Class 7 Science Ch 5 NCERT Solutions Hinglish mein

Curiosity, Class 7 Science ki kitaab (Reprint 2026-27) ke Chapter 5, Changes Around Us: Physical and Chemical, ke har sawaal ke jawaab: text ke sawaal, Table 5.1 aur 5.2 ke saath Activity 5.1 se 5.8, Science and Society box, Let Us Enhance Our Learning ke dason sawaal aur Exploratory Projects. Page numbers kitaab ke hisaab se hain (pages 57–72). Activities ke jawaab ummeed ke nateeje batate hain; apne observations khud likho. Chhote notes: Chapter 5 ke notes.

Students ke badlaav (page 57)

Ve kis tarah ke badlaavon ki baat kar rahe hain? Baraf ke tukde ka paani banna avastha ka badlaav hai. Kali ka phool banna jeevit paudhe mein badhne ka badlaav hai. Thande paani ki bottle ka garam hona taapmaan ka badlaav hai. Kele mein aur bhoore daag aur tez gandh aana pakna aur phir kharaab hona hai, jismein naye padaarth bante hain. Kuch physical changes hain aur kuch chemical, aur chapter inhe pehchaanna sikhaata hai.

Chapter 5 ka mind map: physical changes, chemical changes, combustion, jalti mombatti mein dono badlaav, ulte ho sakne waale ya na ho sakne waale badlaav, aur dheeme praakritik badlaav — Poora chapter ek page pe

Activity 5.1 aur Table 5.1 (page 58)

Table 5.1: hamaare aas-paas ke kuch badlaav (list ke roop mein):

Baraf ke tukde pighalna: solid baraf liquid paani ban jaati hai.
Sabzi kaatna: size aur aakaar badalte hain.
Paani ubaalna: bulbule bante hain aur paani bhaap banta hai.
Makke se popcorn banana: sakht daane phoolkar naram, safed, bade popcorn bante hain, nayi gandh ke saath.
Kaagaz ka tukda kaatna: size aur aakaar badalte hain.
Paani mein chukandar ka ras milaana: rang phailne se paani laal se gulaabi ho jaata hai.
Lakdi jalaana: lakdi raakh aur dhuaan banti hai, garmi aur roshni ke saath.
Geele kapde sukhaana: paani vaashp banke ud jaata hai aur kapde sookh jaate hain.
Aate ki chhoti goliyan banaana: aate ka aakaar badalta hai.
Aate ki goliyon se chapati belna: goliyan chapti aur gol ho jaati hain, yaani aakaar aur size badalte hain.
Koi aur: jaise doodh se dahi banne mein swaad, gandh aur gaadhapan badalte hain.

Aas-paas ke aur badlaav: pattiyon ka peela padna, mombatti jalna, ice cream pighalna, bread ka sikna, paani ke gadde ka sookhna, lohe ke gate mein jang lagna aur beejon ka ankurit hona.

Activity 5.2 (page 59)

A. Kaagaz ki cheezein: kholne par wahi kaagaz waapas milta hai, bas tahon ke nishaan ke saath.
B. Gubbaara: hawa nikalne par bina phula gubbaara waapas mil jaata hai. Phule gubbaare mein pin chubhaane par vo phatkar rubber ke tukdon mein bikhar jaata hai, aur bina phula gubbaara waapas nahi milta.
C. Chalk: powder se chalk ka tukda waapas nahi banaaya ja sakta.

Samaanta: A, B aur C mein padaarth, kaagaz, rubber aur chalk, wahi rehte hain; sirf unka aakaar ya size badalta hai. Koi naya padaarth nahi banta, isliye ye sab physical changes hain.

Kaagaz modna, gubbaara phulaana, chalk peesna, aur baraf, paani aur bhaap: har baar wahi padaarth — Wahi padaarth, naya roop

Activity 5.3 (page 60)

Kya koi badlaav dikha? Nal ke paani (A) mein phoonk se sirf bulbule bante hain; paani waisa hi dikhta hai. Lime water (B) mein bhi bulbule bante hain, par lime water doodhiya ho jaata hai, aur kuch der baad neeche safed solid baith jaata hai. Saans ki carbon dioxide se naya padaarth, calcium carbonate, bana, isliye ye chemical change hai: calcium hydroxide (lime water) + carbon dioxide → calcium carbonate + paani.

