[0:00]Hello class 9, kaise ho aap sab? Aaj hum karenge class 9th ka Social Science ka Chapter number 2, jiska naam hai Shaping of Earth's Surface. Beta ye jo chapter hai na ye bachon ko samajh mein hi nahi aata, bahut hi zyada boring lagta hai kyunki ye geography ka chapter hai. Lekin aaj is chapter ko hum itne acche se padhenge ki aapke saare questions ho jayenge, aapke jo bhi doubts honge wo clear ho jayenge. Aur saath mein, aapko ye pura ka pura chapter samajh mein aa jayega, bahut zyada bada lecture nahi hoga, theek hai, bahut kam time mein hum is chapter ko khatam kar lenge. Toh sabse pehle samajhte hai ki hum kaun-kaun se topic is lecture ke andar padhne wale hai, theek hai. Hum padhenge interior of Earth, beta Earth ke andar ke baare mein padhenge kaun-kaun si layers hoti hai. Theory of Plate Tectonics, Plate Tectonic ki theory padhenge, kisne di thi, kab di thi, kya bola tha us baare mein. Tectonic Plate jo hoti hai wo move kis tarike se karti hai wo padhenge, weathering kya hota hai, erosion kya hota hai, dono mein difference bhi padhenge aur saath mein hi aapke paper mein aata hai theek hai. Importance of weathering padhenge aur saath mein agent of gradation padhenge, kehne ka matlab hai ki jo Earth ki surface hai, usko level mein kaise le ke aa sakte hai, wo process padhenge, kaun le ke aata hai wo padhenge. Kuch major landforms padhenge aur unke formation padhenge ki kaise wo bante hai. Ek aur cheez, landforms padhenge aur natural disaster padhenge, in saare topic ke baad mein aapka ye chapter jo hai wo khatam ho jayega. Aage samajhte hai. Ye kuch questions hai, pehle hum chapter padh lenge theek hai, abhi hi iska screenshot le lo. Le liya, theek hai. Jab hum chapter padh lenge, uske baad mein aapko ye questions padhne hai aur dekhna hai kya aap inko solve kar pa rahe ho, theek hai, bahut saare bachon ne mujhe comment section mein likha tha ki humein chapter ke question bhi provide kar do. Toh ye questions hai, abhi se hi dekh lo, lekin pehle chapter padh lete hai. Samajh mein aa gayi baat? Ab samajhte hai bhai, start karte hai chapter, sabse pehli baat toh ye samjho ki jo Earth ki surface hai na, wo puri ek jaisi nahi hai, theek hai, kahin par registan hai, kahin par pahad hai, kahin pe samudra hai, toh wo puri ek jaisi nahi hai. Toh yahan pe likha hai, the surface of Earth is not uniform, jo Earth ki surface hai wo uniform nahi hai. Ye alag alag jagah pe alag alag hai, theek hai, uneven. Shape over millions of year by powerful forces aur aisa hua kyun ye alag alag shape ki kyun bani, kyunki iske upar na kuch powerful forces jo hai wo act kar rahi hoti hai. Do type ki hoti hai, pehla hota hai kya, internal forces aur dusri kaisi hai beta external forces. Jo internal forces hai wo hai kya, plate ki movements, earthquake, volcanic activity, aur inke wajah se bante hai bachon kya, mountains bante hai, plateaus bante hai aur valleys banti hai. Samajh mein aayi itni baat? Agli cheez hai external forces jaise ki hawa, pani aur ice, toh wind, water and ice. Weathering and erosion, iske wajah se hota kya hai, ek jagah ki jo land hoti hai wo hat ke kahin dusri jagah chali jati hai. Kya abhi tak aapko itni baat samajh mein aayi kya bola maine? Maine bola ki bhai jo Earth ki surface hai wo uniform nahi hai, wo uneven hai, alag alag hai kyun, kyunki uske upar kuch powerful forces jo hai wo act kar rahi hai, do type ki hoti hai, kuch hoti hai internal and kuch hoti hai external. Internal hoti hai plate movement, earthquake, volcanic activities, inke wajah se mountain bante hai, plateaus bante hai aur valleys banti hai. External forces ki agar hum baat kare toh bhai wind, water, weathering, erosion, iske wajah se kya hota hai, ek jagah ki surface jo hoti hai wo hat jati hai and dusri jagah pe ja ke wo deposit ho jati hai. Samajh mein aa gayi itni baat, theek hai, aage samajhte hai. Agla topic hai hamara interior of the Earth layers, bhai jo Earth ke andar ki layers hai na uske baare mein hum baat karenge. Lekin bina diagram ke toh humein cheeze samajh mein nahi aati toh pehle hum dekhenge ek diagram, samjho. Sabse pehli baat toh jo sabse upar wali layer hai isko hum bolte hai bachon kya, crust, kya bolte hai crust, yaani ki jiske upar abhi main khadi hu. Theek hai, jiske upar abhi aap baithe ho, ye jo sabse upar wali Earth ki surface hai isko hum kya bolte hai, crust bolte hai, kya bolte hai bachon crust. Uske baad mein jo andar wali puri ye layer dikh rahi hai aapko isko hum kya bolte hai mantle, kya bolte hai bachon mantle. Agli cheez, phir hota hai last mein core, core jo hai wo do parts mein divide hota hai, ek hota hai outer core, ek hota hai inner core, kya itni baat samajh mein aa gayi hai. Ab iske baare mein padh lete hai kya kya cheeze hoti hai, toh bhai crust kya hai, outermost, thinnest layer jahan par hum rehte hai, theek hai, sabse bahar wali, sabse patli layer jahan par hum rehte hai usko hum bolte hai. Agli cheez yahan par kya hai rocks hai and kya hai minerals, ye thicker hoti hai continents mein, theek hai aur thinner hoti hai kahan par oceans mein. Yahan pe ek baat samjho aisa kyun bola, kyunki bhai ocean ho ya phir Earth crust jahan pe hum rehte hai, dono jagah ko hi hum crust bolenge, toh yahan par, continent mein kya hoti hai thicker hoti hai, moti hoti hai, theek hai aur oceans mein kya hoti hai thinner hoti hai. Example ki agar hum baat kare toh jahan par abhi hum chal rahe hai aur ocean ka floor jo hai wo crust ka example ho jayega, itni baat samajh mein aa gayi hai kya. Screenshot aap log lete rehna theek hai baad mein aap log bolte ho ki aapne jagah nahi di thi.
