Tacoma Narrows Bridge, Tacoma, Youtube discussed on The Skeptics' Guide to the Universe


Let's get back to the show. Let's see if I have time for a couple of questions this week. The first one comes from San Jose, California. Scott necks is Nim. And. Access. Howdy. Fellow skeptics an episode six ninety five you mentioned the claps Tacoma of the Tacoma narrows bridge and recommended listeners look up the footage on YouTube. I did. So in the first thing I noticed that the bridge is only two lanes wide. So Eddie, a quote unquote couple of lanes to the original Zayn couldn't have led to the collapse. I kept digging it found a couple sources that positive ultimate cause for the bridges demise the bridge collapse due aero aero elastic flutter area listed flutter is a separate phenomenon from forced resonance, the YouTube channel, practical engineering is a great video on the subject. Why the Tacoma narrows bridge collapsed. I got a bunch of emails about this. And I did look into it a lot deeper. So this is one of those things where I didn't prep this. It was just sort of an off the cuff comment that I was going based upon what I had previously learned about the Tacoma narrows preserve to to recap. This was hate when we do that. I know it's hard. It's that's the risk of unscripted. And it's a live show, you she all look it up. If something comes up sort of look it up in real time. So that's the risk is elevated when you're doing the live stage show like that. But any case the Tacoma narrows bridge collapsed on November seventh so today, actually nineteen forty. Wow. By coincidence. Odds. It turns out to famous example in physics textbooks. Which is where I I learned about it and the text books get it wrong. So I was actually taught wrong about it. And I was just perpetuating that incorrect. Science textbook fallacy. So it's often presented as a case of forced residents. You have residents in different types of motion open dad versus torsion that magnifies increases the energy until the collapsed. Turns out the actual physics or complicated than that. So although there is some residents going on resonance is happening in the complicated. Physics of what happened to the bridge. And there also was a redesigned. So I I was wrong about what the redesign was. But there was a redesigned at one point, but the redesign which for saving money, the of ritual design would have cost eleven million dollars. And they said, hey. We're just going to replace these trusses with these plate girders, and that will drop the cost down to eight million dollars. And they didn't anticipate or try to figure out how that was going to affect the physics of the bridge. So what happened was from the.

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