Dheeme Praakritik Badlaav
Class 7 Science · Chapter 5: Hamare Aas-paas Badlaav: Bhautik aur Rasaayanik · NCERT Curiosity section 5.7
Seekho
Trek par Zoya aur Kabir chattaan ki talhati par ret, mitti aur toote pattharon ke dher, aur naale mein chikne gol kankad dekhte hain. "Chattaanein sthaayi lagti hain," Kabir kehta, "par ye unke tukde hain." Aise dheele padaarth ko avsaad (sediment) kehte.
Chattaanon ka dheere tootna apakshay (weathering) hai. Din ki garmi aur raat ki thand, daraaron mein jamta paani, aur chattaanon mein ghusti jadein unhe todte: bhautik apakshay. Paani aur hawa khanijon se kriya bhi kar sakte: loha wali kaali basalt chattaan dheere-dheere iron oxide ki laal parat paati, rasaayanik apakshay.
Hawa, behta paani aur barf toote tukde le jaate: ye kataav (erosion) hai. Nadi ke kankad aapas mein ragadkar chikne bante. Hazaaron saalon mein apakshayit chattaan paudhon aur jaanwaron ke avshesh se milkar mitti banti. Ye badlaav bahut dheeme, par pahaad, ghaatiyaan aur samudra-tat gadhte.
Explore: apakshay ya kataav?
- Har ek sort karo.
Yaad rakho
- Apakshay chattaan todta, bhautik (garmi, barf, jadein) ya rasaayanik (basalt par iron oxide).
- Kataav tukde le jaata; yugon mein apakshayit chattaan mitti banaati.
Quick check
Basalt chattaan ka saalon mein laal hona kiska udaharan?
- rasaayanik apakshay
- kataav
- dahan
- ulta hone wala badlaav
Answer
rasaayanik apakshay. Chattaan ka loha hawa-paani se iron oxide banaata.
Socho
Nadi ke kankad gol-chikne aur pahaadi ki chattaanein nukeeli kyun?
Ek answer
Nadi ke kankad lagaataar ludhakte aur ragadte, to kinaare ghis jaate. Pahaadi chattaanein haal mein tooti aur ghisi nahi.
Practice
Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.