[4:41]Agli cheez samajhte hai mantle, toh ye hoti hai kahan par below the crust, crust ke niche. Much thicker, kaisi hoti hai thicker hoti hai aur bani hoti hai kiski magma ki, magma ka matlab kya hota hai, magma ka matlab hota hai molten jo patthar hota hai na usko hum magma bolte hai. Toh molten ya phir aap bol sakte ho semi molten material, theek hai, kyun ho jata hai ye molten, kyunki yahan pe bahut zyada heat hoti hai aur bahut zyada kya hota hai pressure hota hai. Example ki agar hum baat kare toh volcanic lava jo hota hai na wo yahin se nikalta hai. Theek hai volcanic eruptions jo hote hai unmein se jo lava nikalta hai wo mantle hota hai. Agli cheez hai core, toh ye do parts hote hai, ek hota hai innermost, ek hota hai kya outermost. Ab samjho jo innermost hota hai wo kaisa hota hai hottest layer hai aur ye bana hota hai kiska NIFE, NIFE matlab NI se Nickel and FE se Iron. Divide hota hai do parts mein jaisa humne padha abhi, outer core, liquid state, inner core solid hoti hai, theek hai, kiske wajah se bahut zyada pressure ke wajah se. Ye generate karta hai kya Earth magnetic field, samajh mein aa rahi hai baat? Toh jo core wala part hai wo magnetic field ko generate karta hai, aage badhte hai.
[5:47]Haan, ab yahan par dekho beta, humne jo bhi kuch padha usko ek baar short mein samajh lete hai. Toh crust jo hai wo thinnest layer hai, mantle jo hai usmein magma hota hai, theek hai, core jo hai uske do parts hote hai, kya NIFE yaani ki Nickel and Iron, theek hai. Ab ek baat samjho, human bodies ke andar agar mere ko organs dekhne hai toh main kaise dekhungi, toh hum x-ray karayenge bhai, theek hai, x-ray ke through hum pata lagayenge. Lekin Earth ke surface ke andar kaise pata lagaya humne ki ye alag alag parts hai, toh wo pata lagane ke liye hamare paas hoti hai kya, seismic waves, kya hoti hai bachon seismic waves, toh jo seismic waves hai uski study kar ke humne pata lagaya ki Earth ke andar alag alag kya hai, layers hai. Aage badhte hai. Agla topic hai aapka theory of plate tectonics, jo plate tectonics hai unki theory. Pehle toh mujhe ye batao kya aapko pata hai ki plate tectonics hai kya? Dekho, pehle na jitne bhi continent hai wo saare ke saare na jude hue the. Theek hai, wo sara pura ek hi tha, lekin phir kuch movements hui, theek hai, kuch forces lagi internal forces, kuch external forces. Aur ye na kuch alag alag parts mein toot gaye, yaani ki jo Earth ki sabse upar wali layer hai na lithosphere. Wo lithosphere kuch parts mein alag alag mein toot gayi unhi ko humne kya bol diya tectonic plates bol diya, kya bolte hai bachon tectonic plates. Toh jo Earth ki crust hai wo divide ho gayi several layers mein, theek hai, kuch small tectonic plates mein. Theek hai, itni baat samajh mein aa gayi aur ye kya hoti rehti hai constantly slowly slowly move karti rehti hai. Ab ek baat samjho, jab ye move kar rahi hai toh humein dikh kyun nahi rahi, theek hai, jaise bhai aapke haath mein nails hote hai, theek hai, nails ki movement bhi hoti hai, yaani ki growth hoti hai. Ab jo growth hoti hai wo daily daily toh dikhti nahi hai, lekin bhai ek hafte baad do hafte baad aapko kaatne padte hai nails, kyun, kyunki unki movement ho rahi thi unki growth ho rahi thi, samajh mein aayi baat. Toh ye movement bahut slow thi, theek hai, lekin bahut time baad millions of years baad humein dekhne ko milta hai ki okay changes ho chuke hai, samajh mein aa rahi hai baat. Theek hai, agar aapko samajh mein aa raha hai toh aap comment section mein zarur likh dena ki aapko topic samajh mein aaya. Theek hai, aage samajhte hai, major tectonic plate. Ab bhai samjho, yahan pe na tectonic plates toh bahut saari hai, lekin kuch major ke naam de rakhe hai aur agar aapse question puchega toh aapse bolega ki bhai map ke andar na inko, batao, locate karo ki kahan par kaun si plate hai. Toh bhai samajh lete hai jaisa paper mein aayega waisa padh lete hai. Samjho, yahan par sabse pehle aapko kya dikh raha hai, first number maine likha hua hai toh bhai kaun si plate hai ye, eurasian plate hai, kaun si plate hai, pen change kar lete hai, theek hai, kaun si plate hai bachon eurasian plate. Second kya hai bachon African plate, third kya hai bhai third, Australian plate. Fourth kaun si hai Pacific plate, fifth North American Plate and sixth South American Plate, itni baat samajh mein aayi, theek hai, yahi saare naam hai jo humne pichli wali slide par likhe hue the. Ye dekho, eurasian plate, african plate, indo-australian plate, pacific plate, north american plate and south american plate, theek hai, ye saare kya hai aapki kuch major plates hai. Ab samjho ye jo theory thi wo kisne di thi sabse pehli baat, toh sabse pehle di thi ye kisne Alfred Wagner ne. Theek hai, kisne di thi Alfred Wagner ne, lekin isko prove kisne kiya tha, Indian geologist the jinka naam tha K.S. Valdiya, inhone kya kiya tha strong evidence diya tha aur unhone kaam kiya tha kiske upar formation of Himalayas ke upar. Ek baat suno, jab