Why a dam is fat at the bottom: water's push grows with depth squared, its tipping with depth cubed
30seconds
A dam is fat at the bottom and slim at the top because water pressure grows with depth, so the push grows with depth squared and the tipping effect with depth cubed.
Drag the water level, switch between a wall and a wedge, and change the base width to see when a dam tips about its toe. Then see why a wedge needs about 40% less concrete than a wall, and how Hoover Dam's 660 ft base fits the same idea.
Deep dive · 5 min
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