Earth Science
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High School
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Planet Earth

Planet Earth


Planet Earth

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Lesson 24.1: True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. Earth’s diameter is longer through the poles than through the equator.

_____ 2. Earth’s magnetic field extends several thousands of kilometers into space.

_____ 3. Earth’s axis of rotation passes through the north and south poles.

_____ 4. One complete rotation of Earth requires a little more than 24 hours.

_____ 5. A swinging pendulum appears to change direction because of Earth’s revolution.

_____ 6. Earth’s speed of rotation is greatest at the equator.

_____ 7. Earth has seasons because its orbit around the sun is elliptical.

_____ 8. Earth travels about 150 million kilometers during one revolution.

_____ 9. Earth revolves around the sun at a constant speed.

_____ 10. Earth’s axis is tilted 23 ½ degrees relative to a line drawn perpendicular to the equator.

Lesson 24.1: Critical Reading

Name___________________ Class______________ Date________

Read this passage based on the text and answer the questions that follow.

Earth’s Motions

Imagine a line passing through the center of Earth that goes through both poles. This imaginary line is called an axis. Earth spins around its axis in a movement called rotation. Earth also orbits, or revolves around, the sun. This movement is called revolution.

In 1851, long before Earth could be viewed from space, a French scientist named Léon Foucault determined that Earth rotates. He did this by watching the movement of a pendulum. A pendulum is a heavy weight that swings back and forth on a string. Foucault knew that after a pendulum is set in motion, it will keep moving in the same direction. When Foucault observed his pendulum, it seemed to change direction, so he concluded that Earth must be moving beneath the swinging pendulum.

Earth requires 23 hours, 56 minutes, and 4 seconds to make one complete rotation on its axis. However, because Earth revolves around the sun at the same time that it is rotating, the planet must turn a little bit more to reach the same position relative to the sun. This explains why the length of a day on Earth is actually 24 hours. At the equator, Earth rotates at its maximum speed of about 1,700 km/h. It rotates more slowly at high latitudes, down to a speed of little more than zero km/h at the poles.

For Earth to make one complete revolution around the sun takes 365.24 days. The amount of time Earth—or any planet—takes to revolve around the sun is the definition of a year. The gravitational pull of the sun keeps Earth and the other planets in orbit around it. Like the orbits of the other planets, Earth’s orbit is elliptical rather than circular, so the planet is farther away from the sun at some points in its orbit than others. The closest Earth gets to the sun each year is about 147 million km, which is called perihelion. It occurs on about January 3rd. The farthest Earth gets from the sun each year is about 152 million km, which is called aphelion. It occurs on about July 4th. Earth revolves around the sun at an average speed of about 27 km/s, but it moves more slowly at aphelion and more quickly at perihelion.


  1. Define and describe Earth’s rotation and revolution.
  2. Why did Foucault conclude that Earth rotates?
  3. Why does a day last slightly longer than it takes Earth to make one complete rotation?
  4. Compare and contrast Earth’s perihelion and aphelion.

Lesson 24.1: Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

  1. Earth is similar to the other inner planets in the solar system in its
    1. size.
    2. shape.
    3. composition.
    4. all of the above
  2. When a ship sails away from shore, people watching from shore see the bottom of the ship disappear first. This is because the
    1. atmosphere obscures it.
    2. surface of Earth is curved.
    3. planet is rotating on its axis.
    4. ship sinks deeper into the water.
  3. Earth’s magnetic field resembles the magnetic field of a
    1. bar magnet.
    2. spherical magnet.
    3. horseshoe magnet.
    4. none of the above
  4. Earth’s magnetic field
    1. extends far out into space.
    2. shields the planet from solar radiation.
    3. is small in comparison with the size of Earth.
    4. two of the above
  5. Earth is farthest from the sun during
    1. summer in the Northern Hemisphere.
    2. winter in the Northern Hemisphere.
    3. summer in the Southern Hemisphere.
    4. different seasons from year to year.
  6. Compared with Earth when it is at its aphelion, when the planet is at its perihelion, it is
    1. closer to the sun.
    2. moving more quickly around the sun.
    3. rotating on its axis at a slower speed.
    4. two of the above
  7. Earth has seasons because of changes in
    1. its distance from the sun.
    2. the direction its axis tilts.
    3. the angle at which its axis tilts.
    4. its direction of rotation on its axis.

Lesson 24.1: Matching

Name___________________ Class______________ Date________

Match each definition with the correct term.


_____ 1. place in Earth’s orbit where it is farthest from the sun

_____ 2. spinning of an object around an axis

_____ 3. imaginary line through Earth between the poles

_____ 4. half of a sphere such as Earth

_____ 5. movement of an object in an orbit around another object

_____ 6. place in Earth’s orbit where it is closest to the sun

_____ 7. shape of Earth’s orbit


a. hemisphere

b. ellipse

c. revolution

d. perihelion

e. rotation

f. aphelion

g. axis

Lesson 24.1: Fill in the Blank

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

  1. Earth has a magnetic field because of convection of molten metals in its __________ core.
  2. In 1851, the French scientist Foucault observed a swinging __________ and concluded that Earth rotates.
  3. Earth rotates __________ quickly at its poles than it does at its equator.
  4. The amount of time it takes Earth to revolve around the sun is the definition of a(n) __________.
  5. During summer in the Southern Hemisphere, the __________ tilts toward the sun.
  6. The exact shape of Earth is not a perfect sphere but a(n) __________.
  7. Earth is one of the __________ planets of our solar system.

Lesson 24.1: Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.

Explain two ways that people knew Earth was spherical long before they could observe the shape of Earth from space.