Science

• Rotation


  The spinning of Earth on its axis
• Earth's axis


  • An imaginary line that passes through the center of Earth, from the North Pole to the South Pole
  • Tilted at 23.5 degrees from the vertical plane
• Earth rotates from west to east
• The direction of Earth's rotation is counterclockwise when viewed from over the North Pole and clockwise when viewed from under the South Pole
• How the Earth formed

  1. A cloud made up of gas and dust collapsed in outer space

  2. As it collapsed, it spun at an increasing rate while it flattened into a disk

  3. The sun then formed at the center

  4. Gas and dust collided and stuck together to form planets, asteroids, moons, and comets

  5. All space objects rotated toward the same direction because they formed from the same disk

  6. Objects keep spinning due to inertia
• Complete rotation


  The amount of time it takes Earth to turn around once on its axis, which is approximately 24 hours
• One complete rotation of Earth is considered one day
• Earth's rotation slows slightly with time, resulting in slightly shorter days over millions of years
• Earth's motion


  Spins on its axis, revolves around the sun in an elliptical or oval-shaped path
• Earth's revolution around the sun

  Speed of 108,000 kph, completes in 365 days
• One complete revolution is equal to one year
• Leap year


  Fourth year with 366 days, February has 29 days instead of 28
• Earth's position and orientation relative to the sun changes from day to day
• Earth moves closer to or farther away from the sun
• Different parts of Earth face the sun at different times
• Effects of Earth's revolution

  • Change in seasons
  • Lengths of days and nights
• Changing seasons


  1. March 21

  2. June 21

  3. September 23

  4. December 12
• Seasons are periods of the year characterized by changes in weather, particularly temperature and lengths of days and nights
• Seasons


  • Spring
  • Summer
  • Autumn
  • Winter