Do I need to install anything?

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

For Educators · Magnus Effect

Magnus Effect for a swimmer's lap

Built for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs. Simulate a swimmer's lap live below — adjust the inputs and watch it respond, right in your browser.

Magnus Effect (Ball Spin)Live

the curve of a free kick

Controls

Speed1×

Presets

Drag the green vector on the pitch to aim the launch (speed + angle), or slide the spin knob on the left rail — the curved trajectory updates live.

Spin (rev/s)

Ball speed (m/s)

Launch angle (°)

A spinning ball drags air around with it, moving faster on one side and slower on the other. The pressure difference pushes the ball sideways — the Magnus force — bending its flight. It is what curves a free kick around a wall, hooks a golf drive, and makes a curveball break. More spin means a sharper curve.

▶ Run in Python

Data Inspector

Spin30 rev/s

Directioncurves down/right

Speed25 m/s

Launch angle0°

Governing equation

F_{M} = \frac{1}{2} ρ C_{L} A v^{2} \propto ω v = 30 \times 25 = 750

Reading this result: Deflection scales with spin times forward speed, so this 30 rev/s at 25 m/s produces a gentle, gradual curve down/right.

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More with Magnus Effect

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Frequently asked questions

Is this good for educators?: Yes — this version of "Magnus Effect for a swimmer's lap" is framed for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.