Lesson Plan - Get It!
How does the Earth move in our solar system? Is it able to move wherever it wants?
When discussing the movement of the Earth, there are two important terms to know: rotation and revolution.
Rotation describes the way the Earth moves on its axis, an imaginary line that goes through the center of the planet.
Revolution describes the circular motion the Earth takes around the sun.
You can model each of these movements using a large ball such as basketball, kickball, or soccer ball. Try to spin the ball on the tip of your pointer finger. Does this movement model a rotation or a revolution? Discuss your response with a teacher or parent.
If you answered rotation, you are correct.
Next, hold the ball with both of your hands. Move the ball in a circular motion by moving your arms. Does this movement model a rotation or a revolution? Discuss with a teacher or parent. This movement is modeling a revolution.
The Earth is constantly rotating on its axis and revolving around the sun. Our calendars and measurement of time were created with these movements in mind. It takes the Earth 24 hours to complete one rotation (spinning on its axis), thus equaling a day. It takes the Earth about 365.25 days to complete one revolution (to move full circle) around the sun.
Have you noticed that every four years, February has an extra day? February 29 is known as Leap Day. Leap Days were created to account for the remaining time that is left over when the Earth makes a revolution. In other words, it takes four years for that remaining time to equal one day.
So, what exactly causes the Earth to continuously revolve around the sun?
The sun is the heaviest object in our solar system. It is more than 300,000 times heavier than the Earth. Most objects in space exert a gravitational pull. Since the sun is the largest object in our solar system, its gravitational pull is the greatest. Therefore, other objects in the solar system revolve around the sun.
Continue learning about Earth's rotation and revolution by watching Crash Course Kid's Earth's Rotation & Revolution: Crash Course Kids 8.1:
Re-read the questions found at the beginning of this lesson. Discuss your answers with a teacher or parent.