tectonic plates jo hoti hai wo kya hoti hai, paas aa jati hai, theek hai, jab paas aa jayengi toh kya ho jayega, koi bhi mountain banega, aise hi Himalayas bana tha. Ab bana kaise tha Himalayas, toh dekho idhar dekho, diagram pe chalte hai. Jab eurasian plate aur indian plate takrai aur aapas mein mili toh kya bana tha, Himalayas bana tha, samjhe baat, ab ek baat samjho aur, ghar wala normal example le ke cheezon ko samajhte hai. Carpet hota hai carpet, theek hai, carpet ko agar main dono taraf se aise pakad ke utha do, theek hai, pura carpet hai, usko main dono taraf se pakad ke aise utha do toh kya ban jayega, aise kar ke structure ban jayega. Samajh pa rahe ho baat, dekho, idhar se carpet, idhar se carpet, maine aise pakad ke utha diya, toh aisa structure ban jayega, kya ye kuch mountain jaisa structure nahi hai, same aise hi mountain formation bhi hota hai, itni baat clear hai sabhi ko, theek hai. Ab aage samajhte hai bachon screenshot le lena. Hmm, aage samajhte hai. Ab hai kya, types of plate movements, bhai jo plate movement hai wo kis-kis type ki hoti hai, toh teen type ki hoti hai bachon kitne type ki hoti hai teen, sabse pehli hoti hai divergent movement, kya hoti hai sabse pehli divergent movement.
[10:14]Ab samjho, divergent movement kya hota hai, jab plate jo hai wo dur chali jati hai, plates move apart, jab plates chali jati hai dur dur chali jati hai. Toh yahan pe dekh rahe ho ye plates kya ho rahi hai, dur ja rahi hai, new crust forms, yahan pe kya hota hai, naya crust ban jata hai, jiske wajah se volcanic activity hoti hai. Ab ek baat samjho, jab plates dur dur jayengi toh beech mein gap khali bach jayega, toh jo andar molten bhara hua hai pura hai na wo kya ho jayega bahar nikal ke aa jayega, usi ko hum kya bolenge volcanic eruption bolenge, kya bolenge volcanic eruption. Theek hai, iska example bhi de rakha hai Mid-Atlantic Ridge, agli cheez hai kya bachon convergent movement, ismein kya hota hai, dono convert yaani mil jati hai aur isi ke wajah se toh Himalayan formation hua tha jo maine upar, piche abhi samjhaya tha. Toh yahan pe plate jo hoti hai wo collide kar jati hai, yahan pe mountain ban jate hai, example kya hai Himalaya aur abhi maine piche bataya bhi tha ki Himalaya kaise bana, jab Indian aur Eurasian plate mil gaye. Clear hai itna, samajh mein aa rahi hai baatein, theek hai, bahut fast toh nahi chal rahe hum log, sahi sahi hai, okay. Ab samjho transform movement, ismein kya hota hai transform mein na, jo do plates hoti hai wo slide karti hai, theek hai, side side mein kya hoti hai slide karti hai. Toh yahan pe likha hai plates slide past each other, ek dusre se slide kar rahi hoti hai. Toh opposite direction mein karti hai jiske wajah se kya hota hai strong earthquake aata hai, kya aata hai strong earthquake. Kya itni baatein clear hai, koi dikkat toh nahi hai, tumne bachpan mein zarur suna hoga ki bhukamp kaise aata hai, earthquake kaise aata hai. Toh tumne suna hoga ki Earth ke andar na kuch plates hai, jo aise hil rahi hai, unke hilne se na sab kuch hil ja raha hai, hai na wahi hai same. Aage badhte hai. Agla topic hai bachon kya weathering. Ab samjho weathering ka matlab kya hota hai, weathering ka matlab hota hai ki jo bade bade patthar hai, agar wo toot jaye aur chote chote patthar ban jaye ya phir usse mitti ban jaye toh usko hum bolte hai weathering, kya bolte hai bachon weathering. Yahan pe likha hai, breaking down of rocks into small piece, jo bade bade rocks hai wo chote chote piece mein agar toot jayenge, usi jagah par koi movement na kar ke toh usko hum kya bolenge weathering. Ab ye hota kyun hai, temperature change ke wajah se ho sakta hai, water ke wajah se ho sakta hai ya phir air ke wajah se bhi ho sakta hai, theek hai. Ab teen iske wo hai methods, kaise weathering hogi, toh pehla hai physical, dusra hai chemical and teesra hai biological, itni baat clear hai kya. Theek hai, pehla kya hai physical, dusra. Chemical aur teesra biological. Ab samjho physical, toh breaking down into small piece by physical means. Physical method ke through agar bada sa patthar chote chote parts mein toot jata hai toh usko hum kya bolte hai physical weathering bolte hai. Ab hua kya, due to temperature change, temperature change ho jayega ya phir flow of water ho jayega ya phir pressure release ho jayega, iske wajah se kisi bhi ek rock ke upar crack pad jayega, samajh gaye bachon. Ye jo maine diagrams lagaye hai wo aapki new NCERT ke hi diagrams hai, theek hai, jab apki new updated book aayegi na uske diagrams hai. Aage samjho chemical, toh chemical mein kya hoga break down due to chemical reaction, chemical reaction, ab bologe ki ma'am ek baat batao, ye chemical dalega kaun. Toh acid rain hoti hai acid rain, uska jo acid hoga wo bhi toh acid hi hai wo bhi toh chemical hi hai, toh due to water, oxygen, acids. Water, oxygen, acid reaction karenge, theek hai, mineral ke upar aur ye toot jayega aur ya phir ho sakta hai iske upar kya lag jaye, rust lag jaye, kya lag jaye bachon rust and rusting ka matlab toh aap logo ko pata hi hoga. Agar nahi pata toh rusting ka matlab hota hai zung lagna, theek hai aur zung ke wajah se toh loha bhi toot jata hai toh patthar bhi toot jayega, theek hai. Agli cheez hai biological, toh weathering by plant, animal and micro-organism, agar