Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For Students · Interferometer

Interferometer for planetary motion

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate planetary motion live below — adjust the inputs and watch it respond, right in your browser.

Wave Interference

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Wave Interference StudioLive

two-source interference · ripple tank

Controls

Speed1×

Two point sources emit circular waves — where they meet, you see constructive and destructive interference fringes. Drag either source on the canvas to reposition it and watch the pattern update live.

Presets

Frequency

Source separation

▶ Run in Python

Data Inspector

Sources2

Grid220×220

Wavelength15.7 px

Separation100 px

Patterninterference fringes

Governing equation

y = A_{1} sin (k r_{1} - ω t) + A_{2} sin (k r_{2} - ω t), Δ r = mλ, λ \approx 15.7 px, Δ s = 100 px

Reading this result: Wavelength is about 15.7 px and the two sources sit 100 px apart. Bright fringes appear where the path difference to the two sources equals a whole number of wavelengths (constructive interference); dark fringes fall halfway between, where the difference is a half-wavelength (destructive interference). Shrinking the wavelength or widening the separation would pack more fringes into the same space.

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Double Slit

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Double-Slit ExperimentLive

wave interference + diffraction

Controls

The iconic experiment: two slits create interference fringes, modulated by each slit's diffraction envelope.

Presets

Slit separation d

Slit width a

Wavelength λ

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Data Inspector

Fringe spacing∝ λ/d

Envelope∝ λ/a

Regimeinterference-dominated

Governing equation

I = I_{0} cos^{2} \frac{π d sin θ}{λ} sinc^{2} \frac{π a sin θ}{λ}, Δ y = \frac{λ L}{d} = \frac{20 \cdot 800}{40} = 400

Reading this result: Two-slit interference sets the fine fringe spacing (∝ λ/d) while single-slit diffraction sets the envelope (∝ λ/a); here about 10 bright fringes fit under the central peak.

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Single Slit

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Single-Slit DiffractionLive

light bending around edges

Controls

Presets

Slit width (µm)

Wavelength (nm)

Send light through a narrow slit and it fans out into a bright central band flanked by dimmer fringes — diffraction. The pattern follows a sinc-squared curve, with the first dark fringe where the path difference across the slit equals one wavelength. Narrower slits spread the light more, the diffraction limit that caps every lens and telescope's sharpness.

▶ Run in Python

Data Inspector

First minimum1.6°

Central width3.2°

Slit/λ36.4

Governing equation

I = I_{0} sinc^{2} β, β = \frac{π a sin θ}{λ}, a = 20 μ m, λ = 550 nm

Reading this result: Wide slit relative to the wavelength: the central peak is tight and the beam stays nearly collimated, with only faint fringes.

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More with Interferometer

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Frequently asked questions

Is this good for students?: Yes — this version of "Interferometer for planetary motion" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.