Simulations, illustrations and modelling tools for teaching and research. Each is a self-contained web page that runs in the browser: nothing to install, no server, no account. Open one, and use the controls on the page to customise what you see.
An agent-based grassland where nothing about the animals is fixed. Each carries four inherited traits, every trait is a cost as well as a capability, and species arise by mutation and vanish by starvation, predation or bad luck. Watch a world run, or compose your own: founders, landscape, disturbance and walls. A Customise View button chooses what is shown and how fast.
A survey car drives a real street network with a methane analyser on the roof while hidden leaks release gas into a wandering wind. Colour on the ground is the survey's belief about where a leak is, built up reading by reading. Choose the neighbourhood, the weather and the number of passes, hide the true leak positions, and see what a drive-by can and cannot find.
Osmosis from the bottom up: small water balls slip through a membrane, large solute balls bounce off it, and thousands of elastic collisions draw water into the solution until its back-pressure stops the flow. One bounce in slow motion first, then the whole box. Two companion pages unpack the van 't Hoff equation.
A Stella-style stock-and-flow modeller for teaching dynamical systems in ecosystem ecology. Draw pools, fluxes and converters, type the rate equations, predict, then run the coupled differential equations with Euler or Runge-Kutta 4 in the browser. Four built-in examples, from one soil-carbon pool to hares and lynx.