Class 7 Social Science Chapter 2: Understanding the Weather (Hinglish Notes)

Ye chapter kis baare mein hai?

Sardi ki subah tum kaanpte ho aur sweater pehnte ho; garmi mein halke kapde chunte ho. Tumhara shareer weather mehsoos kar raha hai. Ye chapter us ehsaas ko sankhyaon mein badalta hai. Iske do bade sawaal hain: apne aas-paas ke weather ko kaise naapein aur us pe nazar rakhein, aur weather ke andaaze bhaari baarish, toofaan, sookhe aur heat wave ke liye taiyaar hone mein kaise madad karte hain?

Weather aur atmosphere

Weather kisi khaas samay aur jagah pe atmosphere ki halat hai. Atmosphere Earth ke chaaron or gaison ki parat hai, jise hum hawa kehte hain. Cake ki tarah iski kai parten hain. Sabse neeche troposphere hai, jahan paudhe, jaanwar aur insaan rehte hain aur jahan lagbhag saara weather banta hai. Dhruvon pe, jahan thandi hawa sikudti hai, ye lagbhag 6 km moti hai, aur tropics pe, jahan garam hawa phailti hai, lagbhag 18 km.

Weather ke paanch elements

Garam, baarish waala, hawadaar aur umas bhara jaise shabd weather ke paanch elements batate hain: temperature (hawa kitni garam ya thandi hai), precipitation (baarish, barf, sleet ya ole), atmospheric pressure (upar ki hawa ka wazan), hawa (chalti hawa, uski speed aur disha) aur humidity (hawa mein bhaap). “Thand hai” ka matlab Chennai aur Kashmir mein alag hota hai, isliye weather batane ke liye sabki maani hui units chahiye. Aur padho weather ke elements mein.

Nature ke ishaare

Instruments se bahut pehle log Nature ke ishaare padhte the. Cheentiyon ka ande oonchi jagah le jaana, mendhakon ka zor se tarrana, panchhiyon ka neeche udna aur gilahriyon ka meve jama karna aane waali baarish ya toofaan ka ishaara maana jaata tha, aur cheed ke shanku (pine cones) nam hawa mein band aur sookhi hawa mein khul jaate hain. India ke kai hisson mein ye paaramparik gyaan aaj bhi use hota hai, khaas kar monsoon kab aayega ye andaaza lagaane mein.

Weather naapna

Aaj meteorologists, yaani weather ka adhyayan karne waale, instruments use karte hain. Thermometer temperature naapta hai, aksar din ka maximum aur minimum bhi; inse range (maximum − minimum) aur mean daily temperature ((maximum + minimum) ÷ 2) nikalte hain. Rain gauge baarish ko jama paani ki gehraai se naapta hai: 5 mm paani matlab 5 mm baarish. Barometer pressure millibar mein naapta hai, tat pe lagbhag 1013 mb. Oonchaai pe pressure ghatta hai, isliye upar saans phoolti hai; Ladakh ke Khardung La pe, samudra tal se 5,600 m se zyaada oonchaai pe, ye lagbhag 650 mb hai. Tat ke paas lagbhag 1000 mb se neeche achaanak giraavat depression hai, jo toofaan ya cyclone ban sakta hai.

Hawa high se low pressure ki taraf chalti hai. Wind vane ya windsock uski disha batata hai, aur ghoomte cups waala anemometer uski speed km/h mein. Hygrometer relative humidity naapta hai: 20–40 percent sookha mausam hai aur 60–80 percent nam. Dekho weather ke instruments.

Weather stations

Weather station in saare instruments ko ek jagah rakhta hai, aur readings tay samay pe li jaati hain. Automated Weather Station (AWS) data khud record karke bhejta hai. 2023 mein National Disaster Management Authority ne Sikkim ki ek glacial jheel pe, samudra tal se 4,800 m se zyaada oonchaai pe, AWS lagaaya taaki wahan ke weather ki jaankari pehle mil sake.

Weather ka andaaza

Meteorologists lambe samay ka jama data padhkar vaigyanik tareekon se weather ka forecast karte hain. Climate change ki wajah se sookha, baadh aur cyclone zyaada hone lage hain, isliye ye andaaze aur zaroori ho gaye hain. 1875 mein bana India Meteorological Department (IMD) chaar rangon mein warning map jaari karta hai: hara matlab koi chetaavni nahi, peela matlab nazar rakho, orange matlab taiyaar raho aur laal matlab kadam uthao. Chetaavni se sarkaar taiyaari kar paati hai, toofaan se pehle machhuaare kinaare pe rukte hain aur cyclone se pehle tat se logon ko hataaya ja sakta hai. Padho weather forecast kaise hota hai.

Aage badhne se pehle

Paanchon elements milkar kisi jagah ka weather batate hain, aur instruments se hum unpe nazar rakhte aur andaaza lagaate hain. Kabhi ek element haavi hota hai: July mein baarish, May aur December mein temperature, cyclone aane pe pressure, aur jab north India mein garam, dhool bhari loo chalti hai ya jangal ki aag phailti hai tab hawa. Weather climate se juda hai, jo agle chapter ka vishay hai. Chapter ke har sawaal ka jawab Chapter 2 ke NCERT solutions mein hai.