Lecture on Earth's Rotation and Revolution

Introduction

• The video presentation covers the two main motions of Earth: rotation and revolution.

Earth's Rotation

• Rotation is the movement of the Earth on its axis.
  • The axis is an imaginary line running from the North Pole to the South Pole.
  • Earth rotates from west to east.
  • Appears clockwise when viewed from above the North Pole and counterclockwise from above the South Pole.
  • Completes one rotation every 24 hours (1 day).
  • This motion causes day and night on Earth.

Earth's Revolution

• Revolution is the movement of Earth around the Sun.
  • The path followed is called an orbit.
  • Earth's orbit is slightly elliptical, not a perfect circle.
  • Distance from the Sun varies during orbit:
    • Closest: at perihelion (~147 million km).
    • Farthest: at aphelion (~152 million km).
  • Takes 365 and 1/4 days for one revolution (1 year).
  • Calendar year is 365 days; every four years, an extra day is added (Leap year).

Quiz Questions

1. Rotation Time: How many hours for one complete rotation?
   • a) 12 hours, b) 24 hours, c) 6 hours, d) 18 hours
2. Revolution Time: How many days for one complete revolution?
   • a) 340 days, b) 365 and 1/4 days, c) 390 days, d) 365 and 1/2 days
3. Revolution Direction: How does Earth revolve around the Sun?
   • a) Clockwise, b) Counterclockwise, c) Circular, d) Any direction
4. Rotation and Revolution: Does Earth rotate on its axis while revolving?
   • a) Yes, b) No, c) Maybe, d) Perhaps
5. Observation Tool: What to use to observe Earth's revolution?
   • a) Model of the solar system, b) Model of Earth's layers, c) Model of Earth revolving, d) None

Vocabulary

1. Revolution: Earth's motion around the Sun.
2. Axis: Imaginary line describing Earth's tilt.
3. Orbit: Earth's path around the Sun.
4. Perihelion: Earth's orbit closest to the Sun.
5. Aphelion: Earth's orbit farthest from the Sun.

Performance Task

• Complete the table:
  • Rotation:
    • Illustration: Diagram showing Earth's spin on its axis.
    • Time to complete motion: 24 hours.
    • Effect: Causes day and night.
  • Revolution:
    • Illustration: Diagram showing Earth's orbit around the Sun.
    • Time to complete motion: 365 and 1/4 days.
    • Effect: Causes seasons.

Conclusion

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