Dump enough cornstarch into a swimming pool, and you can walk across the water’s surface. Scientists have now revealed the secret of this YouTube party trick.
When struck by a foot, the particles suspended in the water jam together like snow piling up in front of a snowplow. The compaction forms a hard patch that can push back with the same amount of bone-crushing pressure concentrated at the tip of a high heel, researchers report in the July 12 Nature.
“If you were to punch the suspension, you might break your wrist,” says Scott Waitukaitis, a physicist at the University of Chicago who was inspired to study the goop after watching videos of people running on top of it.
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