Where plates meet: boundaries that shake and build

Science · Volcanoes & Earthquakes · ages 9-11

Name ______________________ Date ____________

What is it called when two plates slide past each other sideways?
- Convergent boundary
- Divergent boundary
- Transform boundary
What is it called when two plates push together?
- Divergent boundary
- Convergent boundary
- Transform boundary
Earthquakes happen where plates grind or collide at their edges.
Circle one: True False
Two plates are grinding past each other, but the rock is stuck instead of sliding smoothly. What is building up?
- A brand new ocean
- A steady, gentle flow of rock
- Stress in the stuck rock
At a boundary where one plate sinks under another, how can the sinking plate help magma form?
- It releases water that helps rock above it melt
- It turns instantly into a mountain
- It floats back up unchanged
Two continental plates collide. Their crust crumples and thickens. What can grow over time?
- A flat desert
- Tall mountains
- A deep ocean trench
A boundary has no volcanoes and no new mountains, but sudden jolts shake the ground as the plates grind sideways. Which boundary is this most likely?
- Transform boundary
- Convergent boundary
- Divergent boundary
Theo says volcanoes only form where plates pull apart, never where they push together. Is he right?
- Yes, that is exactly right
- No, volcanoes never form at plate boundaries
- No, they also form above sinking plates

Answer key

For grown-ups. Fold this page away before handing over the rest.

Transform boundary · Plates sliding sideways past each other meet at a transform boundary.
Convergent boundary · When plates push together, that meeting edge is called a convergent boundary.
True · Rock at plate edges can stick, build stress, and suddenly slip. That slip releases earthquake waves.
Stress in the stuck rock · The plates keep moving while some rock stays stuck. Stress builds in that rock until it can slip.
It releases water that helps rock above it melt · Water leaves the sinking plate and helps some hot mantle rock above it melt. This can supply magma for volcanoes.
Tall mountains · The collision squeezes and thickens the continental crust, lifting parts of it into tall mountains.
Transform boundary · Sliding sideways without much up-and-down motion is the mark of a transform boundary.
No, they also form above sinking plates · Volcanoes can form where plates pull apart and where a sinking plate releases water that helps mantle rock above it melt.