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KS3 · 15 minutes · no login

Weathering

All teacher notes · Open the lab · 1944 words · ·

Why this lesson, and why the 3D

Weathering 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: Mechanical, chemical, biological — three blocks, side by side, not a ranking of virtue. By the end of the slot a pupil should be able to compare frost, carbonation, and roots on three rocks. Curriculum tags in the header (KS3; GCSE; NGSS MS-ESS2-1) are filters, not a flag. The room is worldwide; SI first; International English. Ages on the card (KS3, GCSE, NGSS MS) are a suggested band, not a gate.

Weathering is rock breakdown in place. It is not the Met Office forecast and it is not erosion. UK limestone country makes the chemical case: Yorkshire Dales pavements, grykes and swallow holes are carbonation along joints, rainwater plus carbon dioxide as a weak acid. The US pair in this lab is the Grand Canyon stack: joints, unloading, and freeze on the rim open the walls; the river then exports what falls. Jurassic Coast cliffs add salt, spray and lithology changes along the shore. Somerset Levels sit on already-weathered fines. Dust Bowl silt was a weathered particle that wind later moved — weathering first, transport second. GCSE and NGSS both want three agents named without a league table: mechanical, chemical, biological. Climate chooses the mix. Frost-heavy uplands favour ice in cracks. Warm wet carbonate country favours carbonation. Roots and lichens work wherever they can sit. Three blocks, side by side, not a ranking of virtue.

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

Point at each of the three blocks: mechanical, chemical, biological. Play. Frost wedges: water freezes, expands. Mechanical. Carbonation pits carbonate rock with weak carbonic acid. Chemical. Karst cousin. Dales. Roots, lichens, burrowers. Biological. Climate chooses the mix. Not a ranking of virtue. Weathering is not weather. Weathering is rock breakdown. Weather is the atmosphere’s mood. That is the misconception. Do not mix erosion with weathering. Weathering breaks. Erosion moves. Grand Canyon walls weather; the river exports. Finish in Check.

Open the lab full screen (F). Labels on (L). Speak the first step before you touch a slider: Three blocks. Then the second: Frost wedges. Carbonation pits. Roots. Then the third: Climate chooses the mix.

Time, labels, and T (true scale) are the whole desk. Play walks the process; T removes the vertical lie where one was drawn. Space plays; arrows nudge time; R resets. Parameters the URL can remember: t, labels, true scale. 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.

Play. Three blocks advance together. Left: frost wedges a granite cube as ice thickens in the crack. Middle: carbonation pits a carbonate face — the karst cousin. Right: a root thickens in a joint. Orbit so each agent is named. They are not a ranking. Pause and ask which block would dominate in the Dales (chemical on limestone) and which on a freezing canyon rim (mechanical). Do not skip the labels Physical, Chemical, Biological. The readout says three mechanisms side by side. That is the lesson. Then sit down.

The in-site film is “What is Weathering? Crash Course Geography #21” (Crash Course Geography, about 11 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.

“Weathering is weather.” — no. Weathering is rock breakdown. Weather is the atmosphere’s mood.

“Weathering and erosion are the same word.” — no. Weathering breaks in place. Erosion moves the bits.

“Chemical weathering is ‘stronger’ than mechanical.” — no. Climate chooses the mix. Not a ranking of virtue.

Pitfalls to keep in your pocket: Erosion vs weathering mix-up. Weathering as the forecast. Ranking the three agents as good, better, best. Carbonation taught on granite as the default. 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

Mechanical weathering breaks rock without changing the minerals. Frost shattering is the school example: water in a joint freezes, expands, and wedges the block. Unloading and thermal stress do similar work on canyon rims and granite sheets. Chemical weathering changes the minerals. Carbonation is the carbonate special: carbonic acid from rain and soil air attacks calcite, widening joints into grykes and feeding caves. Hydrolysis and oxidation work on silicates and iron; they matter, but this lab’s chemical block is the karst cousin you can see. Biological weathering is living agents: roots pry joints, lichens etch, burrowers mix. It is not a separate physics; it is mechanical and chemical work done by organisms. The three overlap. A root in a Dales gryke is biological and mechanical on a chemically opened crack. Weathering produces sediment and soil parent material; erosion carries it. Mix those verbs and the Grand Canyon becomes a riddle: the walls weather and fail, the river removes. Climate sets rates, not moral rank. Cold wet, warm wet, and rooted surfaces write different mixes of the same three blocks on any one hillside.

The first place to land is Carbonation. The second is Hong Kong granite saprolite. 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: Spheroidal weathering of granite. Rock to sediment in place. Credit: Wikimedia Commons, CC BY.

Mechanism photograph: Field or official figure for teaching Weathering. 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.

Mechanical weathering: Break without composition change. Frost, unloading, thermal stress. Exam language also accepts “Physical weathering”. Chemical weathering: Change the minerals. Carbonation, hydrolysis, oxidation. Biological weathering: Living agents: roots, lichens, burrowers. Mechanical and chemical work by organisms. Frost shattering: Water in a joint freezes, expands, and wedges the rock. Exam language also accepts “Freeze–thaw”. Carbonation: Weak carbonic acid attacking carbonate rock. Karst’s chemistry. Weathering: Rock breakdown in place. Not the atmosphere’s mood. Erosion: Movement of weathered material by water, wind, ice or gravity.

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 the three agents still stand. Mechanical: frost shattering, water freezes and expands in a crack. Chemical: carbonation, weak carbonic acid on carbonate rock — Yorkshire Dales karst. Biological: roots, lichens, burrowers. Weathering is rock breakdown, not the weather forecast. Weathering breaks in place; erosion moves the bits. Climate chooses the mix; there is no league table. Grand Canyon joints and Dales grykes are the locators. Name break versus transport before you leave the page. Play is optional; the three agents are not.

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 weathering; USGS.

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 (KS3; GCSE; NGSS MS-ESS2-1) are filters, not a flag. A class in Nairobi, London, or Shanghai can use the same 3D. Ages (KS3, GCSE, NGSS MS) 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: Mechanical, chemical, biological — three blocks, side by side, not a ranking of virtue. Two: the misconception “Weathering is weather.”. 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 t, labels, true scale. Send them home with the same link; there is no login.

In-site film

What is Weathering? Crash Course Geography #21. Crash Course Geography. Crash Course / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off. Autoplay off.