Skip to main content
Chapter 1 of 22
Revision Notes

Our Earth

Kerala Board · Class 9 · Social Science

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

44 questions22 flashcards5 concepts

Interactive on Super Tutor

Studying Our Earth? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for revision notes and more.

1,000+ Class 9 students started this chapter today

Key Topics to Revise

1

Our Universe, Sun and Earth

  • Earth is part of a vast universe that started 13.7 billion years ago with the Big Bang theory
  • Initially, people believed in Geocentric theory (Ptolemy) - Earth at center of universe
  • Later, Heliocentric theory (Copernicus) proved Sun is at center of solar system
2

Earth as a Planetary Body

  • Earth rotates on its axis and revolves around Sun in 365¼ days (one year)
  • Earth's orbit is nearly circular, not perfectly circular
  • Distance from Sun: closest point 147 million km, farthest 152 million km
3

Evolution and Formation of Earth

  • Earth formed 4.5 billion years ago from swirling dust and clouds
  • Initially Earth was molten (hot liquid form) due to constant bombardment
  • Heavier substances sank to form core, lighter substances rose to form crust
4

Internal Structure of Earth

  • Earth has three main layers: Crust, Mantle, and Core
  • Crust: 0-100 km depth, consists of various rocks, where we live
  • Mantle: 100-2,900 km depth, made of silicates, upper part is pliable

Get complete notes with diagrams and examples

Full Notes

Key Concepts

Earth formed about 4Earth has three main layersAlfred Wegener proposed that all continentsLatitudes are horizontal circles parallelEarth is divided into 24 time

Frequently Asked Questions

What are the important topics in Our Earth for Kerala Board Class 9 Social Science?
Our Earth 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.
How to score full marks in Our Earth — Kerala Board Class 9 Social Science?
Understand the core concepts first, then work through the 44 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

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

For serious students

Get the full Our Earth chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for Kerala Board Class 9 Social Science.