Nal ke paani mein phoonk se sirf bulbule, jabki lime water doodhiya hota hai aur safed solid baithta hai — Paani aur lime water mein phoonk

Activity 5.4 (page 61)

Sirka ya nimbu ka ras aur baking soda: jhaag ki aawaaz aati hai aur gas ke bulbule dikhte hain.
Gas ko taaze lime water se guzaarna: lime water doodhiya hota hai, isliye gas carbon dioxide hai. Naya padaarth bana, to ye chemical change hai.
Baking soda aur saada paani: bulbule nahi bante. Baking soda sirf ghulta hai, jo physical change hai.

Ek tube mein sirka aur baking soda ka jhaag, aur doosri mein gas se lime water doodhiya — Sirka aur baking soda

Jang aur magnesium jalaana (page 62)

Magnesium ribbon jalaana physical change hai ya chemical? Chemical. Naya padaarth, magnesium oxide, ek safed powder, banta hai, aur garmi aur roshni nikalti hai: magnesium + oxygen → magnesium oxide + garmi + roshni. Jang lagna bhi chemical hai, kyunki jang (iron oxide) naya padaarth hai.

Activity 5.5 (pages 62–63)

Dono mombattiyon ki lau ka kya hota hai? Khuli mombatti jalti rehti hai, jabki glass ke tumbler se dhaki mombatti kuch der baad bujh jaati hai, kyunki use lagaataar hawa nahi milti, aur jalne ko oxygen chahiye. Tumbler ke neeche carbon dioxide ki jaanch kaise karein? Petri dish mein thoda lime water daalo: vo doodhiya hota hai, jo dikhata hai ki wax ke carbon aur hawa ki oxygen se carbon dioxide bani.

Khuli mombatti jalti rehti hai; glass se dhaki mombatti bujh jaati hai, aur uski dish ka lime water doodhiya hota hai — Kya lau ko hawa chahiye?

Science and Society (page 63)

Kisi ke kapdon ki aag kaise bujhaayein? Us insaan ke chaaron or kambal ya kapda lapet do. Isse hawa ruk jaati hai, aur aag bujh jaati hai. Synthetic kambal ya kapda kabhi mat lo, vo pighalkar twacha se chipak sakta hai.

Activity 5.6 (page 64)

Kya jalna shuru karne ke liye aag chahiye? Nahi. Jalti maachis kaagaz ko jaldi jala deti hai, par magnifying glass se chhote chamakdaar dhabbe mein ikatthi dhoop bhi kaagaz se pehle dhuaan aur phir aag nikalwaati hai, bina kisi lau ke. Kaagaz tab jalta hai jab apne ignition temperature tak pahunche, yaani vo sabse kam taapmaan jis par vo aag pakadta hai. Maachis ki lau pehle se us taapmaan se zyaada garam hai, isliye kaagaz lagbhag turant jalta hai. To combustion ko fuel, oxygen, aur ignition temperature tak pahunchaane waali garmi chahiye: fire triangle.

Magnifying glass se ikatthi dhoop kaagaz ko jalne tak garam karti hai; taapmaan ki scale pe kaagaz ka ignition temperature — Ignition temperature

Activity 5.7 (page 65)

Mombatti jalne par kya badlaav hote hain? Har student kuch had tak sahi hai. Lau ke paas wax pighalta hai; pighla wax batti pe chadhkar garmi se vaashp banta hai; neeche behta wax alag-alag aakaaron mein jam jaata hai. Ye physical changes hain. Wax ki vaashp jalkar lau banaati hai aur naye padaarth banaati hai, jo chemical change hai. Isliye jalti mombatti mein physical aur chemical badlaav saath-saath hote hain.

Jalti mombatti ke physical changes, pighalna, batti pe chadhna, vaashp banna aur jamna, aur uska chemical change, wax ki vaashp ka jalna — Mombatti jalne par kya hota hai?

Activity 5.8 aur Table 5.2 (page 66)

Table 5.2: kya badlaav ulta ho sakta hai? (list ke roop mein):

Baraf ke tukde pighalna: Haan, paani phir jamaaya ja sakta hai
Sabzi kaatna: Nahi, tukde waapas nahi judte
Paani ubaalna: Haan, bhaap ko phir paani banaaya ja sakta hai
Makke se popcorn banana: Nahi
Kaagaz ka tukda kaatna: Nahi
Paani mein chukandar ka ras: sirf kuch had tak; paani udaane par rang waala hissa bach jaata hai
Lakdi jalaana: Nahi
Geele kapde sukhaana: Haan
Aate ki chhoti goliyan banaana: Haan
Goliyon se chapati belna (pakaane se pehle): Haan
Kaagaz modkar cheezein banaana: Haan
Lohe mein jang lagna: Nahi

Ulte ho sakne waale badlaav, jaise baraf pighalna, paani ubaalna aur kaagaz modna, aur na ho sakne waale, jaise sabzi kaatna, popcorn banana aur jang — Kya badlaav ulta ho sakta hai?

