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A-level · 15 minutes · no login
River regime
All teacher notes · Open the lab · 2021 words · ·
Why this lesson, and why the 3D
River regime 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: A UK upland nival/pluvial mix vs the Mississippi: the same year, different graphs. By the end of the slot a pupil should be able to compare two annual regimes and say what rain, snowmelt and dams do to the year’s personality. Curriculum tags in the header (A-level; GCSE) are filters, not a flag. The room is worldwide; SI first; International English. Ages on the card (A-level, GCSE, APES) are a suggested band, not a gate.
A Lake District beck and the Mississippi are the same year on different graphs. UK upland catchments often mix winter rain with a spring snowmelt bump; the west coast is frequently pluvial. The Mississippi is a continental drain with snowmelt, rain and a dam-managed year — do not invent cubic metres. Colorado’s snowpack is a nival store that becomes spring discharge; dams then flatten what the mountain wrote. Regime is why a reservoir rule-curve and a UK abstraction licence care about the month, not the Thursday storm. Hydrograph is hours. This lab is the year. All rivers do not peak in summer. Alps, Rockies and a Cumbrian winter disagree with a tropical wet season, and that is the point of two traces on one axis.
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
Play the year. Two traces: a UK upland and the Mississippi. Name the bump. UK upland: rain plus a snowmelt bump, nival and pluvial mixed. A nival regime is snowmelt. A pluvial regime follows rainfall seasonality. The Mississippi is a continental drain with snowmelt and rain, managed by dams. Do not invent numbers. Regime is the year’s personality, not one storm. Hydrograph is hours; this is the year. All rivers do not peak in summer. That is the misconception. It depends on rain, snow, dams, ice. Colorado’s pack is a nival store; dams then flatten. One graph is not all climates. Say so. Ask which trace would change if you turned snow off in the story. Finish in Check.
Open the lab full screen (F). Labels on (L). Speak the first step before you touch a slider: Play the year. Two traces: a UK upland and the Mississippi. Name the bump. Then the second: UK upland: rain plus a snowmelt bump, nival and pluvial mixed. Mississippi: a broader continental year, managed by dams. Then the third: Regime is the year’s personality, not one storm. Hydrograph is hours; this is the year.
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 the year. Two traces: nival UK highland and Mississippi pluvial. Pause on the UK spring bump and name it snowmelt. Scrub the Year slider month by month and ask which trace would change if you turned snow off in the story. Hide labels (L) and make the class assign nival versus pluvial. Watch the marker walk J to D; a snow sphere lights on the UK ribbon in spring. Keyboard: space play, arrows scrub the year, L labels, R reset. Speed 1× / 2× / 4× is in the bar. Finish in Check.
The in-site film is “How Rivers Shape the Landscape: Crash Course Geography #22” (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.
“All rivers peak in summer.” — no. Depends on rain, snow, dams, ice.
“A storm hydrograph and a regime graph are the same plot.” — no. Hours versus the year. Do not paste a rising limb onto a monthly axis.
“One graph will do for all climates.” — no. UK upland mix, Mississippi continental year, Colorado snowpack: different machines, same idea.
Pitfalls to keep in your pocket: One graph for all climates. Pasting a storm hydrograph onto a monthly axis. Inventing peak-flow numbers the traces do not give. 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
Regime is the typical annual variation of discharge — the year’s personality, not one storm. A nival regime is snowmelt-dominated: a spring peak as the pack goes. A pluvial regime follows rainfall seasonality: UK western winters often sit here. Many UK upland rivers are a mix: rain in the wings, a snowmelt bump in spring. The Mississippi trace in this lab is a broader continental year, rain-fed with a snowmelt contribution and flattened in the real world by dams. Play the year and watch two ribbons: UK highland nival-green, Mississippi pluvial-blue. A marker walks the month. A snow sphere lights on the UK trace in spring. All rivers do not peak in summer. It depends on rain, snow, ice and management. A glacier-fed river can peak later still. Colorado’s pack is the same nival idea at drier numbers; dams then rewrite the month. Do not paste a storm hydrograph onto a monthly axis. Hours and months are different machines. One graph is not all climates. The traces are school shapes, not NRFA or USGS station numbers — do not invent a peak flow and write it in an exam.
The first place to land is UK upland. The second is Mississippi. 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 braided channel at high stage. A braided channel at high stage. This is the classroom sense of river-hydrology: 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 River hydrology. 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.
Regime: Typical annual variation of discharge. The year’s personality, not one storm. Nival: Snowmelt-dominated regime. Spring peak as the pack goes. Pluvial: Rainfall-seasonality regime. UK west is often pluvial. Snowmelt: Stored winter snow becoming spring discharge. A nival bump. Discharge: Volume per time. Regime plots it by month, not by hour. Exam language also accepts “Q”. Baseflow: The slow groundwater contribution that sits under the year’s wiggles. Dam regulation: Storage that flattens or shifts the natural year. Mississippi and Colorado both live with it.
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 3D view: two annual traces. UK upland: rain plus a snowmelt bump. Mississippi: a broader continental year, managed by dams in the real river. Nival is snowmelt. Pluvial follows rain. Regime is the year; a storm hydrograph is hours. All rivers do not peak in summer. Colorado’s snowpack is a nival store that dams can flatten. The ribbons are school shapes, not station numbers. Do not invent cubic metres. One graph is not all climates. Say so plainly.
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. NRFA; 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 (A-level; GCSE) are filters, not a flag. A class in Nairobi, London, or Shanghai can use the same 3D. Ages (A-level, GCSE, APES) 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: A UK upland nival/pluvial mix vs the Mississippi: the same year, different graphs. Two: the misconception “All rivers peak in summer.”. 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.
A Lake District beck and the Mississippi are the same year on different graphs. UK upland catchments often mix winter rain with a spring snowmelt bump; the west coast is frequently pluvial. The Mississippi is a continental drain with snowmelt, rain and a dam-managed year — do not invent cubic metres. Colorado’s snowpack is a nival store that becomes spring discharge; dams then flatten what the mountain wrote. Regime is why a reservoir rule-curve and a UK abstraction licence care about the month, not the Thursday storm. Hydrograph is hours. This lab is the year. All rivers do not peak in summer. Alps, Rockies and a Cumbrian winter disagree with a tropical wet season, and that is the point of two traces on one axis.
In-site film
How Rivers Shape the Landscape: Crash Course Geography #22. Crash Course Geography. Crash Course / Complexly on YouTube. Standard YouTube licence. Educational embed, autoplay off. Autoplay off.