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.
Key Topics to Revise
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
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
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
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 NotesKey Concepts
Get detailed revision notes for Our Earth
Super Tutor gives you interactive content for every chapter of Kerala Board Class 9 Social Science — summaries, quizzes, flashcards, and more.
Try Super Tutor — It's FreeFrequently 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?
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
- Kerala Board of Public Examinations — keralapareekshabhavan.in
- National Education Policy 2020 — education.gov.in
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More Resources for Our Earth
Important Questions
Practice with board exam-style questions
Syllabus
What topics to cover
Study Plan
Step-by-step plan to ace this chapter
Flashcards
Quick-fire cards for active recall
Formula Sheet
All formulas in one place
Chapter Summary
Understand the chapter at a glance
Practice Quiz
Test yourself with a quick quiz
Concept Maps
See how topics connect visually