Chahe gaye badlaav (page 66)

Aas-paas ke aur chahe gaye badlaav: beejon ka ankurit hona, yeast se aate ka phoolna, daal-chaawal pakna, ganne ke ras se gud banna, bhatti mein mitti ke bartan pakna, aur hamaare shareer mein khaana pachna.

Let Us Enhance Our Learning (pages 69–72)

1. (c) (i) aur (iii). Physical change mein avastha badal bhi sakti hai aur nahi bhi, aur koi naya padaarth nahi banta. Alag properties waala padaarth banna, (ii), aur chemical reaction hona, (iv), chemical change ki baatein hain.

2. Kya ye badlaav ulte ho sakte hain?

(i) Kapde ko silkar shirt banaana: zyaadatar ulta ho sakta hai; silaai udhedkar tukde alag kiye ja sakte hain, par kapde ke kate hisse waise hi rehte hain. Ise “pakka nahi” bhi likh sakte ho.
(ii) Seedhi rassi ko ainthna: ulta ho sakta hai; ainthan khol do.
(iii) Ghol se idli banaana: ulta nahi ho sakta; bhaap mein ghol pak jaata hai.
(iv) Paani mein cheeni gholna: ulta ho sakta hai; paani udaakar cheeni waapas pao.
(v) Kuein se paani nikaalna: ulta ho sakta hai; paani waapas daala ja sakta hai.
(vi) Phalon ka pakna: ulta nahi ho sakta.
(vii) Khule bartan mein paani ubaalna: pakka nahi. Bhaap ko phir paani banaaya ja sakta hai, par khule bartan se vo hawa mein ud jaati hai, isliye wahi paani aasaani se waapas nahi milta.
(viii) Chatai lapetna: ulta ho sakta hai; phaila do.
(ix) Gehun ko pees kar aata banaana: ulta nahi ho sakta.
(x) Chattaanon se mitti banna: ulta nahi ho sakta.

Kuch ke baare mein pakka kyun nahi? Kyunki badlaav ka sirf ek hissa waapas ho sakta hai, jaise silaai mein, ya siddhaant mein waapas ho sakta hai par asal mein aasaani se nahi, jaise khule bartan se udti bhaap.

3. Sahi ya galat.

(i) Sahi. Wax ko pehle pighalna aur phir vaashp banna padta hai; jalti wax ki vaashp hai.
(ii) Galat. Paani ki vaashp ko condense karna avastha ka badlaav hai, isliye sahi vaakya: condense karke paani ki vaashp ikattha karna physical change hai.
(iii) Sahi. Bacteria aur fungi pattiyon ko naye padaarthon mein todte hain, isliye compost banna chemical change hai.
(iv) Sahi. Carbon dioxide, ek naya padaarth, banta hai.

4. Khaali jagah bharo.

(i) Bhoori parat jang lagne ki wajah se hai, aur ye chemical change hai.
(ii) Rumaal modna physical change hai aur ise ulta kiya ja sakta hai.
(iii) Jis chemical prakriya mein padaarth oxygen ke saath reaction karke garmi deta hai, use combustion kehte hain, aur ye chemical change hai.
(iv) Hawa mein jalne par magnesium magnesium oxide banaata hai. Bana padaarth basic hai. Magnesium ka jalna chemical change hai.

5. Paani se baraf aur paani se bhaap. Dono physical changes hain. Sirf avastha badalti hai, liquid se solid ya liquid se gas; baraf, paani aur bhaap sab ek hi padaarth, paani, hain, aur koi naya padaarth nahi banta. Dono ulte ho sakte hain: baraf pighalkar phir paani banti hai, aur bhaap thandi hokar phir paani.

6. Doodh ka phatna ya dahi banna physical hai ya chemical? Chemical. Doodh dahi ban jaata hai, jiska swaad, gandh aur gaadhapan naya hai, kyunki naye padaarth bante hain, aur dahi waapas doodh nahi ban sakta.

7. Chattaanon se mitti banna: physical ya chemical? Dono. Hawa, baarish, garmi-thand, jadein aur jamta paani chattaanon ko chhote tukdon mein todte aur le jaate hain: ye physical changes hain (weathering aur erosion). Paani aur hawa kuch chattaanon ke saath reaction karke unki banaawat bhi badalte hain, jaise basalt ke lohe se laal iron oxide banna: ye chemical change hai. Dono milkar dheere-dheere mitti banaate hain.

