Simulations
Change an input and watch the system respond, so the idea lands before the vocabulary does. Each one goes with a lesson.
16 results
1 Foundation
- A tree as a systemSort the 35 components of a tree system — inputs, stores, outputs, flows and processes — then get your own whiteboard copy of the tree and draw the links between them (IB ESS 1.2.1–1.2.4).1.2.1 to 1.2.4Simulation
- A pond as a systemNineteen measured components of a pond, sorted into storages, inputs, outputs and the flows within. The diagram draws itself to scale as you go, so the sediment really is 400 times the carnivores, and the pond turns out to be quietly filling itself in (IB ESS 1.2.3–1.2.8, 1.2.17).1.2.3 to 1.2.17Simulation
- Open, closed and isolated systemsMatter drawn as particles, energy as flowing arrows, and a counter that stops moving the moment you close the boundary. Switch between open, closed and isolated, then try a tree, a drainage basin, Biosphere 2 and the Earth, and watch the same stuff change category as the boundary moves (IB ESS 1.2.5).1.2.5Simulation
- DaisyworldWatson and Lovelock's planet of black and white daisies, beside the same planet with no life. Brighten its sun and watch the daisies hold the temperature steady while the lifeless planet heats by over 50 °C, knock them back and watch it return, then push the sun until the regulation collapses (IB ESS 1.2.8 to 1.2.11).1.2.8 to 1.2.11Simulation
- Feedback loopsToggle between a balancing loop (fox & rabbit) and a reinforcing loop (ice, albedo & temperature) to see how systems self-regulate or amplify change.1.2.10, 1.2.11Simulation
3 Biodiversity and conservation
4 Water
- Will it mix?Cool the surface of Lake Geneva and watch how deep the water turns over. Mixing depth holds up, then collapses. Find the point where the answer changes, then press Ocean and watch the carbon sink fail the same way.4.1.7, 4.1.8Simulation
- Hold, stir or sink?Set the temperature and salinity of a surface layer and the deep water under it, add wind, and find out which of three things happens: the layers hold, the wind stirs them, or the surface has become denser and sinks. The densities are real ones from TEOS-10, so fresh water turns out to be densest at 4 °C and salt water never gets the chance (IB ESS 4.1.10 to 4.1.12).4.1.10 to 4.1.12Simulation
- Eutrophication: a systems modelNutrients in, phytoplankton bloom, decomposition strips the dissolved oxygen and aquatic life suffocates — the positive feedback loop drawn as a stock-and-flow diagram, with green/red arrows for the polarity of each link (IB ESS 4.4.5–4.4.6).4.4.5, 4.4.6Diagram
5 Land
- Construct a soil systems diagramTwo storages and two flows that belong to the soil system, in a blank box: the kind of question few answered well in May 2026. Build it to exam standard, with arrows that must start and end somewhere, then submit once and see the mark (IB ESS 5.1.8).5.1.8Simulation
- Soil texture and productivityMix sand, silt, clay and humus and watch the four properties that decide how well plants grow. The clay that holds the nutrients is the clay that stops the soil draining, so every soil is a trade-off and one weak property drags the whole thing down (IB ESS 5.1.12–5.1.13).5.1.12, 5.1.13Simulation
- Sink, store or source: a soil carbon modelA soil gains carbon from dead organic matter and loses it through decomposition, and only the balance of those two rates decides which of the three it is. Plough a grassland, drain a peat bog, and watch the same model change state (IB ESS 5.1.14).5.1.14Simulation
8 Human populations and urban systems
- A population as a systemBirths and immigration in, deaths and emigration out, and fifty years of the storage in between. Set the three rates and watch natural increase, growth rate and doubling time recalculate, then load Switzerland and find the country whose population is shrinking naturally and growing anyway (IB ESS 8.1.1–8.1.3).8.1.1 to 8.1.3Simulation
- Label an urban systemA finished urban systems diagram with every label missing. Drag food, fuel, waste and heat to the right boxes and arrows, keep out the labels that belong to other systems, and call each flow a transfer or a transformation (IB ESS 8.2.3).8.2.3Simulation
- Lagos as an urban systemTwenty million people, nearly everything they use brought in and nearly everything they discard sent out. Read what goes in and what comes out of Lagos, then build its systems flow diagram from a blank boundary: four storages, three inputs, three outputs, and nothing that belongs outside the city (IB ESS 8.2.3).8.2.3Simulation