kisi plant ke wajah se, animal ke wajah se ya phir micro-organism ke wajah se koi bada sa patthar toot jaye toh usko hum kya bolte hai biological method, theek hai. Ab hota kya hai, plant root in crack, plant ke roots jo hote hai unmein dekho, kahin kahin pe kya hota hai ki patthar ko tod ke ek plant nikalta hai aur wo full growth kar jata hai aur jo patthar hota hai wo toot jata hai roots ke wajah se, usi ka yahan pe example de rakha hai. Ya phir ho sakta hai koi animal hai jo uske andar apna ghar bana le aur dheere dheere wo jo kya ho jaye, crack ho pehle uske baad mein wo pura ka pura hi toot jaye, samajh mein aa gayi baat? Ab bologe theek hai ma'am humne padh liya ki bada sa patthar hai, toot gaya, theek hai, chote chote patthar bana diye ya phir ho sakta hai mitti hi bana di ho, toh isse humein kya fayda? Ab samajhte hai kya fayda hai, samjho importance of weathering, kya importance hai, sabse pehli cheez, help in soil formation, soil kaise banegi, toh jab bade patthar tutenge jabhi toh soil banegi bachon, jab bade bade patthar tutenge toh kya banegi soil ban jayegi. Agli cheez samjho, essential for agriculture and plant growth, isi wajah se agriculture ho payega and plant ki growth ho payegi. Breaks rock into smaller pieces, jo bade bade rocks honge wo chote chote pieces mein toot jayenge jiske wajah se kya ho jayega erosion easier ho jayega. Erosion ka matlab pata hai, erosion ka matlab hota hai kya ki bhai patthar tha, theek hai, bahut bada wo chote chote parts mein pehle toh toot gaya, mitti ban gayi, kya ban gayi mitti, soil ban gayi. Ab jo soil hai na, wo ek jagah se uth ke dusri jagah chali gayi with the help of water ya phir air, kisi ki bhi help se, theek hai, isko hum kya bolte hai erosion bolte hai. Agli cheez, help in releasing minerals into the soil, ab dekho hoga kya, ki soil ko minerals bhi dene hai, kaun dega, wo patthar tutega aur pure mein wo mix ho jayega, theek hai. Agli cheez, creates natural landforms, iske wajah se kya hota hai kuch natural landforms bante hai jaise ki caves bante hai, arches bante hai and valleys banti hai. Help in the natural recycling of minerals, minerals ki natural recycling ke liye bhi ye kya hota hai useful hota hai. Weathering is necessary process before erosion can take place. Ab dekho agar erosion karana hai toh pehle weathering karani padegi, yaani pehle bade patthar ko tod ke mitti banani padegi, uske baad mein hi toh mitti ek jagah se dusri jagah bahegi, samajh mein aa gayi baat, isliye ye jo line likhi hai bahut important hai. Weathering jo hai wo necessary hai weathering jo hai wo necessary process hai before erosion can take place jab erosion ho usse pehle. Theek hai, ab aage samajhte hai. Difference between weathering and erosion. Toh bhai samjho weathering mein kya hota hai, break down break breaking rocks in same place, jo rock toot'ta hai wo ek hi place pe hota hai. Lekin erosion ka matlab hai carrying away weathering material, jo bhi weathering material hai usko dur le ke jana, yahan pe koi movement nahi hoti, yahan par movement hoti hai. Yahan pe kaun-kaun se agent hai temperature, air, water and plant, yahan pe kaun-kaun se hai toh running water, wind, glaciers and waves, theek hai. Agli cheez yahan pe process kya hota hai sirf aur sirf break hota hai, yahan pe kya hota hai remove hota hai, transport hota hai and deposit hota hai, yaani hat jata hai wahan se transport ho jata hai, chala jata hai and deposit wahan pe ja ke ikaththa ho jata hai kisi aur jagah pe. Samajh mein aa gayi baat, generally slow hota hai ye slow bhi ho sakta hai and fast bhi ho sakta hai. Yahan pe kya hota hai example ki agar hum baat kare toh cracking of rocks, rock jo hai wo toot jata hai, theek hai, and yahan pe kya hota hai jo river hai wo soil ko apne saath le ke chali jati hai, theek hai. Aage samajhte hai bachon isko na isko star mark kar lena, screenshot bhi le lena, important hai. Aage samajhte hai, agle agent of gradation, pehle ye samjho ki gradation ka matlab kya hota hai, gradation ka matlab hota hai ki jo Earth ki surface hai na usko ek shape mein le ke aana. Toh wo kaun-kaun se agent hai jo Earth ki surface ko shape mein lekar aate hai, alag alag shape mein, theek hai, samjho. Toh levelling of Earth's surface through weathering, erosion, transportation and deposition, bol rakha hai ye saare toh process the weathering ke through, erosion ke through, transportation ke through and deposition ke through. Lekin kaun kaun agent hai jo ye kaam karte hai, toh sabse pehli cheez toh hai bhai kya river, kya hai river. Ab samjho river ke through kaise, toh river jo hogi wo pehle kya karegi erosion, transportation and deposition, aur iske wajah se kya banega V-valleys banengi, kya banengi bachon V-valleys, ab dekho ye dikh raha hai tum logo ko. V-dikh raha hai, V-shape ki kya ban rahi hai valleys ban rahi hai, kiske wajah se ban rahi hai ye river ke wajah se, waterfalls banenge and floodplains banenge. Kya iski photo hai, floodplains kahan hai, ye wale structure ko bolte hai floodplains. Samajh mein aa gayi baat, iska matlab hai ki side side mein kya hoga pura plain surface hoga aur beech mein se nadi ja rahi hogi, samajh mein aa rahi hai itni baat. Agli cheez samjho, example Ganga and Indus Rivers, koi dikkat toh nahi hai, itni