Earth's Changing Surface — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. The Grand Canyon was carved over millions of years mostly by the Colorado River.
Grade 4 NGSS uses the Grand Canyon as a classic example of long-term river erosion.
2. The Himalayas formed when two of Earth's huge plates collided and pushed up.
Grade 4 students learn tectonic plate collisions build mountain ranges like the Himalayas.
3. The Hawaiian Islands rose from the ocean because of underwater volcanoes erupting.
Grade 4 NGSS includes volcanic island formation as a constructive Earth process.
4. Old Faithful in Yellowstone is a famous geyser that shoots hot water into the air.
Grade 4 students learn geysers are surface features showing Earth's inner heat.
5. When the Colorado River carries sand and pebbles away, the process is called erosion.
Grade 4 NGSS distinguishes erosion (moving sediment) from weathering (breaking rock).
6. Earthquakes near the Himalayas happen because plates slide along a fault.
Grade 4 students learn faults are zones where plate motion releases earthquakes.
7. The slow movement of huge slabs of Earth's crust is called tectonic activity.
Grade 4 NGSS introduces tectonic activity to explain mountains, faults, and volcanoes.
8. Sand dropped by a river at its mouth builds a flat landform called a delta.
Grade 4 students connect deposition by rivers to delta formation.
9. Lava that cools and hardens above the ocean creates new land over time.
Grade 4 NGSS shows volcanoes as constructive forces that build new land.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Grand Canyon
→ Carved by long-term river erosion
Carved by long-term river erosion
Himalayas
→ Built by colliding tectonic plates
Built by colliding tectonic plates
Hawaiian Islands
→ Formed by underwater volcanoes
Formed by underwater volcanoes
Old Faithful
→ Geyser powered by underground heat
Geyser powered by underground heat
Grade 4 NGSS 4-ESS2 students link real landforms to Earth processes that shaped them.