Plate Boundaries — Drills · Grade 9 Science
Chapter: Earth’s Interior & Plate TectonicsWhat these drills covers
By the end of Plate Boundaries you should be able to:
- I can identify divergent, convergent, and transform plate boundaries from a description or diagram.
- I can distinguish the three types of convergent boundaries and predict what landform each one creates.
- I can explain why earthquakes and volcanoes cluster along plate boundaries.
8 questions, multiple choice, numeric and written answer, each with a worked explanation.
Vocabulary used: divergent boundary, convergent boundary, transform boundary, subduction.
Problem 1
- move apart
- collide
- slide past each other
- stop moving
Answer and explanation
move apart
Divergent boundaries pull apart, allowing new crust to form.
Problem 2
- subduction zones
- mid-ocean ridges
- transform faults
- continental interiors
Answer and explanation
mid-ocean ridges
Magma rises at the ridge and solidifies, adding new crust.
Problem 3
- rides over the top
- subducts beneath
- stops
- turns into continental crust
Answer and explanation
subducts beneath
Oceanic crust is denser, so it descends beneath the less dense continental crust.
Problem 4
- move apart
- collide head on
- slide past each other horizontally
- are created
Answer and explanation
slide past each other horizontally
Transform motion is lateral, which is why these boundaries produce earthquakes but little volcanism.
Problem 5
Answer and explanation
1000 cm
5 × 200 = 1,000 cm, or 10 m.
Problem 6
Answer and explanation
50 years
200 cm / 4 cm per year = 50 years.
Problem 7
Answer and explanation
Heat from Earth's interior drives slow convection in the mantle, and that flow, together with the pull of dense subducting slabs, moves the plates above. The evidence is indirect because the flow is far too deep and too slow to observe: it is inferred from measured plate velocities, heat flow, the pattern of earthquakes with depth, and seismic images of the mantle.
Response criteria
- State a scientifically accurate conclusion.
- Show the data, mechanism, or calculation that supports it.
- Include units, conditions, or limits where relevant.
Problem 8
Answer and explanation
Divergent boundaries release magma relatively gently and produce shallow earthquakes, so hazards are moderate and often undersea. Convergent boundaries force one plate down, generating the deepest and largest earthquakes and explosive volcanoes, so hazards are greatest there. Transform boundaries grind laterally, producing frequent shallow earthquakes but little volcanism. The motion determines what builds up and how it is released.
Response criteria
- State a scientifically accurate conclusion.
- Show the data, mechanism, or calculation that supports it.
- Include units, conditions, or limits where relevant.