Coriolis Effect Simulator (2D)

Reference Frame

Rotation

Rotation rate Ω 1.20 rad/s

Latitude φ 45° N

Launch

Initial speed v₀ 2.4 m/s

Launch heading 0°

Ready — set your rotation and launch.

Live Readout

Flight time

0.00 s

Deflection

—

|a_coriolis| = 2·|Ω_eff|·|v|

0.00 m/s²

How it works

In rotating disk mode the ball is launched from the hub and travels in a perfectly straight line as seen from outside the disk (no real horizontal force acts on it). The dashed cyan line is that outside view. The solid path is the same ball's position converted into the disk's own spinning coordinates — from the disk, the ball visibly curves, which is exactly the Coriolis effect: a fictitious deflection that only appears inside a rotating reference frame.

In planetary mode the ball moves across a small patch of a rotating planet at latitude φ. Only the vertical component of the planet's spin twists a local horizontal frame, at rate f = 2Ω·sin(φ). The simulator integrates the real horizontal Coriolis acceleration directly: a = −2Ω×v, which in this local plane reduces to a_x = f·v_y, a_y = −f·v_x. That steady sideways push bends every straight launch into a circular arc (an "inertial circle") — deflecting to the right in the Northern hemisphere (φ > 0) and to the left in the Southern hemisphere (φ < 0), with no deflection at all on the equator (φ = 0) where f = 0.

This is the same force that curves ballistic shells, ocean currents and cyclones on Earth — just isolated here on a flat, frictionless plane so the geometry is easy to see.

Straight-line reference Actual (rotating-frame) path