baat samajh mein aa gayi hai, theek hai. Agli cheez samjho wind ke through, pehle humne kya padha river ke through ab hum padh rahe hai kya wind ke through, toh bhai hoga kya, wind ke through ka matlab hai ki jab bahut tez hawa lagegi pattharon mein toh kya hogi shape change ho jayega. Toh most active hota hai ye dry places mein jaise ki desert region mein, theek hai, ismein jo process hota hai isko hum kya bolte hai abrasion, yaani ki hawa se takra takra ke patthar ka shape change ho jana. Theek hai, ab iske wajah se banta kya hai, isse banta hai sand dunes, kya banta hai sand dunes, iska matlab hai ye wale structures, dekh rahe ho beta sand ke upar ye kuch structures bane hue hai inko hum kya bolte hai sand dunes bante hai. Toh ye itne saare photos itne saare diagrams isliye lagaye hai tak ki aapko easily cheeze samajh mein aa jaye, theek hai, agar sirf hum word sunte rahenge toh humein na aadhi cheeze samajh mein hi nahi aayengi, samjhe. Toh isliye har cheez ki photo agar maan lo koi aisi cheez ho beech mein jo aapko samajh mein na aayi ho ya phir maine uski photo na dikhai ho socha ho ki bahut common hai ye toh, theek hai toh uski photo aap khud se search kar lena ya phir comment section mein mujhse pooch lena main aapko reply kar dungi, samajh gaye bachon itni baat, theek hai. Agli ek bahut hi interesting cheez mushroom shaped rock, ab dekho beta ye bhi NCERT ka maine diagram lagaya hai yahan pe main dikhati hu aapko, ye dikh raha hai mushroom shape ka hai, kaisa hai ye mushroom shape ka. Hawa se kya hua jo niche ka hai na pura wo ho gaya, theek hai, wind ke wajah se pura shape hi change ho gaya aur kaisa ban gaya ye mushroom jaisa ban gaya, kaisa ban gaya mushroom jaisa, kya itne mein koi dikkat hai, samajh mein aa gayi hai saari baatein, example ho jayega Sahara desert and Thar desert. Okay, agli cheez hai waves toh agar waves pani ki waves ke through agar shape change ho jaye pattharon ka toh usko hum kya bolenge waves ke through ho raha hai. Toh erode coastal rocks, deposit sediments, sediments ka matlab pata hai jo bhi pani ke saath mein jo bhi cheeze aa rahi hai usko hum kya bolenge sediments bolenge. Yahan pe kya bante hai cliffs bante hai, kya bante hai bachon cliffs, caves, arches and beaches, ab samjho iski photo bhi main aapko dikhati hu. Kya aapko ye wala dikh raha hai photo, theek hai ye bhi NCERT ka photo hai, ye kya hai bachon cliffs hai, kya hai ye cliffs structure. Yaani ki lehron se wave se jab patthar tootne lag jaye toh usko humne kya bola cliffs bola, theek hai and saath mein piche diya gaya tha arches toh is is wale structure ko kya bolte hai arches, yaani ki nature mein khud se ek gate jaisa structure ban jana and kya likha hua tha caves likha tha, ya likha tha caves, yaani ek gufa ban jana isko bhi hum kya bolenge waves ke through ye saare shapes bante hai. Agli cheez samajhte hai kya hai glaciers, kya hai bachon glacier, toh hota kya hai yahan pe, abrasion and plucking, toh U-shaped valleys banti hai. Ab ek baat samjho, jab bhi river ka water aayega toh V-shape ki valleys banengi aur jab bhi glacier se aayega toh U-shape ki valleys banengi, dono mein difference samajh mein aaya, theek hai. Rivers ke through V-shape, theek hai aur glaciers ke through U-shape ki, koi dikkat toh nahi hai, example yahan pe kya ho jayega Himalayan glacier, shayad maine iski bhi photo toh lagayi hi hogi, haan ye rahi, samajh mein aa rahi hai baatein. Ab padhte hai last and most interesting.
[21:03]Agla kya hai under ground water, kya hai bachon under ground water. Ek blank page lete hai, haan, toh maan lo ki bhai ye surface hai, yahan pe kuch darare padi, theek hai, in dararon mein se kuch pani aaya jo aise kar ke jam gaya, alag alag alag alag structures mein. Same niche se bhi pani hai, yahan pe kya hua, aise kar ke pani jo hai wo jam gaya, usne kuch structures banaye, theek hai, aur unko humne kya bola. Stalactite aur kya bola Stalagmite, ye do naam humne diye, ab ek baat samjho, achha ye pani jama kyun abhi bata deti hu, kyunki yahan par jo temperature tha na wo low tha. Temperature bahut low hone ke wajah se jo pani aa raha tha wo kya ban gaya, yaani structures mein ban ke jama ho gaya, ikaththa ho gaya, samajh mein aa rahi hai baat? Ab main aapko diagram dikhati hu real wala, dekho bachon, ye upar se pani aa gaye aise jamta ja raha hai aur ye niche se, theek hai, kyun ho raha hai, kyunki yahan ka jo temperature hoga na wo bahut zyada kam hoga, achha agar koi structure ye jo dono hai ye mil jaye, kya ho jaye ye dono ke dono mil jaye toh hum usko kya bolenge column, kya bolenge bachon columns. Theek hai, aage samajhte hai, ab hai kya rivers agent of gradation detail, humne jo alag alag abhi padhe agent of gradation unmein se pehle hum river padh rahe hai, samajh mein aa rahi hai baat, theek hai. Ab dekho hota kya hai jo pani aata hai wo do jagah se aa sakta hai ya toh Himalayas se aa raha hoga ya phir glacier se aa raha hoga, hai na ya toh Himalayas se ya phir glacier, dono hi bahut upar hai. Ab jitna koi cheez upar hogi na utna uska slope steeper hoga, paina slope hoga.
