Video: https://www.tiktok.com/@distilledscience/video/7540018048330190111
Transcript
Was Dash from the Incredibles actually running fast enough to run on water? According to physics? And how fast was he running? What about the flash from the current TV show? I built up enough speed to run up a building. How fast do I need to go to run on water? Assuming your weight, 450 pounds of force per step for vertical suspension. I'm counting for fluid drag. Approximately 650 miles an hour. That's some impressive mental math there, Dr. Definitely Not Evil. But was it accurate? Scientists have studied this. Because nerds can be awesome. Harvard researchers back in 96 a model based on the Basilis Glizzard, which actually does run on water. For humans, the key parameters are weight, foot size, step frequency, and the depth that each step pushes into the water. The force comes both from the foot's initial slap against the water's surface tension, and then from the foot stroke through the water. The original researcher has used a step frequency taken from a normal human sprinter, roughly four steps per second. But this is flash or dash, so let's remove that limit. I use data from Usain Bolt and Tyson Gate as a starting point to go from step frequency to running speed. So after some boring mathematics, we get to the first. the minimum speed the foot needs to hit the water at of 27 meters per second, or around 60 miles per hour. Not as much as you would expect, but maintaining that speed through the water would require 14 times a human's normal power output. That's flashed. But what about Dash? With less weight, smaller feet, and more steps to cover ground, he can manage a bit slower than Barry. But still half again as fast as Usain Bolt's record, with way more power. And how fast was he going in the movie? See? Let's see. camera with 10 frames per second, and him traveling roughly 25 feet to and from the desk. He'd have to move at 500 feet per second to not have been caught by that security camera. That's 341 miles per hour, with insane acceleration. So yeah, this checks out. Got any more movie science questions? Ask them down below and follow for more.
Additional notes
What’s another movie you’d like to see analyzed? #science #incredibles #physics #stem #edutok
References
- Harvard 1996 water-running/basilisk-lizard model discussed in transcript; title/source URL/DOI/PMID not listed in workbook.
- Usain Bolt and Tyson Gay running data mentioned in transcript; direct sources not listed in workbook.