Garmi-thand, jadon aur baraf se physical weathering, aur basalt ko laal karne waali chemical weathering, jo chattaanon ko sediments aur phir mitti mein badalti hai — Weathering: chattaan se mitti

8. Eco-friendly Prithvi. Sabzi kaatna, aaloo chheelna aur phal kaatna: physical changes. Beej, phal aur chhilke mitti ke bartan mein ikattha karna: physical change. Bacteria aur fungi se kachre ka sadkar compost banna: chemical change. Beejon ka ankurit hona, badhna aur phoolon mein khilna: chemical change. Apni pasand ka shirshak, jaise: Chhilkon se Phoolon Tak (From Peels to Petals).

Prithvi ki kahaani kadam-dar-kadam: kaatna aur ikattha karna physical changes, compost aur paudhon ka badhna chemical changes — Sawaal 8

9. Venn diagram.

A (physical changes): kaagaz phaadna, baraf pighalna, kapde modna.
B (chemical changes): jang lagna, doodh phatna, phalon ka pakna, magnesium jalaana, baking soda aur sirka milaana.
C (dono): mombatti jalne ki prakriya.

Venn diagram: A mein physical changes, B mein chemical changes, aur beech ke C mein mombatti jalna — Sawaal 9

10. Kis lime water ne doodhiya rang liya? (a), sirka aur baking soda, aur (d), nimbu ka ras aur baking soda, mein. Baking soda acid, yaani sirke ya nimbu ke ras, ke saath reaction karke carbon dioxide banaata hai, jo lime water ko doodhiya karti hai. (b) mein nimbu ka ras aur sirka dono acid hain aur carbon dioxide nahi banti; (c) mein sirka aur namak bhi carbon dioxide nahi dete, isliye lime water saaf rehta hai.

Fig. 5.11 ke chaar set-up: sirka aur baking soda, aur nimbu ka ras aur baking soda se lime water doodhiya, baaki do mein saaf — Sawaal 10

Exploratory Projects (pages 71–72)

Adrishya syaahi. Nimbu ka ras sookhte samay uska paani ud jaata hai aur sandesh gaayab ho jaata hai; ye physical change hai. Garam karne par sookha ras gehra bhoora ho jaata hai, kyunki garmi use naye padaarthon mein badal deti hai, jo chemical change hai. Bhoora hona ulta nahi ho sakta. (Ye sirf kisi bade ke saath karo.)

Landslide aur chattaanon ka erosion kam karna. Dhalaanon pe ped, jhaadiyan aur ghaas lagao taaki jadein mitti ko pakdein; sadkon aur imaaraton ke liye pahaadon ko seedha mat kaato; retaining walls aur sahi naaliyan banao taaki baarish ka paani dhalaanon ko bhigokar dheela na kare; bina yojana ki mining aur khudaai roko; pahaadon pe seedhidaar kheti karo; aur tez baarish mein chetaavaniyon pe dhyaan do.

Rasoi ke ulte ho sakne waale badlaav. Makkhan ya ghee pighalna, paani jamaakar baraf banaana, cheeni ya namak ghulna, dhakkan pe bhaap ka paani banna, aur aata belna. Ye physical changes hain. Chaawal pakaana, anda ubaalna aur bread sekna ulte nahi ho sakte, kyunki ye chemical changes hain.

Yeast kaise kaam karta hai. Cheeni ke ghol aur yeast waali bottle pe laga gubbaara dheere-dheere gas se bharta hai. Taaze lime water ke saath hilaane par gas use doodhiya karti hai, isliye vo carbon dioxide hai: yeast cheeni ko todkar carbon dioxide chhodta hai. Bread mein ye gas ke bulbule aate mein phans jaate hain aur use phoola aur naram banaate hain. Cheeni ka ghulna aur gubbaare ka khinchna physical changes hain; yeast ka cheeni todna aur lime water ka doodhiya hona chemical changes hain.

Cheeni ke ghol aur yeast waali bottle pe gubbaara gas se bharta hai jo lime water ko doodhiya karti hai; physical aur chemical changes ki list — Yeast, cheeni aur gubbaara

Girgit ka rang badalna. Haan, ye badlaav ulta ho sakta hai: girgit baar-baar rang badalta hai, kyunki uski twacha ki khaas koshikaayein roshni ko alag tarah lautaati hain. Ye ek jeevit jaanwar ka badlaav hai, jang jaisa naya padaarth nahi.

Chhote notes aur practice topic pages pe hain: physical aur chemical changes, combustion kya hai aur reversible aur irreversible changes kya hain.

NCERT Solutions Class 7 Science Chapter 5: Changes Around Us: Physical and Chemical (Hinglish)