Everything in the catalog

Explores fractions with shapes, number lines and matching games.

Feeds numbers or pictures through a function machine to infer the rule.

Pumps gas into a container to explore pressure, volume and temperature relations.

Shows how slope and intercept shape a line, with challenges for slope-intercept and point-slope forms.

Simulates orbiting bodies such as Sun, Earth and Moon so you can change masses and watch paths.

Shows how greenhouse gases change the energy balance of the atmosphere.

Stretches springs to show force, displacement and spring constant relations.

Hangs masses on springs to study oscillation, spring constant and energy.

Mixes solute and solvent to see how concentration, volume and moles relate.

Adjusts electronegativity to see bond dipoles and molecular polarity.

Simulates a bunny population with mutations and selective pressures over generations.

Shows normal modes of coupled masses on springs.

Shows how voltage and resistance change current in a simple circuit with adjustable sliders.

Swings one or two pendulums with adjustable length, mass and gravity and graphs the period.

Measures pH of everyday liquids and shows how concentration changes with dilution.

Drops balls through pegs to show how random bounces build a binomial distribution.

Fires objects from a cannon with adjustable angle, speed and drag to study trajectories.

Compares paint mixes and necklaces to explore ratios and proportional reasoning.

Sliders for resistivity, length and area show how each one changes a wire's resistance equation.

Shows molecules of different substances as temperature and pressure change.

Adds vectors graphically and shows their components and sum.

Wiggles a string to study wave speed, damping and reflection.

Runs Prettier on pasted code with adjustable options and shows the formatted result.

Build optical setups from lenses, mirrors and sources and trace the rays in the browser.