisme motion aur periodic events measure karna sikhaya jaata hai — Earth-Moon motion se directly related), aur Heat Transfer in Nature (jisme Sun se Earth tak energy transfer discuss hota hai). Agar aap poore Curiosity book ka structure dekhna chahte hain, to class 7 science curiosity book chapter wise pdf se poora syllabus reference kar sakte hain — lekin dhyan rahe ki purani 13-chapter book ke chapters jaise Nutrition in Plants, Nutrition in Animals, ya standalone Electric Current chapter is naye 2026-27 rationalised structure me nahi hain.
In-Text Questions — Solutions
Page ke beech me diya gaya question: Kya Moon apni khud ki light produce karta hai?
Nahi. Moon opaque hai aur khud light produce nahi karta. Raat ko hume jo chandni (moonlight) dikhti hai wo asal me Sun ki light hai jo Moon ki surface se reflect hokar Earth tak pahunchti hai. Yehi wajah hai ki jab Moon ka lit hua hissa humari taraf face nahi karta, to wo dark dikhta hai (jaise Amavasya ke din).
Activity-based in-text question: Ek torch aur ek gend (ball) leke Earth-Moon-Sun ka model banayiye — kaise pata chalega ki phases kaise banti hain?
Is activity me torch ko Sun, ek badi ball ko Earth aur ek chhoti ball ko Moon maan lete hain. Torch ko fixed rakhkar chhoti ball (Moon) ko badi ball (Earth) ke chaaron taraf ghumaya jata hai. Jaise-jaise Moon apni position badalta hai, uska jo hissa torch (Sun) ki taraf face karta hai wo lit dikhega aur baaki hissa dark. Observer (badi ball ke paas khada) is lit hisse ka alag-alag view dekhega — yehi phases ka simulation hai. Ye activity practically dikhati hai ki phases sirf relative position ki wajah se banti hain, na ki Moon ke shape badalne se.
Exercise Questions — Solutions (Q1–Q2)
Q1. Purnima ke din chand poora gol kyun dikhta hai, jabki amavasya ke din bilkul nahi dikhta? Karan samjhaiye.
Answer: Chand khud light produce nahi karta — hum jo bhi chandni dekhte hain, wo actually Sun ki reflected light hai jo Moon ki surface se bounce hokar Earth tak aati hai.
Jab Earth, Moon aur Sun is tarah align hote hain ki poora sunlit hemisphere of Moon humari taraf face karta hai — us din poora gol chand (Full Moon / Purnima) dikhta hai.
Jab Moon, Earth aur Sun ke beech me aa jata hai (ya us position ke kareeb), to Moon ka jo hemisphere humari taraf hai wo dark (unlit) hota hai — isliye Amavasya (New Moon) ke din chand practically invisible ho jata hai. Ye alternating pattern Moon ki Earth ke chaaron taraf revolution ki wajah se hota hai, jisme ~29.5 din lagte hain.
Q2. Solar eclipse aur lunar eclipse me teeno paltu bodies (Sun, Earth, Moon) ka relative arrangement bataiye, aur explain kijiye ki dono eclipses saal me sirf kabhi-kabhi hi kyun hote hain, har amavasya/purnima pe kyun nahi.
Answer:
Solar eclipse: Arrangement hota hai Sun — Moon — Earth, yaani Moon beech me aa jata hai aur Sun ki light ko kuch der ke liye block kar deta hai, jisse Earth ke kuch hisson par Moon ka shadow padta hai. Ye sirf Amavasya (New Moon) ke din hi possible hai.
Lunar eclipse: Arrangement hota hai Sun — Earth — Moon, yaani Earth beech me aa jati hai aur apna shadow Moon par daalti hai. Ye sirf Purnima (Full Moon) ke din hi possible hai.
Har amavasya/purnima pe eclipse kyun nahi hota: Moon ki orbit around Earth, Earth ki orbit around Sun ke plane se thoda sa (~5°) tilted hai. Isliye zyadatar amavasya/purnima ke din teeno bodies perfectly ek seedhi line me nahi aate — Moon thoda upar ya neeche se guzar jata hai. Sirf jab New Moon ya Full Moon exactly us line ke paas (nodes ke kareeb) hota hai, tabhi eclipse hota hai — isliye ye saal me limited baar hi hote hain.
Important Equations — Ek Nazar Me
| Concept | Rule / Fact | Approx. Value |
|---|---|---|
| Earth ki rotation period (day-night) | Apni axis par ek chakkar | ~24 hours |
| Earth ki revolution period (year) | Sun ke chaaron taraf ek chakkar | ~365.25 days |
| Moon ki revolution period (phases cycle) | Earth ke chaaron taraf ek chakkar (New Moon to New Moon) | ~29.5 days |
| Earth ki axial tilt | Seasons ka main karan | ~23.5° |
| Moon orbit ka tilt (Earth-Sun plane se) | Har amavasya/purnima pe eclipse na hone ka karan | ~5° |
| Solar eclipse condition | Sun — Moon — Earth alignment, Amavasya ke din | — |
| Lunar eclipse condition | Sun — Earth — Moon alignment, Purnima ke din | — |
| Size order | Sun >>> Earth > Moon | — |
↔ Table ko side me swipe karein
Common Mistakes — Yahan Marks Kat te Hain
- Students aksar sochte hain ki Moon khud light produce karta hai — yaad rakhein, Moon sirf Sun ki reflected light dikhata hai, wo khud luminous nahi hai.
