Find a lab, a word, a place.

Press / to focus. SI names and ordinary English both work. Not a fifth product card.

Labs · 3

Why seasons happenIn December, London is dark by late afternoon while Sydney is in high summer. The Earth is not closer to the Sun in July.
Storm hydrographRain is the input. The river’s reply has a rising limb, a peak, a lag, a falling limb.
CoastsConstructive waves build. Destructive waves take. Longshore drift is the conveyor. Cave–arch–stack–stump is the headland’s life.

Terms · 6

Cirque
A cirque is a steep-walled armchair hollow at the head of a valley glacier, cut by freeze–thaw on the back wall and rotational ice at the floor. A tarn often ponds there after the ice leaves. Helvellyn’s Red Tarn is the UK classroom pair; the Alps and the Rockies repeat the same bowl. It is not a volcanic crater and not a river meander. If three cirques eat the same peak they leave a horn.
Glossary · Glacial landforms
Hydrograph
A hydrograph plots rainfall then river discharge against time. Rain first; peak later; lag is the catchment’s delay. A flashy basin peaks soon; a rural basin delays. The Spanish-labelled LLUVIA chart is not this lab’s figure — we keep SI units and an English axis. A flood is the peak you can walk; the graph is the same event as numbers.
Glossary · Storm hydrograph
Spit
A spit is a ridge of sand or shingle built by longshore drift with a free end in open water. Spurn Head off Holderness is the UK case; it is till-fed, not chalk. A tombolo joins an island; a spit does not. Groynes interrupt the same conveyor — they do not invent a new sediment budget.
Glossary · Coasts
Stack
A stack is a pillar of the same cliff rock left after a cave became an arch and the roof fell. Old Harry and Durdle Door’s neighbours are chalk versions; they are not sand dunes. Cave–arch–stack–stump is one rock, one budget, four stages. Holderness till rarely lasts long enough to make a textbook stack.
Glossary · Coasts
Terminator
The terminator is the line on Earth between day and night. It walks with axial tilt through the year, which is why polar day and polar night exist. Seasons are that walk, not a changing Earth–Sun distance. Click the 3D Earth on the seasons lab and the terminator is the mesh to name.
Glossary · Why seasons happen
Terminator (day–night)
The terminator is the line on Earth between day and night. It walks with axial tilt through the year, which is why polar day and polar night exist. Seasons are that walk, not a changing Earth–Sun distance. Click the 3D Earth on the seasons lab and the terminator is the mesh to name.
Glossary · Why seasons happen

Places · 7

Case studies · 5

Paths · 3

Tools · 4

Teacher notes · 3