SinkholeShrisha PrakirAward: Top 100
School: north hollywood high school After many takes, flashlight mounted atop my camera, I was able to capture an image of the whirlpool created by water draining from my outdoor sink, a key demonstration of hydrodynamics. A common misconception is that the direction of the vortex is due to the Coriolis Effect, an inertial (fictitious) force exerted on the water by the rotation of the Earth. However, it would take a distribution of mass far larger than what's in my sink, or an absolutely still body of water, in order to reliably demonstrate it. Instead, the direction of the swirl comes from the asymmetry of the sink and random movement of the particles within the stream of water. As it gets closer to the drain, the distance from the axis of rotation of the water decreases, and in turn, reduces the rotational inertia of the water. Angular momentum is a conserved quantity, proportional to both angular velocity and the moment of inertia; Thus, angular speed, and linear speed by extension, must increase in order to compensate for the decreased rotational inertia. And the end result is a pretty cool photo. 
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