Tectonic Plates

Science · Volcanoes & Earthquakes · ages 9-11

Name ______________________ Date ____________

What material beneath tectonic plates lets them move over long periods?
- Cold, hard rock
- Hotter, softer mantle rock
- Ocean water
What are the huge moving pieces of Earth's rigid outer shell called?
- Tectonic plates
- One solid piece
- Melted rock only
Tectonic plates usually move a few centimetres per year.
Circle one: True False
This number line shows how far a plate moved during one year. How many centimetres did it move?
Answer: ______________
A mountain sits on a tectonic plate that carries it toward the west by 2 millimeters every year. How many millimeters will the mountain move in 10 years?
Answer: ______________
Which best describes the typical distance a tectonic plate moves in one year?
- A few kilometres
- It does not move at all
- A few centimetres
Why don't people feel the steady, very slow creep of a tectonic plate?
- It is too slow to notice
- Because plates do not really move
- Because plates only move at night
A tectonic plate moves 22 millimeters every year, about as fast as a fingernail grows. How many millimeters will it move in 100 years?
Answer: ______________
Two towns sit on plates moving apart. If that movement continues for many thousands of years, what will happen?
- The towns will be exactly the same distance apart
- The plates will suddenly stop moving
- The towns will be much farther apart
Mia says the ground under a mountain is fixed forever because rock is solid. What does she need to know?
- Rock is not really solid at all
- Solid plates can still move
- Mountains do not sit on plates

Answer key

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

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Hotter, softer mantle rock · The supporting mantle is mostly solid, but it can slowly flow and let the rigid plates move above it.
Tectonic plates · The rigid shell contains crust and the stiff uppermost mantle. Its separate pieces are called tectonic plates.
True · A few centimetres per year is a typical plate speed, though the rate differs from plate to plate.
4 · The arrow starts at 0 and ends at 4. That is a movement of 4 centimetres.
20 · Plates move very slowly, only a tiny bit each year. To find how far the mountain travels in 10 years, multiply the 2 millimeters it moves each year by 10.
A few centimetres · A few centimetres is the typical yearly scale. It is much less than kilometres, and it is not zero.
It is too slow to notice · The slow yearly creep is too small to feel as it happens. Sudden earthquake slip is different and can cause shaking.
2200 · Even though plates creep along slowly, the distance adds up over many years. Multiply the 22 millimeters per year by 100 years.
The towns will be much farther apart · The small increases in distance add up while the plates keep separating, so the towns end up farther apart.
Solid plates can still move · Solid describes the material, not whether its position can change. A mountain moves with its solid plate over the softer mantle beneath.