Lecture Notes on Basics of Geography (Grade 11)

Introduction

• Focus on understanding the Earth’s structure and movement.
• Importance of understanding the Earth’s layout before diving into major geography concepts.

Shape and Division of the Earth

• Shape of Earth: Sphere-like, similar to a ball.
• Division:
  • Earth can be divided into two halves called hemispheres.
  • Northern Hemisphere: Upper half.
  • Southern Hemisphere: Lower half.
  • Equator: Line dividing the Earth into two equal halves (hemispheres).

Lines of Latitude

• Definition: Distances measured in degrees north or south from the equator.
• Examples:
  • 30° latitude (north/south of equator)
  • 60° latitude (north/south of equator)
  • 90° latitude (at the poles)
• Regions:
  • Tropics: Areas near the equator.
  • Polar Regions: Areas near 90° latitude, known as the poles.

Earth’s Movements

• Rotation:
  • Earth rotates on its axis.
  • Takes 24 hours, creating a day.
• Revolution:
  • Earth revolves around the sun.
  • Takes 365 days, creating a year.
  • Orbit: Path taken by the Earth around the sun.

Energy Distribution on Earth

• Equator:
  • Receives more direct sunlight, making it hotter.
  • Sun rays are concentrated on a smaller area.
• Poles:
  • Receive sunlight at an oblique angle, hence colder.
• Unequal Energy Distribution:
  • Equator is hotter, poles are colder.
  • Need for energy balance by transferring heat.

Energy Balance

• Mechanisms:
  • Winds: Moving air transfers heat from equator to poles.
  • Ocean Currents: Surface water movement from equator to poles helps balance heat.
• Energy Surplus: Excess heat at the equator.
• Energy Deficit: Less heat at the poles.

Conclusion

• Understanding Earth’s geography is essential in grade 11.
• Future lessons will delve deeper into these concepts.