Plate Tectonics Forces Worksheet

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Plate tectonics illustration showing tectonic plates

🌍 Part 1: Key Concepts — Multiple Choice

Circle the best answer for each question.

1. What is slab pull?

Hot magma rising from the mantle and pushing plates apart

The weight of a dense, sinking oceanic plate pulling the rest of the plate along with it

Two plates colliding and folding upward to form mountains

The cooling of the ocean floor causing plates to stop moving

2. Ridge push occurs at:

Subduction zones where plates sink into the mantle

Mid-ocean ridges where new crust is formed and plates are pushed apart

Continental collision zones where mountains form

Transform boundaries where plates slide past each other

3. Convection currents in the mantle are driven by:

The gravitational pull of the Moon

Wind and weather patterns on Earth's surface

Heat from Earth's core causing hot material to rise and cool material to sink

The rotation of Earth on its axis

4. Which of the following geological events are linked to tectonic plate movement? (Tick ALL that apply)

Earthquakes

Volcanic eruptions

Mountain building

Rainfall patterns

✏️ Part 2: Short Answer Questions

Answer each question in full sentences.

5. In your own words, explain how convection currents cause tectonic plates to move. Use the words heat, rise, cool, and sink in your answer.

6. Explain how slab pull and ridge push work together to move tectonic plates. Which force do scientists think is stronger?

7. Australia sits in the middle of a tectonic plate and rarely experiences large earthquakes. However, countries like Japan and New Zealand experience them frequently. Using your knowledge of plate boundaries, explain why.

8. The Himalayas — the world's tallest mountain range — were formed by two continental plates colliding. Describe what happens when two continental plates push into each other. Why don't they subduct like oceanic plates?

🔬 Part 3: Diagram & Thinking Challenge

9. Label the diagram below by writing the correct term next to each arrow. Use the word bank provided.

Word Bank: Slab Pull | Ridge Push | Convection Current | Subducting Plate | Mid-Ocean Ridge

Draw a simple cross-section of two tectonic plates (one oceanic, one continental) showing a subduction zone on one side and a mid-ocean ridge on the other. Add arrows to show the direction of movement and label the three forces.

10. Thinking deeper: A volcano forms above a subduction zone. Explain the chain of events — starting from slab pull — that eventually leads to a volcanic eruption at the surface.

📋 Answer Key (Teacher Reference Only)

Part 1 — Multiple Choice

Q1: ✅ The weight of a dense, sinking oceanic plate pulling the rest of the plate along with it

Q2: ✅ Mid-ocean ridges where new crust is formed and plates are pushed apart

Q3: ✅ Heat from Earth's core causing hot material to rise and cool material to sink

Q4: ✅ Earthquakes, Volcanic eruptions, Mountain building (Rainfall patterns is NOT correct)

Part 2 — Short Answers (Guide)

Q5: Heat from Earth's core warms mantle rock, causing it to rise. As it reaches the upper mantle it cools, becomes denser, and sinks back down. This circular movement (convection current) drags tectonic plates along the surface.

Q6: At mid-ocean ridges, new magma pushes up and forces plates apart (ridge push). At subduction zones, the older, denser oceanic plate sinks and its weight drags the rest of the plate behind it (slab pull). Most scientists believe slab pull is the stronger of the two forces.

Q7: Australia sits in the centre of the Indo-Australian Plate, far from any plate boundaries. Japan and New Zealand sit on or near plate boundaries (subduction zones and transform faults) where plate movement causes stress and energy release as earthquakes.

Q8: When two continental plates collide, neither sinks because continental crust is less dense than oceanic crust. Instead, the crust crumples and folds upward, building mountain ranges like the Himalayas. Oceanic crust subducts because it is denser and heavier.

Part 3 — Diagram & Thinking

Q9 Diagram Labels: Mid-Ocean Ridge (centre, where plates separate), Ridge Push (arrows pointing outward from ridge), Subducting Plate (oceanic plate angling downward), Slab Pull (arrow pulling downward on the sinking plate), Convection Current (circular arrows in the mantle).

Q10: Slab pull drags the dense oceanic plate downward into the mantle (subduction). As the plate sinks deeper, the intense heat and pressure cause it to release water into the surrounding mantle rock. This lowers the melting point of the rock, creating magma. The magma is less dense than surrounding rock, so it rises through the crust. When pressure builds enough, it erupts at the surface as a volcano.