- Amavasya ka matlab galat samjha jaata hai ki 'Moon gayab ho gaya' — actually Moon wahin hai, bas uska dark (unlit) hissa humari taraf face kar raha hota hai.
- Seasons ko Earth ki Sun se distance change hone ki wajah se badalna maan lena galat hai — asli karan Earth ki axial tilt (~23.5°) hai, distance nahi.
- Solar aur lunar eclipse ke order/position ko ulta yaad karna — yaad rakhein: Solar eclipse me Moon beech me hota hai (Sun-Moon-Earth), lunar eclipse me Earth beech me hoti hai (Sun-Earth-Moon).
- Ye sochna ki eclipse har Amavasya/Purnima pe hota hai — actually Moon ki orbit tilted hone ki wajah se eclipse sirf kabhi-kabhi hota hai, jab alignment exact ho.
- Day-night cycle ko Earth ki Sun ke chaaron taraf revolution se confuse karna — day-night Earth ki apni axis par rotation se hoti hai, revolution se saal (year) aur seasons decide hote hain.
Board-Style Important Questions
- NCERT Class 7 Science textbook ke andar-diye exercise questions (chapter-end) — official past-paper years/codes is book ke liye publicly documented nahi hain kyunki ye ek naya rationalised chapter hai.
- School-level unit tests/periodic assessments me is topic se diagram-based questions (Moon phases label karna) frequently poochhe jaate hain — specific paper codes verify nahi ho paaye.
- Olympiad-level (NSO/IMO jaisi competitive exams) me Earth-Moon-Sun motion se conceptual MCQs aana common hai, lekin specific year-wise data yahan claim nahi kiya ja sakta bina source verify kiye.
- Recommend: apne school ke latest periodic test paper ya sample paper se hi exact past question pattern cross-check karein, kyunki ye chapter Curiosity book (naya syllabus) ka hissa hai aur historical CBSE board-level PYQ data isके liye abhi limited hai.
Aksar Poochhe Jaane Wale Sawaal
Class 7 Science Curiosity book me Chapter 12 'Earth, Moon and the Sun' me kya-kya topics cover hote hain?
Is chapter me Sun, Earth aur Moon ke beech ke motions, unke shapes aur sizes ka comparison, Moon ki phases (Purnima se Amavasya tak), day-night cycle ka reason, seasons kyun badalte hain, aur solar-lunar eclipses jaise concepts cover hote hain. Ye chapter basically Earth Science aur basic Astronomy ka introduction hai jo aage ke classes me detailed planetary motion samajhne ki neev banata hai.
Moon ki phases kyun hoti hain — simple language me samjhaiye?
Moon khud light produce nahi karta, wo sirf Sun ki light reflect karta hai. Jaise-jaise Moon Earth ke chaaron taraf revolve karta hai (~29.5 din me ek chakkar), humein uska alag-alag lit-up hissa dikhta hai — kabhi poora (Purnima), kabhi aadha (First/Last Quarter), kabhi bilkul nahi (Amavasya). Yehi cyclical change hi Moon phases kehlata hai.
Solar eclipse aur lunar eclipse me kya difference hai?
Solar eclipse tab hota hai jab Moon, Sun aur Earth ke beech me aa jata hai aur Sun ki light block karta hai (sirf din me, Amavasya ke din possible). Lunar eclipse tab hota hai jab Earth, Sun aur Moon ke beech me aa jati hai aur apna shadow Moon par daalti hai (raat me, sirf Purnima ke din possible).
Class 7 Science ki NCERT Curiosity book me total kitne chapters hain aur ye syllabus 2026-27 session ke liye rationalised hai kya?
2026-27 session ke liye current rationalised NCERT Class 7 Science book 'Curiosity' hai jisme total 12 chapters hain — pehle wali 13-chapter book se reduce karke banayi gayi hai. Kai purani topics jaise Nutrition in Plants, Nutrition in Animals, alag se Acids-Bases-Salts chapter, Respiration, Reproduction in Plants, aur Electric Current jaise standalone chapters ab is naye structure me nahi hain ya merge/reshape ho gaye hain — isliye purane aggregator listings se match karte waqt dhyan rakhein.
Kya Earth, Moon aur Sun teeno same size ke hain?
Bilkul nahi — Sun sabse bada hai, jiske andar lakhon Earth samaa sakti hain. Earth, Moon se kaafi bada hai (Moon ka diameter roughly Earth ka ~1/4 hai). Size ke hisaab se order hai: Sun >>> Earth > Moon. Lekin Moon humein Sun jitna bada isliye dikhta hai kyunki wo Earth ke bahut kareeb hai, jabki Sun bahut door hai.
Day aur night kyun hote hain, aur seasons kyun badalte hain?
Day-night Earth ki apni axis par rotation (24 ghante me ek chakkar) ki wajah se hota hai — jo hissa Sun ki taraf face karta hai wahan din hota hai, jo hissa opposite side hota hai wahan raat. Seasons Earth ki tilted axis (~23.5°) aur Sun ke chaaron taraf revolution ki wajah se badalte hain — jab koi hemisphere Sun ki taraf zyada tilt hota hai, wahan summer hoti hai, aur jab door tilt hota hai, wahan winter.
Class 7 Science — Saare Chapters
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