Rail ki Patriyon mein Gap Kyun Hota Hai?
Garmi mein loha thoda “lamba” ho jaata hai, isliye patri ko failne ki jagah chahiye 🚆
📖 Kahani: Train ki “Dhadak-Dhadak” ka Raaz
Diwali ki chhuttiyon mein Golu, Priya aur Rohan train se naani ke ghar ja rahe the. Khidki ke paas baithe Golu ne dhyaan diya: “Dhadak-dhadak… dhadak-dhadak…” Har kuch second mein ek jaisi awaaz.
Station pe train ruki toh Priya ne platform se (peeli line ke peechhe khade ho kar) patri ki taraf dekha: “Arre, dekho! Do patriyon ke beech chhota-sa gap chhoda hua hai. Kya mazdoor bhaiya jodna bhool gaye?”
Rohan bola: “Shayad lamba loha milta hi nahi hoga, isliye tukde jode hain.” Golu ne sir hilaaya: “Par phir gap kyun? Chipka ke kyun nahi joda?”
Teeno soch mein pad gaye. Yeh gap galti hai ya kisi ka “dimaag”? Chalo, aaj iska asli “kyun” dhoondhte hain. 🔍
✅ Seedha Jawab
Garam hone pe loha (steel) thoda lamba ho jaata hai — ise prasaar (expansion) kehte hain. Garmi ki dhoop mein patri tapti hai aur failti hai. Agar failne ki jagah na ho, toh patriyan ek doosre ko dhakel ke tedhi (mud) sakti hain aur train patri se utar sakti hai. Isliye joints pe thoda gap chhoda jaata hai.
🤔 Kyun? Step-by-Step
Patri bilkul thos dikhti hai, par andar se woh crore-crore chhote kanon (particles) se bani hai, jo apni-apni jagah pe jude hain.
Kyun yeh zaroori hai? Kyunki failna ya sikudna asal mein in kanon ke beech ki doori ka khel hai. Kan samjhe, toh poora raaz samjha.
Thos ke kan apni jagah se hilte toh nahi, par apni jagah pe hi aage-peeche thartharaate (vibrate) rehte hain.
Kyun? Kyunki har kan ke paas thodi urja (energy) hoti hai. Jitni zyada urja, utna zyada kaanpna.
Dopahar ki dhoop patri ko garam karti hai. Garmi milte hi kan aur zor se, aur door tak kaanpne lagte hain.
Kyun? Garmi ek tarah ki urja hi hai. Dhoop ki urja patri ke kanon mein chali jaati hai.
Socho school assembly ki line. Sab seedhe khade hon toh line chhoti. Ab sab haath hilaate hue “PT” karne lagein, toh har bachcha thodi zyada jagah lega aur poori line lambi ho jaayegi.
Kyun? Har kan ko kaanpne ke liye thodi zyada jagah chahiye, isliye kanon ke beech ki doori thodi badh jaati hai. Kan khud bade nahi hote!
Ek kan ki doori bahut-bahut kam badhti hai. Par ek patri mein karodon kan ek line mein hain, toh sabki chhoti badhat jud ke kuch millimetre ban jaati hai. Ek 13 metre lambi steel ki patri ka taapmaan 40°C badhe, toh woh lagbhag 6 mm lambi ho jaati hai.
Kyun itna? Steel ka har 1 metre, har 1°C garmi pe lagbhag 0.012 mm badhta hai. 13 × 40 × 0.012 ≈ 6.2 mm.
Loha failna “chahta” hai. Agar aage doosri patri chipki hai aur jagah nahi, toh woh rukta nahi; woh bagal mein mud jaata hai. Ise patri ka tedha hona (buckling) kehte hain. Isliye joint pe kuch millimetre ka chhota gap chhoda jaata hai, taaki garmi mein patri aaraam se usme fail sake.
Kyun mudti hai? Kyunki lambi patli cheez ko dono taraf se dabao toh woh seedhi rehne ki jagah bagal mein jhuk jaati hai — jaise do haathon ke beech dabaya hua scale.
Thand mein kan kam kaanpte hain, paas-paas aa jaate hain, aur patri thodi sikud jaati hai. Isliye sardi mein gap thoda bada, aur garmi mein chhota dikhta hai.
Kyun? Kam urja = kam kaanpna = kam jagah.
Ek line mein: Garmi → kan zyada kaanpte → thodi zyada jagah → patri lambi → gap mein fail jaati hai, tedhi nahi hoti. 🚆
🖼️ Picture se Samjho
📕 Textbook Yeh Nahi Batata
Aaj kal kai nayi aur badi railway lines pe aapko har 13 metre pe gap nahi milega! Wahan patriyon ko weld karke (pighla ke jod ke) sau-sau metre ya kilometre-bhar lambi ek patri bana di jaati hai. Isliye un lines pe “dhadak-dhadak” bhi kam sunai deta hai.
