Mozon
Watershed in the classroom

Two lessons, forty minutes each.

Both run on the free browser demo at play.mozonapp.com or on the Windows app. Students work in pairs at one screen. Print this page for the worksheets; in print the answers are hidden, so the same page serves as the student copy.

Before the lesson

  • Open the demo once on the classroom machines so the terrain tiles are cached.
  • Check that the machine shows "GPU" in the top-left panel. If it shows a warning, the graphics chip has no WebGPU; pair those students with another screen.
  • Sound is off by default. Keep it off in class.
Lesson 1

When England was a peninsula

Geography ยท History ยท ages 13โ€“1640 minutesIdeas: sea level, Ice Age, land bridges, why places are where they are

Learning goals

  • Explain why sea level was about 120 m lower at the Last Glacial Maximum, 20 000 years ago.
  • Predict which shallow seas become land and check the prediction against real depth data.
  • Connect the dry land to how people and animals moved.

Sequence

  1. 5 min, hook. Ask: could you have walked from London to Paris? Collect guesses.
  2. 5 min, set up. Students open Watershed, find the Channel, and in Era scenes press Last Ice Age. The sea slider shows โˆ’120 m. Ask what changed on the map.
  3. 10 min, test the prediction. In Journey, place the start flag at Dover and the destination at Calais. The caravan finds a land route of about 50 km. Students read the days and camps.
  4. 10 min, transfer. Pairs choose one other sea from the list (Persian Gulf, North Sea, Bering Strait, Torres Strait, Adriatic) and repeat: does it dry out at โˆ’120 m? Worksheet questions 3 and 4.
  5. 5 min, drag the slider. Set the sea to โˆ’60 m, then โˆ’250 m, then +70 m (No ice left). Which coastlines are most sensitive, and why?
  6. 5 min, discuss. Where did the first people of Britain come from, and how? Which modern countries would share a land border at the Ice Age that do not today?

Where the numbers come from

Watershed shows real elevation and seafloor data from public surveys. The sea slider recolours everything below the chosen level. This is honest about depth, but coarse about detail: narrow channels a few kilometres wide may be missed. Students should treat a land bridge as "probable", not proven.

Extension

Set the atlas year to 20 000 BC in the Time atlas. Every city disappears. Ask why, and what "city" would have meant then.

Worksheet 1

  1. Why was the sea lower in the Ice Age? Where was the water? Answer: locked in ice sheets on land, kilometres thick over Canada and Scandinavia.
  2. How long is the Dover to Calais walk in Watershed, and how many nights? Answer: about 50 km, 3 days on foot at a caravan's pace.
  3. Your chosen sea: does it become land at โˆ’120 m? Fully, partly, or not at all? Explain using its depth. Answer: Persian Gulf fully (under 90 m deep); North Sea mostly; Bering Strait fully; Adriatic north half; Torres Strait fully.
  4. Name a plant, animal or people that could have crossed your land bridge. Answer: any reasoned example; Bering Strait: the first Americans; Channel: mammoths, hunters.
  5. At +70 m, which large cities today would be under water? Answer: London, New York, Shanghai, Cairo delta, Dhaka, most of the Netherlands.
Lesson 2

Where does the rain go?

Geography ยท Earth science ยท ages 12โ€“1640 minutesIdeas: catchment, watershed, runoff, infiltration, floods

Learning goals

  • Define a watershed and find one on a real mountain.
  • Describe what happens to rain: runoff, ponding, infiltration, evaporation.
  • Explain why the same storm floods one valley and not its neighbour.

Sequence

  1. 5 min, hook. Pour a cup of water on a crumpled sheet of paper. Ask where it went and why.
  2. 5 min, set up. Students open Watershed over a mountain area (suggest the Alps near Interlaken, or a range near your school). Pick Circle, draw a circle about 15 km across, choose the Alpine storm preset, press Start rain, then Play.
  3. 10 min, watch. Water gathers in the lowest lines first. Students sketch the rivers as they appear and mark where the water leaves the area. Read "Where the water goes" on the right.
  4. 10 min, experiment. Reset. Change one thing only: the surface type to Sand / desert (water soaks in), or Urban (water runs off). Same storm. Compare the flooded percentage after the same number of hours. Worksheet questions 3 and 4.
  5. 5 min, probe. Hover over the deepest blue. Read the depth and the ground height. Find the flattest place with the most water.
  6. 5 min, discuss. If you could build one town in this valley, where would you put it, and why not in the flattest spot by the river?

Where the numbers come from

The water is computed live by a shallow-water model on the graphics card, with friction, soaking-in and evaporation set by the surface type. It is a teaching model, honest about direction and order of magnitude, not a flood forecast. Students should not conclude that a real house is safe or unsafe from it.

Extension

Turn on Show vegetation after a long storm at a fast rain clock. Green appears along the water. Ask what a satellite photo of a desert after rain looks like, and why oases are where they are.

Worksheet 2

  1. Draw the area you rained on. Mark with arrows where the water went, and with an X where it left the map. Answer: arrows follow valleys downhill to one or two outlets at the lowest edge.
  2. What is the name for all the land that drains to one river? Answer: its catchment, also called a watershed or drainage basin.
  3. Same storm, sand instead of rock: was more or less of the ground flooded after 4 hours? Why? Answer: less; sand lets water soak in (infiltration), rock does not.
  4. Same storm, urban surface: what happened to the rivers? Answer: they rose faster and higher; paved ground sends almost all rain straight to the streams.
  5. Where would you build your town? Give two reasons. Answer: on a terrace above the valley floor, near but not in the river; flat land by a river floods.
Print both lessons Answers are hidden in print. Licences for a class: info@mozonapp.com