🌍 Motions of the Earth – Class 6 Geography Chapter Notes

Earth Season
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Welcome to the complete notes of “Motions of the Earth” – a key chapter in Class 6 Geography (NCERT). In this chapter, we explore how our planet Earth is always moving. These motions – rotation and revolution – shape everything from day and night to seasons, time zones, and climate. Let’s dive deep into understanding these concepts in a clear and student-friendly way.

🌐 Introduction: The Earth is Always Moving

Although we don’t feel it, the Earth is constantly in motion. These motions happen in space and are responsible for natural changes in our environment. There are two major types of movements:

  • Rotation: The spinning of the Earth on its axis.
  • Revolution: The movement of the Earth around the Sun.
Both of these motions are continuous and extremely important in shaping our lives on the planet.

🌀 Rotation – The Earth Spins on Its Axis

The Earth rotates from west to east on an imaginary line called the axis. The axis passes through the North and South Poles and is tilted at an angle of about 66.5° with respect to the Earth's orbit. It takes approximately 24 hours to complete one full rotation. This period is known as a day.

Because of rotation:

  • We experience day and night.
  • The side of the Earth facing the Sun has daylight, while the opposite side experiences darkness or night.
  • This rotation also causes shadows to change position and length during the day.

🔁 Effects of Earth’s Rotation

Rotation impacts several aspects of life on Earth:

  • Creates time zones across the globe.
  • Controls wind direction and ocean currents due to the Coriolis Effect.
  • Helps determine the local time in different regions.
Without rotation, one side of the Earth would remain in constant sunlight while the other would be in darkness — making life almost impossible.

☀️ Revolution – The Earth Orbits the Sun

Apart from rotating on its axis, the Earth also revolves around the Sun. This movement is called revolution. The Earth follows a path called an orbit, which is elliptical in shape. It takes about 365¼ days to complete one revolution.

Because ¼ day is extra, every four years, we add 1 day to the calendar — making that year a leap year with 366 days.

🌱 Effects of Revolution

Earth’s revolution, along with the tilt of its axis, causes:

  • Seasons: Summer, winter, spring, and autumn occur due to the tilt of the axis and revolution.
  • Changes in the length of days and nights: Days are longer in summer and shorter in winter.
  • Varying temperatures: Revolution changes how much sunlight different parts of the Earth receive during the year.

🧭 The Tilt of the Axis and Its Impact

Earth Motion
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The Earth’s axis is tilted at an angle of 23.5° with respect to a line perpendicular to the orbital plane. This tilt is very important in creating the seasons. If there were no tilt, every place on Earth would receive the same amount of sunlight throughout the year. There would be no seasons.

🌎 Equinoxes and Solstices

The way sunlight falls on Earth changes throughout the year due to revolution and tilt. This creates:

  • Summer Solstice (June 21): The Northern Hemisphere receives maximum sunlight; it is summer there.
  • Winter Solstice (December 22): The Southern Hemisphere receives maximum sunlight; it is winter in the north.
  • Spring (Vernal) Equinox (March 21): Day and night are equal worldwide.
  • Autumnal Equinox (September 23): Day and night are again equal; autumn begins in the north.
Equinoxes are days when the Sun is directly above the equator, resulting in equal day and night across the globe.

🕰️ Time and Time Zones

Because the Earth rotates, different parts of the world face the Sun at different times. To make timekeeping manageable, the Earth is divided into 24 time zones — one for each hour. Each zone covers 15° of longitude. In India, we follow Indian Standard Time (IST), which is +5:30 hours ahead of GMT (Greenwich Mean Time).

📌 Important Points to Remember

  • Earth rotates on its axis in about 24 hours — causing day and night.
  • Earth revolves around the Sun in 365¼ days — causing seasons.
  • The Earth’s axis is tilted at 23.5°, which causes varying sunlight and seasons.
  • Rotation is from west to east; it creates the effect of the Sun rising in the east.
  • Leap years adjust the extra ¼ day every four years.
  • Equinoxes and solstices mark key points in the Earth’s movement around the Sun.
Earth tide with moon
Image by brgfx on Freepik

📚 Summary – Motions of the Earth

This chapter explains how the two main motions of Earth — rotation and revolution — affect daily life, seasons, time zones, and the environment. While rotation causes day and night, revolution brings seasonal changes. The tilt of the Earth's axis makes these effects more dramatic, creating diversity in climate and length of day and night across regions.

Understanding these motions helps students connect science with daily experiences like sunrise, sunset, summer, and winter. This knowledge builds a foundation for geography, astronomy, and environmental studies.

💡 Why Is This Chapter Important?

“Motions of the Earth” is not just about remembering definitions. It’s about understanding how we experience time, light, and weather. For students, it lays the groundwork for more advanced topics like climate change, ecosystems, and Earth’s relationship with other celestial bodies.

From every sunrise to every season — it’s all thanks to the amazing motions of the Earth!