Toh failna kahan jaata hai? In patriyon ko bhaari concrete ke sleepers aur mazboot clips se itna kas ke pakda jaata hai ki woh lambai mein fail hi na sakein. Failne ka zor patri ke andar “dabav” ban ke reh jaata hai. Inhe ek theek-thaak (na bahut thande, na bahut garam) taapmaan pe bichhaya jaata hai, aur in lambi patriyon ke dono siron pe ek khaas tirchha jod hota hai jo thoda khisak sakta hai. Phir bhi bahut tez garmi mein railway ke log patriyon pe khaas nazar rakhte hain. Matlab science wahi hai, bas jugaad naya hai! 😎
🚫 Log Aisa Sochte Hain… Lekin
✅ Lekin: kan ka size wahi rehta hai. Badhti hai sirf kanon ke beech ki doori, kyunki woh zyada kaanpte hain.
✅ Lekin: loha bhi failta hai, bas thoda-sa. Aur yeh thoda-sa failna bhi itne bade zor se hota hai ki moti patri ko mod de.
✅ Lekin: asli wajah failne ki jagah dena hai. Aaj toh kilometre-bhar lambi welded patriyan bhi banti hain, par unhe kas ke pakadna padta hai.
✅ Lekin: gap sirf kuch millimetre ka hota hai aur dono patriyan steel ki plates (fishplates) se bolt karke judi hoti hain. Pahiya aaraam se upar se nikal jaata hai, bas “dhadak” ki awaaz aati hai.
🏠 Ghar ka Mini Experiment: “Garmi se Failne wala Gubbara”
Patri ka failna aankh se dikhna mushkil hai (sirf millimetre!). Par hawa garmi mein bahut zyada failti hai. Isse hum “garmi = failna” wala niyam apni aankhon se dekh sakte hain.
Saamaan: ek khaali plastic ki chhoti bottle (dhakkan hata ke), ek gubbara (balloon), do bade bartan/bowl, nal ka gungunaa (halka garam) paani, aur thanda paani.
Kya dikhega aur kyun: Gungune paani mein gubbara thoda khada / phoola ho jaayega, kyunki bottle ki hawa garam hui, uske kan tez bhaagne lage aur zyada jagah lene lage. Thande paani mein hawa sikud jaati hai aur gubbara wapas latak jaata hai. Patri ke steel ke saath bhi bilkul yahi hota hai, bas bahut-bahut kam maatra mein.
🌍 Real Life Mein
- Pul (bridges) ke jod: flyover ya pul pe gaadi chalte hue kabhi “khat-khat” mehsoos hua? Wahan lohe ki daantedaar patti ka jod hota hai (expansion joint), taaki pul garmi mein fail sake.
- Bijli ke taar: khambon ke beech taar thode dheele latka ke baandhe jaate hain. Sardi mein taar sikudte hain; agar garmi mein ekdum tight baandhe hote, toh sardi mein toot sakte the.
- Cement ki sadak aur farsh: cement ki sadakon mein thodi-thodi doori pe kati hui lines dikhti hain. Yeh bhi failne-sikudne ki jagah hai, warna sadak mein daraar aa jaati.
- Thermometer: usme bhara drav garmi mein failta hai aur nali mein upar chadhta hai. Failna hi naap ban gaya!
- Phansa hua dhakkan: kai baar bade log achaar ke dabbe ka tight metal dhakkan gungune paani mein thoda rakh ke kholte hain. Garmi se metal ka dhakkan thoda fail ke dheela ho jaata hai.
🔗 NCERT Connection
Yeh topic Class 8 Science (Curiosity) ke is chapter se judta hai:
- Chapter 7: Particulate Nature of Matter: har cheez kanon se bani hai, kanon ke beech jagah hoti hai aur kan hilte rehte hain. Garmi se kanon ki halchal badhti hai. (CharuMam pe jald)
Saare chapters ki list: Class 8 Science (CharuMam)
📝 Recap
- Garam hone pe zyaadatar cheezein failti (expand) hain, thandi hone pe sikudti (contract) hain.
- Wajah: garmi se kan zyada kaanpte hain aur beech ki doori badhti hai. Kan khud bade nahi hote.
- 13 m ki steel patri 40°C garam ho toh lagbhag 6 mm lambi ho jaati hai.
- Failne ki jagah na mile toh patri tedhi (buckle) ho sakti hai, isliye joints pe chhota gap chhoda jaata hai.
- Sardi mein gap bada, garmi mein chhota. Nayi lambi welded patriyon ko kas ke pakad ke rakha jaata hai.
🎯 Quiz (5 MCQ)
1. Rail ki patriyon ke jod pe gap kyun chhoda jaata hai? (a) Paise bachaane ke liye (b) Garmi mein patri ko failne ki jagah dene ke liye (c) Baarish ka paani nikaalne ke liye (d) Train ki awaaz badhaane ke liye
✅ (b): garmi mein steel failta hai, gap use jagah deta hai. (a) Galat: gap se paisa nahi bachta, yeh suraksha ke liye hai. (c) Galat: paani ke liye patri ke neeche pattharon (ballast) ka intezaam hota hai. (d) Galat: awaaz toh ek side-effect hai, maksad nahi.
