24 days of kitchen oceanography
Each day a new experiement will be posted here. Reveal what is hidden behind the windows by clicking on the arrows below.
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Vortex street
Where do all the vortices come from?
Experiment 9:
We prepare a mixture of water, sugar (to make the water slightly thicker) and silver paint (which makes the currents visible) in a shallow plate, and slowly pull a paint brush through it. This creates swirls and eddies that change depending on how fast we pull the brush.
When water flows around an obstacle, the flow sometimes becomes turbulent. Then it no longer flows evenly behind the obstacle, such as a pillar of a bridge. Instead, it turns in one direction, then in the other. Eddies appear. Instead of a fast current that moves water around a pillar, we represent the same situation by moving the brush as an obstacle through the stagnant water.