NCERT Geography Class 7 Chapter 6

Weather is the environmental conditions at a particular place at a given time whereas climate is the subtotal of weather conditions in a particular area over a period of 31 years. Sun radiates heat and energy in the form of solar radiation. The amount of solar radiation received by earth is Insolation whereas the amount reflected back by the earth during the night is terrestrial radiation. Temperature is measured by a thermometer and the most scales used to measure it are celsius and Fahrenheit. On the basis of the amount of heat received into 3 heat zones- Torrid(receives maximum insolation; hottest part of the earth), Temperate(moderate insolation; moderate temperature), and Frigid(highly oblique sun’s rays; coldest part of the earth). Weight exerted by the atmosphere is called atmospheric pressure; measure with the help of a Barometer and Millibar(mb) is its unit. Air moves from a high-pressure region to a low-pressure region. Air that moves horizontally is Wind; the vertical movement creates an air column. Sir Francis Beaufort devised a 13 level scale known as the Beaufort scale to represent the strength of the wind. The direction of the wind is found by a wind vane while speed is measured by Anemometer. Winds are broadly classified into- planetary winds(trade winds, westerlies & polar winds); periodic winds(land & Seabreeze, mountain & valley breeze); and local winds(loo, chinook, foehn). Moisture refers to the water content that varies from place to place and from time to time. There are 4 forms of moisture- Evaporation(water vapor); Humidity(absolute humidity, relative humidity); Condensation(clouds- cirrus, stratus, cumulus); Precipitation(rain, drizzle, snow and hailstones). Rainfall is the most important form of precipitation, it is of 3 types- Convectional rainfall; Orographic rainfall; and Cyclonic rainfall. For further details please refer to my YouTube video- https://youtu.be/HzxhVUmVL70