# EQ: How does the Earth move on its axis and around the Sun?

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EQ: How does the Earth move on its axis and around the Sun?
Ch. 9-1 Planetary Motion EQ: How does the Earth move on its axis and around the Sun?

Ch. 9-1 Vocabulary Rotation-the spin of a body (planet) on its axis
Orbit-the path that a body follows as it travels around another body in space Revolution-one complete trip along an orbit Ellipse-an elongated circle Law of universal gravitation-two objects will always be attracted to one another; the product of the masses of two (or more) objects divided by the square of the distance between the objects.

Facts/Information Each planet spins on its on axis.
The half that faces the sun is experiencing light/daytime, while the other half is experiencing darkness/nighttime. “The amount of time a planet takes to complete a single trip around the sun is called a period of revolution.” Earth’s period of revolution is days. Earth’s period of rotation is 23 hours and 56 minutes.

Facts/Information Kepler’s First Law of Motion-planets revolve around the sun in an ellipse. Kepler’s Second Law of Motion-planets move faster when they are close to the sun and slower when they are farther away from the sun. Kepler’s Third Law of Motion-planets that are more distant from the sun take longer to orbit the sun. “If the distance between two objects doubles, the gravitational attraction between them will decrease by a factor of 4.” Inertia is an object’s resistance in speed or direction until an outside force acts on the object.

The Earth moves in an ellipse around the sun and spins on its axis.
Poem The Earth moves in an ellipse around the sun and spins on its axis.

Chapter 9-1 Quiz Each planet spins on its on __________.
Earth’s period of rotation is __________. Half of the earth that faces the sun is experiencing __________, while the other half is experiencing ___________. Earth’s period of revolution is ________ days. “If the distance between two objects __________, the gravitational attraction between them will __________ by a factor of ______.”

Quiz continued… Kepler’s First Law of Motion Inertia
The amount of time a planet takes to complete a single trip around the sun. Planets revolve around the sun in an ellipse. An object’s resistance in speed or direction until an outside force acts on the object. Kepler’s First Law of Motion Inertia Period of revolution

Quiz continued… Planets move faster when they are close to the sun and slower when they are farther away from the sun. Planets that are more distant from the sun take longer to orbit the sun. Kepler’s Third Law of Motion Kepler’s Second Law of Motion

Answer Key Axis 23 hours and 56 minutes
Daylight/daytime; night/nighttime days Doubles; decrease; four C. Period of revolution A. Kepler’s First Law of Motion B. Inertia B. Kepler’s Second Law of Motion A. Kepler’s Third Law of Motion

Works Cited Allen, Katy Z., et al. North Carolina: Holt, Science, & Technology. New York: Holt, Rinehart, & Winston, 2005.

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