Earth's Changing Surface — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
Weathering moves broken rock pieces to a new place far away.
Corrected: Erosion moves broken rock pieces to a new place far away.
In Grade 4 science, weathering breaks rocks apart, but erosion is the process that carries those pieces away.
2. Fix the sentence:
Deposition is when wind or ice breaks rocks into tiny pieces.
Corrected: Weathering is when wind or ice breaks rocks into tiny pieces.
Weathering breaks rocks down; deposition is when the moved sediment finally settles in a new spot.
3. Fix the sentence:
Slow Earth changes like canyons form in only a few days.
Corrected: Slow Earth changes like canyons form over thousands or millions of years.
Grade 4 science teaches that slow processes such as carving canyons take thousands or even millions of years.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. When wind, water, or ice breaks rocks into smaller pieces, the process is called weathering.
Weathering is the slow breakdown of rock by natural forces like rain, ice, and wind.
2. Tiny moved pieces of rock and soil are called sediment.
Sediment is the small bits of weathered rock that water, wind, or ice can carry.
3. When a river drops sediment at its mouth, the process is called deposition.
Deposition happens when moving water or wind slows down and drops the sediment it was carrying.
4. A slow river of ice that scrapes the land as it moves is a glacier.
Glaciers cause weathering and erosion as they slowly grind across rock and carry sediment with them.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Explain the difference between weathering and erosion using your own words.
Sample answer: Weathering is when rocks are broken into smaller pieces by wind, water, or ice. Erosion is when those broken pieces are carried away to a new place. Weathering breaks; erosion moves.
Grade 4 students must clearly separate the breaking step (weathering) from the moving step (erosion).
2. Give one real-life example of deposition you might see outside.
Sample answer: After heavy rain, a stream slows down and drops sand and tiny rocks at the bottom of a hill, building up a small flat area. That dropped sediment is deposition.
Deposition is best understood with concrete examples like deltas, sandbars, or sediment after a flood.