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Rock cycle

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Why this lesson, and why the 3D

Rock 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: Igneous, sedimentary, metamorphic. Arrows, not a one-way ladder. Temperature and pressure bias the path. By the end of the slot a pupil should be able to animate the trio and use T/P sliders to bias the path. Curriculum tags in the header (KS3; GCSE rocks; 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.

The Jurassic Coast and the Grand Canyon are one rock cycle at walking distance. Dorset’s Lias, Oolite and chalk are a sedimentary sequence you can stand on in an afternoon; Arizona’s walls are sandstone, shale and limestone stacked above Vishnu Schist. A UK party names beds. A US party names formations. Both sentences are about type, not about a birthday. GCSE and NGSS both ask students to move material among igneous, sedimentary and metamorphic without treating the poster as a one-way ladder. Age is independent of type: a Palaeozoic limestone is old and sedimentary; a Holocene basalt is young and igneous. Somerset Levels alluvium was rock somewhere up-catchment. Dust Bowl silt was a mineral in a parent. Yorkshire Dales limestone is a carbonate bed waiting for carbonation. A cliff, a soil and a quarry are the same budget in different rooms. Temperature and pressure light melt and metamorphism; weathering and lithification light the other arrows. UK coast, US canyon: same machine, different outcrop.

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 the trio out loud: igneous, sedimentary, metamorphic. Point at granite, beds, foliated rock. The arrows loop both ways. This is not a one-way ladder. Raise Temperature and Pressure. Watch the hot arrows toward metamorphic rock and melt. Drop both sliders. Cool weathering arrows toward sediment come back. Sedimentary is not always young. Age is independent of type. That is the misconception. Palaeozoic limestone is old and still sedimentary. Metamorphic needs heat and/or pressure on existing rock, without full melt in the school story. Then it can still melt. Sedimentary typically starts as weathered bits deposited then lithified. Grand Canyon walls. Jurassic Coast beds. Do not teach a staircase diagram. Do not invent a fourth rock. Finish in Check.

Open the lab full screen (F). Labels on (L). Speak the first step before you touch a slider: Three rocks. Arrows. Then the second: Raise T/P: toward metamorphic/melt. Then the third: Weathering toward sediment.

The sliders that earn their keep are Temperature; Pressure. Space plays; arrows nudge time; R resets. Parameters the URL can remember: temp, pressure. 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.

Orbit the trio. A granite plug with crystals sits on top. Horizontal sedimentary beds sit to the right. Foliated metamorphic beds sit to the left. Magma glows below. Play to watch the magma pulse. Raise Temperature and Pressure together. When their mean is high, hot arrows toward melt and metamorphism brighten and cool weathering arrows dim. Drop both sliders and the cool arrows return. Read T and P on the studio readout. Labels name the three rocks. Step the camera for a closer look at one type. The arrows loop both ways. Do not teach them as a ladder.

The in-site film is “What Are Rocks and How Do They Form? Crash Course Geography #17” (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.

“Sedimentary is ‘young’ always.” — no. Age is independent of type.

“The cycle is a one-way ladder: igneous, then sedimentary, then metamorphic.” — no. Any type can become any other if the conditions exist. Arrows loop.

“Metamorphic means the rock melted and froze again.” — no. School story: change in the solid. Full melt is igneous again.

Pitfalls to keep in your pocket: One-way diagram. Age equals type. Calling marble a sediment because it was once limestone. Full melt labelled metamorphic. 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

Igneous rock crystallises from melt. Intrusive bodies cool slowly and grow visible crystals; extrusive lava cools fast and is often finer. Weathering and erosion then break any rock into sediment. Deposition, burial, compaction and cementation lithify that sediment into sedimentary rock: beds you can count on a Dorset cliff or a canyon wall. If burial and tectonics raise temperature and pressure without a full melt, minerals recrystallise in the solid state. That is metamorphic rock, often foliated when directed stress is present. Raise heat further and the rock melts; magma is igneous waiting to happen again. Those are paths, not a ranking and not a staircase. Granite can weather to sand. Sandstone can become quartzite. Quartzite can melt. Limestone can become marble without ever being called young. In this lab the sliders bias the arrows: high temperature and pressure favour metamorphism and melt; cooler conditions keep the weathering arrow lit. School diagrams that draw a circle with three boxes are a cartoon of that network. The honest sentence is that any type can become any other if the conditions exist. Full melt is igneous. Change in the solid is metamorphic. Bits stuck together are sedimentary. That distinction is the plot.

The first place to land is Grand Canyon. The second is Jurassic Coast. 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 igneous texture you can name. An igneous texture you can name. This is the classroom sense of rock-cycle: a named landform, process, or object. 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 rock cycle. Field photograph or official scientific figure for teaching rock 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.

Igneous: Rock crystallised from melt. Intrusive cools slowly; extrusive cools at the surface. Sedimentary: Rock from deposited fragments or precipitates, then lithified. Metamorphic: Existing rock changed in the solid by heat and/or pressure, without full melt. Lithification: Compaction and cementation that turn sediment into sedimentary rock. Foliation: Layered mineral fabric from directed stress during metamorphism. Magma: Molten rock below the surface. Lava is the same material once it erupts. Weathering (to sediment): Breakdown that feeds the sedimentary path. Not the same as erosion.

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 you still have the cycle in sentences. Igneous crystallises from melt. Sedimentary is deposited bits lithified into beds. Metamorphic is existing rock changed in the solid by heat and pressure. Arrows run both ways: weathering toward sediment, burial and heat toward metamorphism and melt. The Jurassic Coast is a sedimentary sequence. Grand Canyon walls are that idea with metamorphic basement at the river. Sedimentary is not always young. Age is independent of type. Temperature and pressure bias the path; they do not invent a fourth rock. A one-way ladder is the diagram to refuse.

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. USGS rocks; BGS.

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 rocks; 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: Igneous, sedimentary, metamorphic. Arrows, not a one-way ladder. Temperature and pressure bias the path. Two: the misconception “Sedimentary is ‘young’ always.”. 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 temp, pressure. Send them home with the same link; there is no login.

In-site film

What Are Rocks and How Do They Form? Crash Course Geography #17. Crash Course Geography. Crash Course / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off. Autoplay off.