[22:38]Paina slope hoga, for example agar main, main toh abhi aisa kuch hai nahi. For example agar main kya karu, aise kar ke yahan se kisi cheez ko feku ab main pencil ko toh nahi fek sakti hu bhai, theek hai, agar main isko niche kar ke feku toh shayad jaldi girega aur aise kar lu toh dheere dheere girega, samajh mein aayi baat, yaani ki jitna zyada paina slope hota hai jitna steeper hota hai utni tez cheez aati hai. Ab mountain pe se aur glacier pe se jab pani aayega toh iski speed kya hogi bahut zyada fast hogi. Kyun, kyunki jo slope hai wo steep hai, yahan pe kya banega, V-shape valleys ban jayengi and waterfall ka formation ho jayega, itni baat clear hai abhi tak, theek hai. Ab jab middle mein aa jata hai ye middle mein toh kya ho jayega speed jo hai wo medium ho jayegi, theek hai aur kya ban jayenge floodplains ban jayenge jo maine abhi aapko piche dikhaye the. Lower region mein jab wo aayega toh speed jo hai wo slow ho jayegi, flat land ho jayega aur deltas wagera ka formation ho jayega. Ab main thodi si interesting cheez dikhati hu, dekho Oxbow lakes, bhai dekho hamesha yaad rakhna kuch bhi aap padhte ho, kuch bhi naya padhte ho uski photo search karo. Abhi toh aapke paas sab kuch hai na Google hai, toh Google pe aap photos dekho aapko bahut interesting lagne lag jayengi cheeze, toh jaise ye Oxbow lake hai toh ismein kya hota hai na ye kuch structures aise aise ghum ghum ke ban jate hai aur humein lagta hai shayad ye khud se banaye hai, nahi ye khud se nahi banaye humne ye naturally bane hue hai, samajh mein aa rahi hai baat, theek hai. Aur ye kahan pe bante hai lower course mein bante hai sabse niche maidan mein bante hai. Aage samajhte hai bachon major landforms ka overview, jo jo major landforms hai phir ek ek kar ke inke baare mein padhenge. Toh sabse pehla hai bachon kya mountains, uske baad mein plateaus, plains, theek hai, valleys, desert and coastal landforms, phir inke baare mein padhenge. Ab sabse pehle samjho mountains kya hai, toh ye bahut high hote hai, very high, inka jo slope hota hai wo bahut steep hota hai, kab bante hai ye jab tectonic plate ki movement hoti hai. Kaisi wali movement, convergent, divergent ya phir transform, aapko batana hai comment section mein, theek hai. Agli cheez samjho, inke jo type hote hai wo teen type ke hote hai, fold, volcanic and block. Example hai Himalayas, Alps and Rocky Mountains. Plates ki agar hum baat kare toh ye bhi high hote hai, bhai ye bhi high hai, ye bhi high hai toh dono mein farak kya hai, ye aise hote hai, inke jo upar wali surface hoti hai flat hoti hai, kaisi hoti hai flat. Aur ye table jaisa lag raha hai table jaisa isko isliye hum kya bolte hai tablelands bhi bolte hai, kya bolte hai bachon tablelands, formed by tectonic uplift, kab banta hai ye jab tectonic uplift ho jate hai ya phir jab lava deposition ho jata hai. Jo mental wali thi hamari covering thi nahi, mental wali jo layer thi usmein se jab nikal jata hai deposition aur wo upar jama ho jata hai toh usko hum kya bolte hai plateaus bolte hai. Agli cheez samjho bhai plains toh ye large hote hai, flat hote hai aur ye bahut zyada important hote hai kiske liye human settlement ke liye. Ab samjho meri baat, bhai Himalayas pe kheti karna kitna mushkil hai aur rehna bhi kitna mushkil hai, same plateaus ke upar bhi lekin plains ke upar toh hum rehte hai, yahin pe hamara agriculture hota hai, yahin pe hum jobs wagera karte hai, kitna easy ho jata hai yahan pe rehna. Toh human settlement ke liye jo most important jagah hai wo kya hai bachon plains, agla samjho valleys, ye low areas hote hai between hills and mountains. Mountains ke jo beech ki jagah hoti hai na usko hum kya bolte hai hills bolte hai, aur jo mountains ke jo beech ki jagah hoti hai usko valleys bolte hai, theek hai, kuch bhi bol diya. Itni baat samajh mein aa gayi hai, okay, haan toh bhai U-shape ka kab banta hai jab glacier erosion hota hai ye maine aapko bata diya tha, iska example ho jayega kya Himalayan river valley. Agla hai bachon desert, desert kab bante hai, jab kisi jagah par 25 cm se bhi kam rain ho ek saal ke andar toh wo khud hi sookh jayega wahan ka temperature bahut zyada ho jayega usi ko hum kya bol denge desert bol denge, theek hai. Toh Sahara and Thar desert yahan pe example de rakha hai. Agla hai coastal landform, coastal ka matlab pata hai, tat yaani ki nadi ka kinara, theek hai, ab yahan pe kya hota hai. Ye kaise hote hai along shorelines yaani ki bank of river jo rivers wagera hoti hai unke kinare par hote hai, theek hai, shaped by waves and ocean current. Kya banta hai yahan pe cliffs, beaches, sea caves, arcs, theek hai, ye saari cheeze ban rahi hoti hai. Ab ek ek kar ke inke baare mein samajhna start karte hai. Bachon agar aap log yahan tak ruke hue ho, theek hai, aap is lecture mein yahan tak aaye ho pura dekh rahe ho. Aapko cheeze samajh mein aa rahi hai toh aap likh do ki aapko samajh mein aa rahi hai aur agar nahi samajh mein aa rahi hai toh aap wo bhi likh do. Taaki main kuch cheezon ko change bhi kar paun, samajh gaye baat, theek hai, aage samajhte hai. Toh mountains ke baare mein padhenge types padhenge and formations padhenge, sabse pehle fold mountain, bhai piche padha tha na humne fold, volcanic and block. Toh fold mountain kab bante hai, jab do plate collide karti hai, theek hai, jab do plate collide karti hai toh kya banta hai fold mountain banta hai jaisa ki Himalaya bana, theek hai, ek ek example yaad rakh lena. Agla hai volcanic, volcanic kab banega