Coriolis Effect

This model shows why moving objects appear to curve on a rotating Earth. Seen from outside the ball flies straight, but the turntable under it stands for the turning ground, so the path bends right in the northern hemisphere, left in the southern hemisphere and not at all at the equator. Students set latitude from -90 to 90 degrees and launch speed from 100 to 1000 m/s, show the deflection force arrow and press Launch again. Readouts give the real deflection for a 20 km shot, flight time, Coriolis parameter and the rate the ground turns. It links to weather and ocean currents.

• Set Latitude to 45 and press Launch again, then repeat at -45 and compare the curve direction.
• Set Latitude to 0 and check that the path stays straight.
• Move Latitude to 90 and read the Ground turns at readout.
• Raise Launch speed and watch how the Deflection (20 km shot) value changes.
• Turn Show deflection force off and describe the curve from the path alone.

1. 1Explain that the Coriolis effect comes from Earth's rotation.
2. 2Predict the deflection direction in the northern and southern hemispheres.
3. 3Describe how the effect depends on latitude and is zero at the equator.
4. 4Connect the effect to the spin of hurricanes and the paths of winds.

Questions teachers ask