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ICSE Class 7 Geography Question 6 of 15

Weather and Climate — Question 7

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Question 7

What is rain? Classify rainfall and explain convectional rainfall with a labelled diagram.

Answer

When precipitation occurs in the form of water drops, it is called rain and it is the most important form of precipitation. Rainfall can be classified into three types. They are:

  1. Orographic rainfall
  2. Convectional rainfall
  3. Cyclonic rainfall

Convectional rainfall — When air comes in contact with the hot surface of the earth, it gets heated, becomes light and rises in form of air current. After the warm air current reaches the upper layers of the atmosphere, it expands and loses heat. This leads to condensation and the formation of cumulus clouds. These clouds give sudden and heavy rainfall accompanied by thunder and lightning. Convectional rainfall occurs every day in the equatorial region.

What is rain? Classify rainfall and explain convectional rainfall with a labelled diagram. Around the World Geography Solutions ICSE Class 7.

ICSE Class VII Geography — Chapter 2: Weather and Climate

Bright Tutorials | ICSE Class VII | Geography | Chapter 2

Weather vs Climate — What is the Difference?

Weather is the day-to-day condition of the atmosphere at a particular place and time — it changes rapidly. Climate is the average weather conditions of a place recorded over 30 or more years — it changes very slowly. For example, "It is raining today" describes weather, while "Mumbai gets heavy monsoon rain in July-August" describes climate.

Elements of Weather and Their Instruments

Weather has six main elements, each measured by a specific instrument: temperature (thermometer), atmospheric pressure (barometer), humidity (hygrometer), rainfall (rain gauge), wind speed (anemometer), and wind direction (wind vane). Understanding these elements and instruments is essential for ICSE Geography.

Factors Affecting Climate

Six main factors determine the climate of a place: Latitude (nearer the equator = hotter), Altitude (temperature drops 6.5°C per 1,000 m — the Normal Lapse Rate), Distance from the sea (coastal areas have moderate climate), Ocean currents (warm currents raise temperature), Prevailing winds (sea winds bring rain), and Mountain barriers (windward side gets rain, leeward side is the rain shadow).

Climate Zones and Types of Rainfall

The world is divided into three climate zones: Torrid (0°-23.5°, hot), Temperate (23.5°-66.5°, moderate), and Frigid (66.5°-90°, extremely cold). There are three types of rainfall: convectional (heated air rises, common near equator), orographic (wind forced up mountains, windward rain), and cyclonic (warm and cold air masses meet, common in temperate regions).

Key Takeaways for ICSE Class VII Students

  • Weather = short-term, Climate = long-term average
  • Normal Lapse Rate: temperature drops 6.5°C for every 1,000 m rise
  • Learn to draw diagrams for all three types of rainfall
  • Know which instrument measures which element
  • Understand why coastal cities like Mumbai have moderate climate while inland cities like Nagpur have extreme climate