Earth's Layers — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Earth's crust is divided into large pieces called tectonic plates.
Tectonic plates are large sections of Earth's crust that float on the mantle and slowly move.
2. Convection currents in the mantle cause tectonic plates to move slowly over time.
Hot rock rises, cools, and sinks in the mantle, creating convection currents that drag plates.
3. Volcanoes and earthquakes happen most often at plate boundaries.
Where plates meet, collide, separate, or slide past each other, geological activity is most intense.
4. The movement of liquid iron in the outer core creates Earth's magnetic field.
Flowing liquid iron acts like a dynamo, generating the magnetic field that surrounds Earth.
5. Earth's magnetic field protects living things from harmful solar radiation.
The magnetosphere deflects charged particles from the Sun that would otherwise strip away the atmosphere.
6. When tectonic plates push together, they can form mountain ranges over millions of years.
Colliding continental plates push up rock layers to form mountain ranges like the Himalayas.
7. Hot melted rock that rises from the mantle to the surface is called magma.
Magma is molten rock within Earth. Once it reaches the surface through a volcano, it is called lava.
8. An earthquake occurs when tectonic plates suddenly shift and release energy.
Stress builds up along plate boundaries. When plates suddenly move, they release energy as seismic waves.
9. The Ring of Fire is an area around the Pacific Ocean with many volcanoes and earthquakes.
The Ring of Fire follows the edges of the Pacific Plate, where multiple plates meet.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Mantle convection currents
→ Drive tectonic plates to move across Earth's surface
Where most volcanoes and earthquakes occur
Outer core movement
→ Creates Earth's magnetic field that shields us from solar wind
Drive tectonic plates to move across Earth's surface
Plate boundaries
→ Where most volcanoes and earthquakes occur
Large puzzle-like pieces that make up Earth's outer shell
Crust plates
→ Large puzzle-like pieces that make up Earth's outer shell
Creates Earth's magnetic field that shields us from solar wind
Mantle convection=drive plates(idx1); Outer core movement=creates magnetic field(idx3); Plate boundaries=volcanoes/earthquakes(idx0); Crust plates=large puzzle pieces(idx2)