Inner Planets
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Printed: August 29, 2014
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C HAPTER
Chapter 1. Inner Planets
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Inner Planets
Lesson 25.2: True or False
Name___________________ Class______________ Date________
Write true if the statement is true or false if the statement is false.
_____ 1. Venus is the only inner planet that has been explored by rovers.
_____ 2. All of the inner planets have iron cores.
_____ 3. Mercury’s surface is covered with volcanoes.
_____ 4. From Earth, Venus appears very bright because its surface is so hot that it glows.
_____ 5. Clouds on Venus contain carbon dioxide, sulfur dioxide, and sulfuric acid.
_____ 6. Venus has more volcanoes than any other planet in the solar system.
_____ 7. Volcanic activity on Venus is caused by plate tectonics.
_____ 8. Mars has been studied more thoroughly than any other planet except Earth.
_____ 9. Mars appears to be red in color because of iron oxide in its soil.
_____ 10. Water cannot stay in the liquid state on Mars because its temperature is too low.
Lesson 25.2: Critical Reading
Name___________________ Class______________ Date________
Read this passage based on the text and answer the questions that follow.
Venus
Of all the planets in our solar system, Venus is most similar to Earth in size and density. Venus is also our nearest
neighbor. In addition, Venus’ interior structure is similar to Earth’s, with a large iron core and a silicate mantle. But
the resemblance between the two inner planets ends there.
One way that Venus differs from Earth—and from all of the other planets in the solar system—is its direction of
rotation. Venus rotates in a direction opposite to the direction that it orbits the sun, whereas the rest of the planets
rotate in the same direction that they orbit the sun. Venus’ rotation is also extremely slow, with just one rotation
every 243 days. This is longer than the 224 days it takes Venus to orbit the sun, so a day on Venus is longer than a
year.
Like Earth, Venus has an atmosphere, but the atmosphere is very different from Earth’s atmosphere. Venus’
atmosphere consists mostly of carbon dioxide with some sulfur dioxide and sulfuric acid, which is highly corrosive.
Because carbon dioxide is a greenhouse gas, Venus’ atmosphere traps heat from the sun and creates a powerful
greenhouse effect. Although Venus is farther from the sun than Mercury, the greenhouse effect makes Venus hotter
than Mercury. In fact, Venus is the hottest planet in the solar system. Temperatures at the surface reach 465 degrees
Celsius, which is hot enough to melt lead! The atmosphere of Venus is also extremely thick. Because of the thickness
of the atmosphere, the atmospheric pressure on the planet’s surface is 90 times greater than the atmospheric pressure
on Earth’s surface.
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Like Earth, Venus has many volcanoes. In fact, the surface of the planet is covered by large areas of volcanoes
surrounded by plains of lava, and some of the volcanoes may be active. On Earth, volcanoes erupt along tectonic
plate boundaries. On Venus, which lacks tectonic plates, heat builds up inside the planet and has no way to escape.
The heat keeps building up until it finally destroys the crust and allows magma to erupt onto the surface.
Questions
1.
2.
3.
4.
In what ways does Venus resemble Earth?
How is Venus’ rotation unique among all the planets in the solar system?
Explain how Venus’ atmosphere compares with that of Earth.
Describe volcanic activity on Venus.
Lesson 25.2: Multiple Choice
Name___________________ Class______________ Date________
Circle the letter of the correct choice.
1. The terrestrial planets include
a.
b.
c.
d.
Mars.
Venus.
Mercury.
all of the above
2. All of the inner planets
a.
b.
c.
d.
have one or more moons.
are made of igneous rock.
have been geologically active.
two of the above
3. Compared with the outer planets, the inner planets have
a.
b.
c.
d.
slower rotations.
longer orbits.
more rings.
more moons.
4. Temperatures vary widely on Mercury because it has
a.
b.
c.
d.
almost no atmosphere.
water on the surface.
rapid rotation.
a thin crust.
5. Venus is very similar to Earth in terms of its
a.
b.
c.
d.
size.
density.
atmospheric pressure.
two of the above
6. On which planet is a year shorter than a day?
a. Mercury
b. Venus
c. Earth
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Chapter 1. Inner Planets
d. Mars
7. Compared with Earth, Mars is
a.
b.
c.
d.
smaller.
colder.
drier.
all of the above
Lesson 25.2: Matching
Name___________________ Class______________ Date________
Match each definition with the correct term.
Definitions
_____ 1. any of the four planets closest to the sun
_____ 2. smallest planet in the solar system
_____ 3. feature shared by all of the inner planets
_____ 4. any planet farther from the sun than Mars
_____ 5. planet with the highest temperatures
_____ 6. feature found only on Earth and Mars
_____ 7. inner planet that has two moons
Terms
a. ice cap
b. Mars
c. Mercury
d. outer planet
e. iron core
f. Venus
g. inner planet
Lesson 25.2: Fill in the Blank
Name___________________ Class______________ Date________
Fill in the blank with the appropriate term.
1.
2.
3.
4.
5.
6.
The inner planets are also called __________ planets because they are similar to Earth.
The only inner planet that has a large moon is __________.
About 42 percent of Mercury’s volume consists of its __________.
The planet that is Earth’s closest neighbor is __________.
The planet with the largest mountain in the solar system is __________.
The only planet that rotates in a direction opposite to the direction it revolves is __________.
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7. The moons of Mars are thought be captured __________.
Lesson 25.2: Critical Writing
Name___________________ Class______________ Date________
Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.
Of all the inner planets besides Earth, Mars is the most likely ever to have had life. Explain why.
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