Vaayudaab, Hawa aur Aardrata

Class 7 Social Science · Chapter 2: Mausam ko Samajhna · NCERT Exploring Society: India and Beyond section 2.3

Seekho

Aandhi se pehle hawa "bhaari" lag sakti. Vaayudaab hawa ke vazan ka dabaav. Ye samudra tal par zyaada aur pahaadon par kam, jahaan hawa patli aur kam oxygen, to parvataarohi haanpte aur anukoolan ke liye rukte. Barometer ise millibar (mb) mein naapta: tat par lagbhag 1013 mb, par Ladakh ke Khardung La par sirf lagbhag 650 mb, jahaan sainik 5600 m se oopar tainaat. 1000 mb se neeche paathyaank avdaab ka sanket, jo toofaan ya chakravaat ban sakta.

Hawa zyaada daab se kam daab ki or chalti hawa. Paailat, naavik aur kisaan iski chaal aur disha dekhte; tez hawa mitti bhi jaldi sukhaati. Pavan suchak (wind vane) batata hawa kis disha se aa rahi (hawaai adde par wind sock), aur anemometer ke ghoomte cup iski chaal km/h mein naapte: jitna tez ghoomein, utni tez hawa.

Aardrata hawa mein jal-vaashp ki maatra, hygrometer se saapeksh aardrata ke roop mein naapi: 100% matlab hawa santripta. Sookha mausam lagbhag 20–40%, nam 60–80%. Jab barabar garam dinon mein Zoya ka tatiya shehar 84% aur Kabir ka andaruni shehar 52%, Kabir ke kapde jaldi sookhte aur Zoya ko zyaada paseena, kyunki nam hawa mein paani dheere udta. Sangrahaalay aur khaadya kaarkhaane aardrata dhyaan se niyantrit karte.

Explore: yantra milaao.

1. Har sanket sort karo.

Yaad rakho

• Daab oonchaai ke saath girta; barometer mb mein padhta, 1000 mb se neeche avdaab.
• Hawa zyaada se kam daab ki or (pavan suchak, anemometer); aardrata hygrometer se.

Quick check

Hawa hamesha kahaan se kahaan?

1. zyaada daab se kam daab
2. kam se zyaada daab
3. thandi jagah se Sooraj
4. sirf samudra se pahaad

Socho

Parvataarohi seedhe choti tak jaane ki jagah charanon mein kyun chadhte?

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.