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A-level plate tectonics · 15 minutes · no login

Wilson cycle

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Why this lesson, and why the 3D

Wilson cycle is a fifteen-minute projector lesson, not a homework packet and not a film with a quiz bolted on. Put this hook on the board before you dim the lights: The Atlantic is opening. One day it will close. The Caledonides and the Appalachians are an older ocean that already did. By the end of the slot a pupil should be able to scrub rift → ocean → subduction → collision and treat the Caledonides and Appalachians as one old ocean’s scar. Curriculum tags in the header (A-level plate tectonics; NGSS HS-ESS2-1) are filters, not a flag. The room is worldwide; SI first; International English. Ages on the card (A-level, HS Earth Sci) are a suggested band, not a gate.

Scotland’s Caledonian mountains and the US Appalachians are not two mysteries. They are one old ocean that opened and shut, then weathered. Today’s Atlantic is the open chapter of the same play. A-level tectonics and HS-ESS2 want the cycle as a process you can scrub, not a named era to memorise. If Pangaea is taught as a one-off, the next collision is a surprise.

The 3D is a named, inspectable object. Click the part, not a caption. If the model will not spin, the Why panel still carries the mechanism, the two photographs, and the film. Do not apologise for the model. Drive it. A silent spin teaches a screensaver. A named mesh that changes under a slider teaches the process.

Fifteen minutes on the projector

Start at rift. A continent splitting.\nScrub to open ocean. Iceland lives here.\nScrub toward a trench. The ocean starts to close.\nCollision. Caledonides. Appalachians. One scar, two names.\nAsk whether Pangaea was the only gathering. It was not.\nThe Atlantic will not stay this width forever on geologic time.\nArrows on the stage. L, P. Then Check.

Open the lab full screen (F). Labels on (L). Speak the first step before you touch a slider: A continent rifts. Then the second: An ocean opens, like today’s Atlantic. Then the third: It closes. Collision. Caledonides / Appalachians.

The sliders that earn their keep are Stage. Space plays; arrows nudge time; R resets. Parameters the URL can remember: stage. If you only have eight minutes, skip the last step and finish in Check. Projector layout (P) is for the back row: one idea, large type, the model still live.

Scrub Stage from rift to collision. Pause on ocean. Point at Iceland as that chapter. Pause on collision. Caledonides, Appalachians. Keyboard: arrows on the stage, L, R, P. Do not skip a stage. Name the job at each stop before the place.

The in-site film is “What is Plate Tectonics: Crash Course Geology #10” (Crash Course Geology, about 10 min, Crash Course Geology / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off.). Autoplay is off. Play one minute if you need a second voice; do not let the film eat the slot. The 3D still has to move under your hand.

What the third row will get wrong

You will hear the misconception before you have finished the first sentence. Write the false claim on the board and leave it there until the model has contradicted it. Do not skip this. A fluent pupil can recite the hook and still believe the false sentence.

“Pangaea was the only time continents gathered, and the Atlantic will stay.” — no. Oceans open and close. The Caledonides already did this play.

“Mountains are just wrinkled crust with no ocean in their past.” — no. Collision belts often close an ocean first.

“Iceland is a collision orogeny.” — no. Iceland is a ridge on an opening ocean.

Pitfalls to keep in your pocket: Pangaea as a one-off. Iceland as a collision. Mountains with no ocean in their past. Do not let a pupil leave thinking the 3D is a photograph. It is a teaching model. Where vertical exaggeration exists, T collapses it and the caption says so. A labelled lie of scale is honest. An unlabelled one is a cartoon.

Two places, not a slogan

Input is time, in stages. A continent rifts — East African flavour, but this is a teaching strip. Ocean crust is born at a ridge; the basin widens. One margin can become a trench; the ocean starts to close. Collision stacks crust; a mountain belt. Erosion and isostasy then wear it. What moves: the stage. What does not: the menu of jobs from the plate-boundaries lab. What is conserved: lithosphere created and later destroyed. The lie: six clean stages, no microplates, a straight strip not a sphere. Real Wilson cycles overlap. Real Caledonian–Appalachian geometry is a puzzle of terranes. This lab is the loop, not the map. Iceland is today’s ridge, not a collision. Himalaya is collision now. The UK rides a quiet margin of a still-opening Atlantic.

The first place to land is Atlantic still opening. The second is A different job on a different edge. Same process, different rock or climate. If a pupil can only name one place, they have a postcard, not a mechanism. Atlas entries for those names are a click from the case list; send them back to the lab with one sentence they can say in Check.

