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GCSE AQA 3.1.3.2 · 15 minutes · no login

Mass movement

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Why this lesson, and why the 3D

Mass movement 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: Holderness till does not wait for a wave. After rain the cliff rotates on a curved shear and the toe shoves the beach. By the end of the slot a pupil should be able to name crown, shear surface and toe on a rotational slump, and say what rain does to the strength of till. Curriculum tags in the header (GCSE AQA 3.1.3.2; NGSS MS-ESS2-2) are filters, not a flag. The room is worldwide; SI first; International English. Ages on the card (GCSE, A-level, NGSS MS, HS Earth Sci) are a suggested band, not a gate.

Holderness loses metres of till each year. Waves undercut, but the cliff also fails on its own after rain: a rotational slump, crown dropping, toe shoving the beach. Palos Verdes, California, is the US pair — weak coastal sediment, water in the pores, a curved shear. AQA coasts and NGSS mass wasting both want this as a process you can turn, not a photograph of a scar. If a class only blames the North Sea, they will miss the wet week that actually dropped the block.

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

Name crown, scar, shear, toe on a still cliff. Do not play yet.\nAsk the third row what will make it fall. Wait.\nRaise rain. The block rotates. Crown drops. Toe shoves.\nThat is a slump, not a bite from the sea.\nHolderness till. Palos Verdes is the same machine.\nWaves pick the toe apart later — coasts lab, not this one.\nPore pressure reduces strength. Say that in school words.\nSpace, L, P. Then Check.

Open the lab full screen (F). Labels on (L). Speak the first step before you touch a slider: Name crown, scar, shear, toe on a still cliff. Then the second: Raise pore pressure. The block rotates. Then the third: Rain weakens till. Waves only remove the toe.

The sliders that earn their keep are Pore pressure. Space plays; arrows nudge time; R resets. Parameters the URL can remember: rain. 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.

Leave rain low. Name crown, scar, shear, toe. Raise pore pressure. Watch the block rotate — do not skip to the beach. Keyboard: Space play, arrows, L labels, R reset, P projector. The rain slider is the plot. Ask what the third row thinks makes the cliff fall before you move it.

The in-site film is “How Does the Earth Create Different Landforms? Crash Course Geography #19” (Crash Course Geography, about 13 min, Crash Course / 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.

“The sea ate the whole cliff in one bite.” — no. Waves remove debris. Failure often starts as a wet slump on a curved shear.

“Landslides are just fast rockfalls.” — no. A slump rotates. A flow mixes. A fall is free. Name the machine.

“Dry cliffs are the dangerous ones.” — no. Pore water is the usual trigger in till. Rain first, then the drop.

Pitfalls to keep in your pocket: Blaming only waves. Calling every failure a rockfall. Treating dry cliffs as the hazard. 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 water in the pores. Till is glacial sediment: strong when dry-ish, weak when saturated. Effective strength falls as pore pressure rises. Failure finds a curved surface. The head drops and tilts back; the toe shoves out. That is a slump, not a rockfall and not a flow. What moves: the block, rotating about a hinge. What does not: the idea of a shear surface. What is conserved: mass of the failed slice, until waves pick the toe apart. The lie the model tells: one clean spoon-shaped cut, sped up from days to a slider. Real Holderness is many slices, many wet weeks. Vertical exaggeration so the back row can see the rotation. Waves in the coasts lab remove debris. This lab is the failure itself.

The first place to land is Holderness till cliffs. The second is Hong Kong slopes. 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: A landslide scar and a hummocky toe. A landslide scar and a hummocky toe. Downslope movement of rock or soil under gravity. Source: Wikimedia Commons / NASA / USGS / NOAA, public domain or CC. Credit: Wikimedia Commons / NASA / USGS / NOAA, public domain or CC.

Mechanism photograph: Field or official figure for teaching Mass movement. A second photograph for the projector script — not the lab cover. Credit: Wikimedia Commons / NASA / USGS.

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.

Rotational slump: A slice of slope that rotates on a curved shear. Crown drops; toe shoves. Shear surface: The failure plane. Curved in a slump. Not a vertical cliff face. Crown: The upslope crack and head of the failed block. Toe: The downslope bulge. On a coast, waves pick it apart. Pore pressure: Water pressure in the gaps. Raised, it reduces effective strength. Till: Unsorted glacial sediment. Holderness cliffs are till. Weak when wet. Mass movement: Downslope movement of rock or soil under gravity. Water is a trigger, not the transport. Exam language also accepts “Mass wasting”.

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: a rotational slump rides a curved shear. Rain raises pore pressure and the till fails. Crown drops, toe shoves. Holderness till; Palos Verdes coastal slides. Waves remove the toe later. Rockfall is a different machine: free fall of jointed rock. This lab is the spoon scoop. 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 mass movement; USGS landslides.

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 (GCSE AQA 3.1.3.2; NGSS MS-ESS2-2) are filters, not a flag. A class in Nairobi, London, or Shanghai can use the same 3D. Ages (GCSE, A-level, NGSS MS, 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: Holderness till does not wait for a wave. After rain the cliff rotates on a curved shear and the toe shoves the beach. Two: the misconception “The sea ate the whole cliff in one bite.”. 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 rain. Send them home with the same link; there is no login.

In-site film

How Does the Earth Create Different Landforms? Crash Course Geography #19. Crash Course Geography. Crash Course / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off. Autoplay off.