Solar System — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
Jupiter is the smallest planet in our solar system and is made of solid rock.
Corrected: Jupiter is the largest planet in our solar system and is made mostly of gas.
The corrected sentence is: "Jupiter is the largest planet in our solar system and is made mostly of gas.". The original sentence "Jupiter is the smallest planet in our solar system and is made of solid rock." contained an error that needed to be fixed.
2. Fix the sentence:
Venus is the coldest planet because it is the second planet from the Sun.
Corrected: Venus is the hottest planet because its thick atmosphere traps heat like a greenhouse.
The corrected sentence is: "Venus is the hottest planet because its thick atmosphere traps heat like a greenhouse.". The original sentence "Venus is the coldest planet because it is the second planet from the Sun." contained an error that needed to be fixed.
3. Fix the sentence:
Saturn is famous for its large red spot which is a giant storm.
Corrected: Saturn is famous for its ring system which is made of ice and rock.
The corrected sentence is: "Saturn is famous for its ring system which is made of ice and rock.". The original sentence "Saturn is famous for its large red spot which is a giant storm." contained an error that needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. The planet closest to the Sun is Mercury.
Mercury is the innermost planet, orbiting closest to the Sun at about 36 million miles away.
2. Earth is the only planet known to have liquid water on its surface.
Liquid water on Earth's surface is a key factor that makes life possible here.
3. Mars is often called the red planet because of iron oxide on its surface.
Iron oxide (rust) covers much of Mars's surface, giving it a reddish appearance visible from Earth.
4. The mnemonic My Very Excellent Mother Just Served Us Nachos helps remember planet order.
My=Mercury, Very=Venus, Excellent=Earth, Mother=Mars, Just=Jupiter, Served=Saturn, Us=Uranus, Nachos=Neptune.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. List the eight planets in order from the Sun.
Sample answer: The eight planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Inner planets: Mercury, Venus, Earth, Mars. Outer planets: Jupiter, Saturn, Uranus, Neptune.
2. Why is Mercury the planet with the biggest temperature swings even though it is closest to the Sun?
Sample answer: Mercury has no atmosphere to trap heat. During the day the surface gets extremely hot, but at night the heat escapes into space and it becomes extremely cold.
Atmosphere acts as a thermal blanket. Without one, extreme day-night temperature differences occur.