Solar System — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
The inner planets are Jupiter, Saturn, Uranus, and Neptune because they are rocky.
Corrected: The inner planets are Mercury, Venus, Earth, and Mars because they are rocky.
The corrected sentence is: "The inner planets are Mercury, Venus, Earth, and Mars because they are rocky.". The original sentence "The inner planets are Jupiter, Saturn, Uranus, and Neptune because they are rocky." contained an error that needed to be fixed.
2. Fix the sentence:
Rotation means one complete trip around the Sun which takes Earth one year.
Corrected: Revolution means one complete trip around the Sun which takes Earth one year.
The corrected sentence is: "Revolution means one complete trip around the Sun which takes Earth one year.". The original sentence "Rotation means one complete trip around the Sun which takes Earth one year." contained an error that needed to be fixed.
3. Fix the sentence:
The outer planets are smaller than the inner planets and have no rings.
Corrected: The outer planets are larger than the inner planets and all have rings.
The corrected sentence is: "The outer planets are larger than the inner planets and all have rings.". The original sentence "The outer planets are smaller than the inner planets and have no rings." 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 four inner planets are also called terrestrial planets because they have rocky surfaces.
Terrestrial means Earth-like. The four inner planets (Mercury, Venus, Earth, Mars) are rocky and solid.
2. One full spin of Earth on its axis is called a rotation and takes about 24 hours.
Rotation is Earth spinning on its axis. One rotation = one day (approximately 24 hours).
3. Jupiter and Saturn are classified as gas giants because they are mostly made of gas.
Jupiter and Saturn are gas giants — mostly hydrogen and helium with no solid surface.
4. Uranus and Neptune are called ice giants because they contain frozen water and ammonia.
Uranus and Neptune are ice giants — they contain water, ammonia, and methane ices beneath their atmospheres.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Name two differences between the inner planets and the outer planets.
Sample answer: Inner planets are small and rocky with few or no moons, while outer planets are large and made of gas or ice with many moons and ring systems.
Inner: Mercury, Venus, Earth, Mars — rocky, smaller, closer to Sun. Outer: Jupiter, Saturn, Uranus, Neptune — huge, gaseous/icy, many moons.
2. Explain the difference between rotation and revolution using Earth as an example.
Sample answer: Rotation is Earth spinning on its axis once every 24 hours, which gives us day and night. Revolution is Earth traveling around the Sun once every 365 days, which gives us a year.
Rotation = spin on axis (day/night). Revolution = orbit around Sun (year).