Water Parabola - Physics Demonstrations - Water Parabola | Physics Undergraduate Labs

Verify that the glass cylinder is firmly secured to the rotation platform before operation. An improperly mounted cylinder could detach during rotation, creating a safety hazard.

Purpose

A water-filled glass cylinder spun on a centrifugal machine produces a parabolic free surface. Students see that the equilibrium shape results from the balance of gravitational and centrifugal forces in the rotating frame, with the curvature depending on rotation rate.

Tall cylindrical glass vessel containing water, photographed against a dark background, showing a concave parabolic surface at the top of the water column

Glass cylinder mounted on a centrifugal machine with hand crank and belt drive, positioned in front of a black backdrop, with a desk lamp to the right

Figure 1: The rotating water column displays the characteristic parabolic surface shape.

Figure 2: Complete apparatus: glass cylinder on centrifugal machine with black backdrop for contrast.

Rotatable Glass Vessel

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Pitcher

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Centrifugal Machine

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Safety Warnings

Warning: Mechanical Stability

Purpose