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Revision Notes

Hydrosphere

Kerala Board · Class 9 · Social Science

Quick revision notes for Hydrosphere — Kerala Board Class 9 Social Science. Key concepts, formulas, and definitions for last-minute revision.

44 questions20 flashcards5 concepts

Key Topics to Revise

1

Hydrological Cycle

  • Water is a cyclical renewable resource that continuously moves between oceans, atmosphere, land, and living organisms
  • The hydrological cycle has been operating for billions of years and is essential for all life on Earth
  • Only less than 1% of Earth's water is useful to human beings
2

Water Distribution and Sources

  • 97.2169% of Earth's water is saline ocean water, only 2.7831% is fresh water
  • Of fresh water: 69.56% exists as ice and snow, 30.1% as groundwater, only 0.34% in accessible sources
  • Most accessible fresh water is in lakes, reservoirs, and river systems
3

Oceans and Their Characteristics

  • Five major oceans: Pacific (largest), Atlantic, Indian, Southern/Antarctic, Arctic (smallest)
  • Pacific Ocean separates Asia/Oceania from Americas
  • Atlantic Ocean separates Americas from Europe and Africa
4

Ocean Floor Relief

  • Ocean floor has four main zones: continental shelf, continental slope, deep sea plain, oceanic trenches
  • Continental shelf: 0-200m depth, occupies 7.6% of ocean area, richest in marine resources
  • Continental slope: 200-3000m depth, comprises 15% of ocean area, has submarine canyons

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Full Notes

Key Concepts

The continuous circulation of water between97Pacific (largest)Four main zonesAverage salinity is 35‰ (35 parts

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Frequently Asked Questions

What are the important topics in Hydrosphere for Kerala Board Class 9 Social Science?

Hydrosphere covers several key topics that are frequently asked in Kerala Board Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.

Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.