Do not flatten the comparison into “this country versus that country.” Name the landform. Holderness is till, not chalk. Hawaii is a hotspot, not an island arc. Yosemite is a glacial trough, not a river canyon. The 3D is allowed to be schematic; the place names are not allowed to be sloppy.

Figures and the film

Field photograph: An ophiolite: seafloor parked on land. An ophiolite: seafloor parked on land. The opening and closing of ocean basins, named for Tuzo Wilson. Source: Wikimedia Commons / NASA / USGS / NOAA, public domain or CC. Credit: Wikimedia Commons / NASA / USGS / NOAA, public domain or CC.

Mechanism photograph: Field photograph or official scientific figure for teaching wilson cycle. Field photograph or official scientific figure for teaching wilson cycle. A second photograph for the projector script — not the lab cover. Source: Wikimedia Commons / NASA / USGS / NOAA, public domain or CC. Credit: Wikimedia Commons / NASA / USGS / NOAA, public domain or CC.

Two photographs, two jobs. The field picture is the place. The mechanism picture is the process. Do not run the lesson on a single Apollo Earth disc. A carbon-cycle class is a forest and a seam, not a blue marble. An ENSO class is a Pacific temperature map, not Africa from Apollo 17.

Words they must be able to say

Say these out loud once while you click the matching mesh. If a word has no mesh, it still has a photograph in Terms.

Wilson cycle: The opening and closing of ocean basins, named for Tuzo Wilson. Rift: A continent splitting. The birth of an ocean. Passive margin: A quiet continent–ocean edge after rifting, like much of the modern Atlantic. Orogeny: A mountain-building episode, often from collision. Caledonides: Palaeozoic collision belt through Scotland and Norway. Pair of the Appalachians. Appalachians: The North American scar of that same old ocean’s close. Terrane: A crustal piece with its own history, later stitched on. This lab omits them on purpose.

Exam-language toggle (the Teacher tab) swaps UK/US pairs where they exist — levée/levee, arête/arete — so a mixed room is not punished for spelling.

Close the slot

Without the canvas: oceans open and close. Rift, ocean, trench, collision, wear. Caledonides and Appalachians are a closed ocean’s scar. The Atlantic is still opening. Iceland is a ridge. Himalaya is collision. Pangaea was a gathering, not the only one. That is enough for Check.

Finish in Check — ten questions, not a mood. The bank mixes definition, process, the misconception you just killed, a named place, and a read-the-model item (click the part; T). If a pupil can only recite the hook, they have not used the geometry. Wrong answers still show the one-line explain. Do not skip the explain.

Sources on the Teacher tab are the trail, not a bibliography to copy. BGS Caledonian; USGS Appalachians.

Link back to the live lab and keep the same slug. Do not invent a parallel worksheet that contradicts T, SI, or the named parts.

This note is worldwide. Curriculum tags (A-level plate tectonics; NGSS HS-ESS2-1) are filters, not a flag. A class in Nairobi, London, or Shanghai can use the same 3D. Ages (A-level, HS Earth Sci) are a suggested band. If a sentence only works in one exam board, rewrite it before you project it.

Write these three lines on the board before you dim the lights. One: The Atlantic is opening. One day it will close. The Caledonides and the Appalachians are an older ocean that already did. Two: the misconception “Pangaea was the only time continents gathered, and the Atlantic will stay.”. Three: the named parts they must click. Then drive the model. Check is ten questions covering definition, process, the misconception, a place, and a read-the-model item. Do not skip the explain on a wrong answer.

Board, units, and what not to say

SI first. Metres, kilometres, degrees Celsius, metres per second. A conversion in brackets is courtesy, not a second system. Do not let a pupil leave thinking the 3D is a photograph. It is a teaching model. Where vertical exaggeration exists, T collapses it and the caption says so.

Do not say “teaching mesh”, “sprinkle”, or “thin free surface not a fat pipe” out loud. Say the landform. Seasons are ~23.44° of axial tilt, not Earth–Sun distance. The outer core is liquid; S-waves do not pass. Yosemite is a glacial U-trough. San Andreas is a transform. Hawaiʻi and Yellowstone are hotspots. Florida is not a glacial trough.

If the room is noisy, projector layout (P) is the back-row setting: one idea, large type, the model still live. Full screen (F). Labels (L). Space plays. Arrows nudge time. R resets. The URL can remember stage. Send them home with the same link; there is no login.

In-site film

What is Plate Tectonics: Crash Course Geology #10. Crash Course Geology. Crash Course Geology / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off. Autoplay off.