naam se hi samajh mein aa raha hai ki jab magma rise hoga cracks mein se. Yaani ki jo Earth ki surface pe cracks ho jayengi unmein se magma niklega aur kya banayega volcanic mountains banayega, samajh mein aa gayi baat, agli cheez hai kya block, fault mountain, isko samajhte hai. Hota kya hai pehli baat toh agar Earth ki surface ke niche bahut zyada kya hota hai pressure hota hai, kya hota hai bahut zyada pressure, jiske wajah se pad jate hai cracks, kya pad jate hai cracks. Aur in cracks mein se jo bhi wo hota hai magma wo nikal ke bahar aa jata hai aur deposit ho jata hai aur wo kya banata hai block mountain, toh land is uplifted due to faulting. Ek minute, magma nahi nikalta, magma toh idhar se nikalta hai, ismein kya hota hai jo land hota hai na wahi upar aa jata hai aur usi ko hum kya bol dete hai block mountain, ab samjho, agar maan lo tumhare example mein puche write difference between volcanic mountain and block mountain toh kya likhoge. Volcanic mein jo magma hota hai wo nikal ke aa jata hai bahar, theek hai, aur block mein kya hota hai jo darare ban jati hai, theek hai, unmein se jo land hota hai wo uplift ho jata hai, land bahar aa jata hai aur kya banata hai block mountain banata hai. Samajh mein aa gayi baat, aage badhe, theek hai, achha inke photos bhi de rakhe hai, theek hai, toh ye Himalaya hai, theek hai, ye Mount Fuji hai, ye photos de rakhe hai dekh lena ek bari. Aage samajhte hai, ab hai kya plains, valleys and desert jo hum aage padhne wale the. Toh plains jo hai wo kitne type ke hai bachon teen type ke, pehla hai river plain, dusra hai coastal plains and teesra hai glacial plains. Samjho, river plains formed by alluvial deposition of river. Ab kya hota hai, iska matlab hai ki river jab bah rahi hai toh uske saath mein jo bhi uske saath mein saman aa raha hai, theek hai, uske saath mein jo bhi mitti aa rahi hai, hai na jo bhi kuch aa raha hai uske saath mein wo sara jab deposit ho jata hai toh usko hum kya bolte hai river plain bolte hai aur ye bahut zyada fertile hota hai, theek hai, iska example ho jayega indo-gangetic plain, Ganga aur Indus plain. Ab agla kya hai coastal plain toh jab sea coast yaani river aur waves aati hai jo apne saath mein jo bhi kuch le ke aati hai wo deposit ho jata hai usko hum kya bolte hai coastal plains bolte hai. Glacial plain ki baat kare toh bhai jab glacier aata hai niche aur apne saath mein jo bhi kuch le ke aata hai wo deposit hota hai toh usko hum bol dete hai glacial plain. Agli baat samjhte hai valleys jo hoti hai wo do type ki hoti hai aur ye humne bahut baar pehle discuss kar liya pehli hoti hai V-shape valley aur dusri hoti hai U-shape, V-shape wali kab banti hai jab river se pani aata hai. U-shape kab banti hai jab glacier se aata hai, theek hai, agla desert wala bhi humne padh liya jab kahin par 25 cm se kam rain ho ek saal ke andar toh wo khud hi sookh jayega wahan pe temperature bahut zyada ho jayega sookha pad jata hai toh us jagah ko hum kya bolte hai desert bolte hai, theek hai. Aage samajhte hai. Coastal landforms ki agar hum baat kare toh beta ye most most most important hai, theek hai, dekho jitne bhi diagrams hai hamesha important hi hote hai. Kyunki CBSE ne pattern change kiya hai, CBSE ne books change ki hai toh shayad CBSE jo question banane ka tarika hai wo bhi change kar de, theek hai. Aur kuch creative le ke aaye jaise English mein creative kar di bahut saari cheeze, waise hi ho sakta hai ki baaki subjects mein bhi kar de toh be ready for that, theek hai. Ab samjho bhai lines of weakness, sabse pehla kya hai lines of weakness, ismein kya hota hai, ye kuch darare ban gayi hai. Ab sabse pehle jo waves hai na wo iske upar attack karengi kyunki ye sabse weak wala part hai, iske upar jab attack karengi toh kya ban jayega bhai ye ban jayega Blowhole, ismein se na fountain niklega, kya niklega fountain kyunki niche pani hai toh higher pressure ke saath mein upar niklega. Phir dekho jab bahut tez tez waves lagengi waves lagengi toh ye toot jayega toh kya ban jayega ye sea cave, achha ye pura khali nahi hua, sirf kya hua hai aadha cave gufa jaisa structure ban gaya, agar ye pura hi toot jayega toh kya ban jayega ye arch ban jayegi, kya ban jayegi arch jiski photo maine aapko dikhai thi. Achha agar ye pura hi itna toot gaya hat gaya sirf ye ye cheez bachi toh isko kya bolte hai stack, kya bolte hai stack, agar stack bhi aadha toot gaya toh kya banega stump, kya banega bachon stump. I hope aapko ye diagram samajh mein aaya hai, isko bana lena copy mein agar aapke paas book hai toh usmein likh lena cheezon ko lekin likh lena bahut important hai, theek hai. Aage samajhte hai landforms and their and natural disasters, toh bhai ye kuch landforms hai and kuch natural disasters hai. Samjho sabse pehli baat toh natural disaster hote kya hai, iska matlab hai suddenly kuch bhi kuch bhi aisa ho jaye ki life ko hani pahunche, theek hai. Ab dekho yahan pe kya likha hai sudden violent event, kuch bhi violent event ho jaye jaise ki earthquake, theek hai jaise ki landslide, ab samajhte hai earthquake kya hota hai. Sudden shaking from energy released when rocks break, shift along fault lines. Yaani ki jo Earth ki surface pe cracks ho jayengi unmein se magma niklega aur kya banayega volcanic mountains banayega, samajh mein aa