This past Sunday a new episode of one of my favorite shows, the Discovery Channel’s MythBusters, aired with an intriguing experiment. Adam and Jaime wanted to test whether or not it was possible to ride a bicycle underwater.
Ever the engineer, I wondered if I could back up their conclusion, that riding a bike underwater was difficult but not impossible (given a flat surface), with physics. Of course, I had to make a few assumptions about coefficients of friction, weights, and volumes, but I think my analysis still elucidates the general principles at work.
What Jamie was fighting against in the MythBusters episode mainly was the buoyant force. A body of water will push up on you with the weight of water that your volume displaces. But, theoretically, Jamie could have added enough weight to his bike to overcome the buoyant force, and make the traction underwater equivalent. However, at some point, Jamie’s legs just wouldn’t be able to move so much weight around (as he found out).
Hey, some people fact check presidential debates, I check the MythBusters.
I fact checked some physics in two other MythBusters episodes here.