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Sandbox Physics

OPEN LABZH / ENNO INSTALL

Change one condition.See the law respond.

Every experiment is an independently runnable physical system. Adjust its initial state, interaction, or boundary conditions, then use equations to explain what you actually observe.

25
runnable experiments
4
physics domains
2
languages

FIELD NOTE · 2026 FIELDS MEDAL

One box, three worlds

Yu Deng’s work did not discover that gas particles collide. It proved that Newton’s laws for individual hard spheres can reach Boltzmann’s statistical world over long times.

Understand the story, then run the model
01 / EXPERIMENT DOMAINS

Choose a system first.
Then ask what law it follows.

Motion, waves, fields, matter, and quantum states use different descriptive languages, but every entry point is the same: change a controllable quantity, read the response, and check what is conserved, propagated, or transformed.

01DYNAMICS

How a state evolves through time

Motion & dynamical systems

observe trajectories and invariantsdpdt=F\frac{d\mathbf p}{dt}=\mathbf F

Start from an initial state and let forces and constraints determine the next moment. Read orbits, oscillation, chaos, and many-body motion.

6 experiments
  1. 01

    Chaos · nonlinear dynamics

    Double Pendulum & Chaos

    How long can nearly identical starts share one trajectory?
    key concepts

    nonlinear dynamicssensitivityenergy

  2. 02

    Gravity · central forces

    How Orbits Take Shape

    How can one force law draw three different conic sections?
    key concepts

    inverse-square forceangular momentumconics

  3. 03

    Mechanics · normal modes

    How Coupled Springs Move Together

    Can collective motion be decomposed into clean modes?
    key concepts

    normal modescouplingbeats

  4. 04

    Relativistic astrophysics · multi-messenger astronomy

    Binary Neutron Star Merger

    How does a rising chirp foretell tidal collision, kilonova ejecta, and a compact remnant?
    key concepts

    gravitational wavescompact binariesmulti-messenger astronomy

  5. 05

    General relativity · gravitational lensing

    How a Black Hole Bends Light

    Why can one thin accretion disk appear both above and below the black-hole shadow?
    key concepts

    gravitational lensingnull geodesicsblack-hole shadow

  6. 06

    Gravity · chaos

    The Three-Body Dance

    Why does one extra body remove the general orbit formula?
    key concepts

    many-body gravityperiodic solutionschaos

02WAVES

Superposition, propagation, and boundaries

Waves & optics

observe amplitude and phase2ψt2=c22ψ\frac{\partial^2\psi}{\partial t^2}=c^2\nabla^2\psi

Change wavelength, phase, apertures, or media and watch local oscillations propagate into interference, diffraction, and resonance.

8 experiments
  1. 01

    Waves · superposition

    When Two Waves Meet

    Why do passing waves leave a stable fringe pattern?
    key concepts

    superpositionphasepath difference

  2. 02

    Fourier series · rotating vectors

    Draw Any Wave with Circles

    How can steady rotations rebuild almost any periodic signal?
    key concepts

    Fourier seriesspectrumharmonics

  3. 03

    Waves · diffraction

    Light after a Narrow Slit

    Why does a narrower opening spread light farther?
    key concepts

    diffractionapertureintensity

  4. 04

    Optics · ray tracing

    How a Lens Redirects Light

    How do three principal rays locate and size an image?
    key concepts

    refractionfocal lengthimaging

  5. 05

    Gravitational waves · laser interferometry

    Listen to Spacetime with Light

    How can a sub-proton length change become a readable signal?
    key concepts

    interferometrygravitational wavesdark port

  6. 06

    Geometrical optics · two-surface refraction

    Two Refractions inside a Thick Lens

    What does the thin-lens model miss when thickness matters?
    key concepts

    Snell lawprincipal planesspherical refraction

03FIELDS + MATTER

How local interactions create global structure

Fields, fluids & matter

observe fields and distributionsF=U\mathbf F=-\nabla U

Begin with local interactions among charges, particles, and fluids, then read field lines, distributions, pressure, and macroscopic response.

6 experiments
  1. 01

    Fields · electrostatics

    Make an Electric Field Visible

    How does the shape of potential predict the next force?
    key concepts

    potentialgradientfield lines

  2. 02

    Thermodynamics · molecular motion

    Billions of Collisions in a Gas

    How do random collisions become stable macroscopic laws?
    key concepts

    kinetic theorydistributionpressure

  3. 03

    Electromagnetism · Lorentz force

    A Charge Bending through Fields

    How can a magnetic field turn motion without changing speed?
    key concepts

    Lorentz forcecross productdrift

  4. 04

    Fluid dynamics · spinning balls

    Why a Spinning Ball Curves

    How does spin rearrange flow and create a sideways force?
    key concepts

    Magnus forcecirculationfluids

  5. 05

    Yu Deng · 2026 Fields Medal · Hilbert’s sixth problem

    From Hard Spheres to Boltzmann

    How can deterministic collisions be compressed into a reliable kinetic equation while controlling recollision correlations?
    key concepts

    Boltzmann equationcollision historiesBoltzmann–Grad limit

  6. 06

    Nuclear physics · stellar evolution

    How Stars Build Elements up to Iron

    Why does fusion release energy only until nuclei approach iron?
    key concepts

    binding energynucleosynthesisreaction chain

04QUANTUM

How amplitudes become measurable probabilities

Quantum & fields

observe probability and measurementiψt=H^ψi\hbar\frac{\partial\psi}{\partial t}=\hat H\psi

Change state, phase, measurement basis, or occupation and watch continuous amplitudes produce discrete, repeatable statistics.

5 experiments
  1. 01

    Ultracold quantum gas · Cooper pairing

    How Cooper Pairs Condense

    How can a fermion pair evolve continuously from a cloud-wide correlation into a composite bosonic molecule that condenses?
    key concepts

    Cooper pairingBEC–BCS crossoversuperfluid coherence

  2. 02

    Quantum Lab 01 · amplitude and phase

    Rotate a Qubit

    Where does phase hide when Z-basis probabilities stay fixed?
    key concepts

    amplitudephasemeasurement basis

  3. 03

    Quantum Lab 02 · forbidden region and transmission

    Can a Particle Cross an Impossible Wall?

    When classical transmission is zero, why can a quantum detector still click beyond the barrier?
    key concepts

    quantum tunnelingpotential barriermeasurement probability

  4. 04

    Quantum Lab 03 · path amplitudes

    Can One Particle Interfere?

    How do unpredictable hits accumulate into stable fringes?
    key concepts

    path amplitudescoherenceprobability

  5. 05

    Quantum Lab 04 · entry to field theory

    How a Field Becomes Quantized

    How can a continuous field produce discrete particle excitations?
    key concepts

    field modesquantum oscillatoroccupation

STATE → LAW → EVOLUTION → OBSERVATION

A physical law is not decoration.
It has to move the system.

Animation only displays the result. An experiment begins when you change a condition, shift the prediction, and test whether the equation still explains what follows.

Enter the first system