2. Garam hone pe loha kyun failta hai? (a) Uske kan bade ho jaate hain (b) Usme naye kan aa jaate hain (c) Kan zyada kaanpte hain aur beech ki doori badh jaati hai (d) Uska vajan badh jaata hai
✅ (c): zyada urja = zyada kaanpna = zyada jagah. (a) Galat: kan ka size nahi badalta. (b) Galat: koi naya kan nahi aata. (d) Galat: vajan wahi rehta hai.
3. Sardi ki subah aur garmi ki dopahar mein, patriyon ke beech ka gap kab bada dikhega? (a) Sardi ki subah (b) Garmi ki dopahar (c) Dono time barabar (d) Gap kabhi nahi badalta
✅ (a): thand mein patri sikudti hai, isliye gap bada. (b) Galat: garmi mein patri faili hoti hai, gap chhota. (c) aur (d) Galat: taapmaan badalne se patri ki lambai badalti hai, toh gap bhi badalta hai.
4. Agar bilkul gap na chhoda jaaye aur patri ko kas ke pakda bhi na jaaye, toh tez garmi mein kya ho sakta hai? (a) Patri pighal jaayegi (b) Patri chhoti ho jaayegi (c) Patri tedhi (buckle) ho sakti hai (d) Kuch nahi hoga
✅ (c): failne ki jagah na mile toh patri bagal mein mud jaati hai. (a) Galat: dhoop se steel nahi pighalta, uske liye bahut-bahut zyada taapmaan chahiye. (b) Galat: garmi mein patri lambi hoti hai, chhoti nahi. (d) Galat: failne ka zor bahut bada hota hai.
5. Khambon ke beech bijli ke taar thode dheele kyun baandhe jaate hain? (a) Taar sasta padta hai (b) Pakshi baith sakein (c) Taar garmi mein chhote ho jaate hain (d) Sardi mein taar sikudte hain; tight hote toh toot sakte the
✅ (d): dheela taar sikudne ki jagah deta hai. (a) Galat: dheela baandhne mein toh zyada taar lagta hai. (b) Galat: yeh maksad nahi hai. (c) Galat: garmi mein taar lambe hote hain, chhote nahi.
🧠 Socho aur Batao
1. Rajasthan ke registaan aur Himachal ke pahaad: dono jagah patri bichhaani hai. Kahan joints pe gap zyada sambhal ke rakhna padega aur kyun?
Jahan din-raat ya garmi-sardi ke taapmaan mein sabse zyada farak ho. Registaan mein din bahut garam aur raat thandi hoti hai, aur garmi mein patri dhoop se bahut tap jaati hai. Jitna bada taapmaan ka farak, utna zyada failna-sikudna, isliye wahan gap aur dekhbhaal ka khaas dhyaan rakhna padta hai. Matlab sirf “garam jagah” nahi, “farak” zyada maayne rakhta hai.
2. Mazdoor patri ko bahut thandi raat mein jod rahe hain. Kya unhe gap chhota chhodna chahiye ya bada? Kyun?
Bada. Thandi raat mein patri pehle se sikudi hui hai. Din mein dhoop padne pe woh sabse zyada failegi, isliye use zyada jagah chahiye. Agar garmi ki dopahar mein jod rahe hote (patri pehle se faili hui), toh chhota gap kaafi hota.
❓ FAQ
1. Kya har cheez garmi mein failti hai?
Zyaadatar cheezein haan: thos, drav aur gas teeno. Gas sabse zyada failti hai, drav usse kam, aur thos sabse kam. Par kuch khaas cheezein kuch taapmaan pe ulta bhi karti hain, jaise paani 0°C se 4°C ke beech garam karne pe sikudta hai. (Yeh humne SN-01 mein barf wale topic mein dekha tha.)
2. Train ki “dhadak-dhadak” awaaz ka gap se kya lena-dena hai?
Jab pahiya ek patri se doosri patri pe jaata hai, toh jod ke chhote gap aur halke-se uchh-neech pe ek jhatka lagta hai. Har jod pe yahi hota hai, isliye ek taal mein “dhadak-dhadak” sunai deta hai. Welded lambi patriyon pe joints bahut kam hote hain, isliye wahan safar shaant lagta hai.
3. Fishplate kya hoti hai?
Do patriyon ke jod pe dono taraf lagi steel ki patti, jo bolt se kasi hoti hai. Yeh dono patriyon ko ek seedh mein pakad ke rakhti hai, par itni jagah deti hai ki patri garmi mein thoda khisak ke fail sake.
💖 CharuMam Motivation
Patri ki taqat uske sakht hone mein nahi, use thodi jagah milne mein hai. Jagah mili toh garmi mein bhi seedhi rahi; jagah nahi mili toh mud gayi.
Aap bhi aise hi ho, beta. Har din har cheez ekdum “tight” plan karoge toh thoda-sa pressure bhi aapko tedha kar dega. Apne din mein thoda gap rakho: thoda khel, thoda aaraam, thodi hansi. Yahi chhota gap aapko lambi race mein seedha aur mazboot rakhega. 🌱
— CharuMam
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