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GCSE AQA 3.1.1.3 · 15 minutes · no login

Volcanoes

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Why this lesson, and why the 3D

Volcanoes 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: Viscosity is the plot. Shield, strato, rift — three shapes from one slider. By the end of the slot a pupil should be able to contrast shield, stratovolcano, and rift; use a viscosity slider. Curriculum tags in the header (GCSE AQA 3.1.1.3; NGSS MS-ESS2-2) 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.

Viscosity is the plot, not ‘bigger boom’ as a personality trait. Hawaii’s Mauna Loa and Kīlauea are shields: low-viscosity basalt, long flows, gentle slopes on a hotspot under an oceanic plate. Cascadia’s arc — St Helens, Rainier, Hood — is the sticky end-member: water from the slab, andesite and dacite, layers of lava and ash, steep cones. Iceland sits on the Mid-Atlantic Ridge plus a plume: usually basalt fissures you can walk at places like Thingvellir, and occasional explosive events when ice and evolved magma meet, as in Eyjafjallajökull 2010. GCSE AQA 3.1.1.3 and NGSS want that contrast without a league table of famous eruptions. San Andreas does not make this chain; it slides. Katrina and Sandy are a different hazard. One slider, three shapes: shield, strato, rift. UK students meet these as named case studies, not as a local cone. The chemistry and the gas decide the slope. The poster that says all volcanoes explode has already failed the lab.

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

Slider low. This is a shield: low viscosity basalt, a crater, a wide slope. Hawaii. Drop viscosity further. A fissure opens. Iceland is this, not a cartoon cube. Raise viscosity. The same conduit steepens into a stratovolcano. Cascades, St Helens. Keep raising. An ash column appears only when magma is sticky. Slice or step to the conduit. Magma is a path, not a random cone. Ask why sticky magma explodes and runny magma pours. Viscosity is the plot. All volcanoes do not explode. Basalt often pours. Explosions need gas and stickiness. That is the misconception. Do not teach supervolcano headlines as the whole course. Do not put San Andreas under a cone. Finish in Check.

Open the lab full screen (F). Labels on (L). Speak the first step before you touch a slider: Low viscosity: shield. High: strato. Rift: fissure. Then the second: Slide viscosity. Then the third: Hawaii vs St Helens vs Iceland fissure.

The sliders that earn their keep are Viscosity. X slices the volume so a hidden plane can be seen. Space plays; arrows nudge time; R resets. Parameters the URL can remember: visc. 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 Viscosity low. This is a shield: a crater, a wide slope, low-viscosity basalt. Drop it further and a fissure opens — Iceland’s habit, not a cube. Raise the slider. The same conduit steepens into a stratovolcano. Keep going and an ash column appears only because the melt is sticky. Slice or step to the conduit: magma is a path, not a random cone. Name Hawaii, Iceland, Cascades after the shapes, not before. Orbit. Then sit down in Check.

The in-site film is “What Are Volcanoes? Crash Course Geography #20” (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.

“All volcanoes explode.” — no. Basalt often pours. Explosions need gas and stickiness.

“Bigger volcano means bigger boom.” — no. Viscosity and gas set the style. Shields can be huge and quiet-ish.

“Every volcano sits on the Ring of Fire.” — no. Hawaii is a hotspot. Iceland is a ridge plus a plume.

Pitfalls to keep in your pocket: Supervolcano headlines as the whole course. All volcanoes explode. Ring of Fire as the only address. Shields called worn-down stratovolcanoes. 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

Magma is silicate liquid plus crystals plus dissolved gas. Viscosity is resistance to flow. Low silica, hot, crystal-poor basalt is runny: gas escapes, lava travels far, the edifice spreads into a shield. High silica, cooler, stickier melts hold gas. Pressure builds, fragmentation makes ash, and the cone steepens as lava and pyroclasts stack: a stratovolcano, a composite cone. A divergent boundary can skip the cone and erupt along a fissure — Iceland’s ridge habit, not a cartoon cube. Hotspot versus arc versus ridge is the setting; viscosity is still the plot inside the conduit. Water from a subducting slab lowers melting point in the mantle wedge and tends to give the Cascades their sticky, explosive character. A plume under ocean crust, Hawaii, tends to give basalt. Ice on a central volcano can add ash even when the ridge itself is basaltic. Supervolcano headlines are not a course. Yellowstone is a continental hotspot, a different lab. Here the crater and channel stay while the slope steepens as you raise the slider. Ask why sticky explodes and runny pours. That question is the mechanism.

The first place to land is Hawaii shields. The second is Iceland rift. 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 steep stratovolcano cone. A steep stratovolcano cone. This is the classroom sense of volcanoes: 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 or official figure for teaching Volcanoes. 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.

Viscosity: Resistance to flow. High viscosity plus gas makes explosive eruptions more likely. Shield volcano: Broad, gentle edifice from low-viscosity basalt. Mauna Loa type. Stratovolcano: Steep cone of lava and ash from stickier magma. Cascades type. Exam language also accepts “Composite cone”. Fissure eruption: Magma erupting along a crack, often basalt at a rift. Iceland habit. Basalt: Low-silica, typically runny lava. Builds shields and many rift flows. Conduit: The path magma takes through the edifice. Not a random cone. Pyroclastic: Fragmented material from explosive eruption: ash, pumice, blocks.

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 viscosity is still the plot. Shield volcanoes: low-viscosity basalt, long flows, gentle slopes — Hawaii. Stratovolcanoes: stickier, gassier magma, layers of lava and ash, steep cones — Cascadia’s arc. A rift eruption can be a basalt fissure at a divergent boundary — Iceland. Not all volcanoes explode. Basalt often pours. Explosions need gas and stickiness. San Andreas is a slide, not this chain. One slider, three shapes. Do not teach supervolcano headlines as the whole course. Viscosity still decides the shape.

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 volcanoes; IMO.

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 3.1.1.3; NGSS MS-ESS2-2) 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: Viscosity is the plot. Shield, strato, rift — three shapes from one slider. Two: the misconception “All volcanoes explode.”. 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 visc. Send them home with the same link; there is no login.

In-site film

What Are Volcanoes? Crash Course Geography #20. Crash Course Geography. Crash Course / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off. Autoplay off.