gayi baat, agli cheez hai kya block, fault mountain, isko samajhte hai. Toh agar achanak se jo rocks hai wo kya ho jaye unmein movement ho jaye ya phir jo tectonic plates hai wo slide kar jaye toh kya aa jayega earthquake aa jayega, theek hai. Ye plate boundaries se linked hota hai. Agli cheez iske wajah se trigger kar sakta hai kisko landslide ko, tsunami ko and avalanche ko, ab samjho landslide kya hota hai. Landslide ka matlab hota hai agar achanak se rock, theek hai, rock ki, soil ki ya phir mud ki movement ho jaye niche ki taraf, pura niche ki taraf ho jaye, toh usko hum bolenge, ab main na hindi wale aise words use nahi kar rahi hu jo hum normal word use karte hai na. Isliye main sochti hu ki kya bolu, kya bolu, theek hai, toh yahan pe likha hai sudden downward movement of rock, soil, mud along slope under gravity, gravity ki taraf agar chale jaye, theek hai, toh kya ho jayega isko hum bolenge landslide. Cause, iske wajah se hoga kya, steep slopes ban jayenge, heavy rainfall hogi, earthquake bhi aa sakta hai, samajh mein aa gayi baat, ye most common hota hai kahan pe jahan pe hills hoti hai jahan pe mountain hota hai. Uske baad mein kya hai avalanche hai, ismein kya hota hai, rapid movement ho jati hai large mass of snow ki yaani bahut sara snow agar ek saath mein niche gir jaye toh usko hum kya bolte hai avalanche, achha inki photos nahi dikhai maine inke diagrams nahi dikhaye. Toh ye earthquake hai, ye toh aap logo ko pata hi hai, ye landslides hai, dekh rahe ho yahan ka pura jo land hai na wo niche chala gaya isko landslide bola. Avalanche mein kya ho raha hai, jo glacier hai na wahan se bahut sara barf ek saath mein niche gir raha hai, samajh mein aa rahi hai baat, theek hai. Aage samjho, agla kya hai dust storms, ye sab toh aap, ye toh aapne suna hi hoga, hai na, kya hota hai bahut saari na dhool aise ikaththi ho jati hai bahut tez tez hawa mein aur na aise aise ghumne lag jati hai.
[33:36]Toh strong winds lifting large amount of loose soil and sand, jo loose soil sand padi hoti hai, large amount mein usko le ke aise ghumne lag jati hai. Kahan par hota hai ye dry region mein hota hai, samajh mein aa gayi baat, iske wajah se kya ho jata hai effects kya hote hai phir visibility kam ho jati hai dikhte nahi hai cheeze, soil erosion ho jata hai aur health problems bhi badh jati hai, theek hai. Agar hum iske diagram ki baat kare toh ye raha, dust storm mein kuch bhi nahi dikh raha visibility kam ho jati hai. Agli baat samjho bhai importance of disaster mitigation, yaani ki bhai pehli baat samjho ki disaster mitigation hota kya hai, iska matlab hai ki jo bhi disaster ke wajah se harmful effect honge unko hum kaise kam kar sakte hai, theek hai, toh uska importance kya hai. Pehli baat toh ye dekho jo maine bataya wo likha hai disaster mitigation, measures and action taken to reduce harmful effect of natural disaster, theek hai, before they occur. Koi bhi natural disaster ho usse pehle hi kuch aisi cheeze kar li jaye kyun na jisse hum bach sake, theek hai, jiske bhai Japan mein toh aisi buildings banayi hai ki wahan pe earthquake aayi bhi toh bhi kuch na ho. Hai na waise hi kuch kuch cheeze humein bhi karni chahiye, sabse pehla kya hai, identify disaster-prone areas, aisi jagah pata lagao jahan par disaster ho sakte hai, theek hai. Agar aapko wo jagah pata chal jayengi toh shayad aap wahan pe jo apna construction ka main kaam hai wo nahi karoge, shayad aap wahan pe itni zyada population nahi basoge, samajh mein aa gayi baat, agli cheez hai kya, reduce risk through planning, planning karo, theek hai. Planning ka matlab hai ki jo government hai wo safe settlement karaye, theek hai, buildings wagera is tarike se banaye ki agar wahan pe earthquake aaye bhi toh wo building itni kamzor na ho ki wo seedha gir jaye, toot jaye, samajh mein aa gayi baat, theek hai. Agli cheez hai kya, protect human life and property, human life ko and property ko bachao, kaise, ek aisa plan banao ki bhai agar earthquake aata bhi hai toh logo ko kahan le ke jayenge, migration kaise karayenge unka, dusri cheez kya karau disaster drills yaani logo ko practice karao ki agar asliyat mein aisa ho jayega toh kaise bachoge, theek hai. Ye cheeze karani bhi bahut zyada zaruri hai, agli cheez promote sustainable development, avoid karo construction in high risk zone jaisa maine aapko pehle bataya ki aisi jagah jahan pe earthquake ke bahut zyada chances hai wahan pe zyada development aisa nahi karau ki wahan pe apni construction sites wagera mat chalau, itni baat samajh mein aa chuki hai. Toh ye hamara is chapter ka last topic tha, ye aapka kuch chapter ki summary hai jo aapko khud se padh leni hai, theek hai, I hope aapko chapter samajh mein aaya hoga. Agar aapko kuch points hai jo samajh mein nahi aaye ya phir kuch bhi laga ki shayad ye cheez change honi chahiye toh aapko mujhe, aapko mujhe comment section mein bata sakte ho, theek hai. Toh milte hai next lecture mein, mujhe comment section mein bata dena ki aapko kaun sa chahiye agla chapter, wo science ka bhi ho sakta hai social science ka bhi ho sakta hai ya phir wo maths ka bhi ho sakta hai, English ka bhi jo bhi aapko padhna hai just aapko ek baar likh dena hai main uska lecture prepare kar dungi. Okay, toh milte hai next video ke andar, Jai Hind, Jai Bharat.
