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ICSE Class 7 Geography Question 3 of 15

Weather and Climate — Question 4

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Question 4

Write three differences between planetary and periodic winds.

Answer

Three differences between planetary and periodic winds are:

Sl.
No.		Planetary WindsPeriodic Winds
1.Planetary winds blow constantly in a particular direction throughout the year.Periodic winds blow in a definite direction during a particular period of the day or year.
2.Planetary winds originate due to the presence of permanent high pressure and low pressure belts on the earth's surface.Periodic winds are caused due to unequal heating and cooling of the earth's surface.
3.Planetary winds do not have any tendency to reverse their direction periodically.Periodic winds have tendency to reverse their direction periodically.

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