Science Review

• Rotation

  1. The Earth is spinning on its axis at a regular and steady rate once every 24 hours

  2. The direction of Earth's rotation is from west to east or counterclockwise
• The Sun appears to rise in the east, travel across the sky, and set in the west


  The movement of the Earth on its axis is called rotation
• Rotation


  The movement of the Earth on its axis
• Day and Night

  The rotation of the Earth causes day and night
• The Sun is the closest star to Earth
• The apparent movement of the Sun

  Is due to the direction of Earth's rotation
• Revolution

  1. The Earth revolves around the Sun in a counterclockwise direction

  2. It takes the Earth a year, or 365 1/4 days to revolve around the Sun
• Revolution

  The path of a something(earth) around something(sun)
• To complete one revolution, the Earth has to travel 365 days
• We base our calendar on a year of 365 days
• Every four years, one day is added to the month of February, so the number of days become 366
• Leap year


  A leap year has 366 days
• The Effects of Earth's Revolution: Four Seasons

  1. Different parts of the Earth receive different amounts of sunlight at different times of the year

  2. As the Earth moves around the Sun, the Earth's axis is always tilted in the same direction throughout its orbit
• The Earth tilts at 23 degrees
• It takes 365 1/4 days for Earth to complete one revolution around the Sun
• There are 365 1/4 days in a natural year.
• There are 366 days in a leap year.
• There are 365 1/4 days in a natural year but 366 on a leap year
• One day is added in February in a leap year.
• Every four years, a leap year occurs.
• To complete one revolution, the Earth needs to complete a whole orbit around the sun.