I started wondering what errors I made in my math, what effects weren't captured, what assumptions don't represent this well... and decided well, it's my Saturday
I'll just re-watch the video.
Because this footage is fascinating.pic.twitter.com/75oX2gvNpj
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...and then I noticed those fuzzy red threads again... They're about the same color as what I originally saw trailing the baseball, and they're *just* blurry/fuzzy enough to not be certain if it's fire or red thread.pic.twitter.com/XAjvno3z0e
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Fast forward to 11:50 in the video. Here's a side-by-side of two different scenarios. The one on the right is the ball that looks like it has a flame (or trailing thread) behind it, and the one of the left has a much more visible disassembly of the stitching+outer layer.pic.twitter.com/Isj4BPNnRE
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Update: thanks to
@lars_0 and@DrChrisCombs for pointing out one error! The 100 deg F was calculated using relative temps instead of absolute temps. Making that correction brings the static temp to 200 deg F and the total temp to 277 deg F behind the shock / in front of ball
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PS, if anyone has ignition data on 100% cotton in air at ~30 psia and 200 deg F conditions, please share. (I'm lookin' at you, spacesuit designers...)
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Not quite the 1:1 data I was hoping to find, but hey, this is just a fun attempt anyways... Thanks to this
@NavyResearchLab doc from 1966 study of materials in hyperbaric atmospheres, there's data on Terry Cloth (closest to cotton here). Ref. https://apps.dtic.mil/sti/pdfs/AD0644556.pdf … (Table 2)pic.twitter.com/WUgRnpTOM3
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Assuming that terry cloth is a good representation of cotton thread for this quick assessment, we see that increasing the pressure to 30 psia reduces the time needed to
However, that ignition delay is much longer than the < 1 sec time it took for the ball to reach the glove.pic.twitter.com/XVZUSFMr0z
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While it's not a solid, smoking-gun solution, given the assumptions and available data, I think my guess here is that the trailing red/orange blur behind the ball (prior to glove impact) is an out-of-focus thread that became liberated due to seam failure. What's your guess?

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Thanks for the awesome videos,
@smartereveryday
Keep it up!
https://www.patreon.com/smartereveryday pic.twitter.com/OaWcaqZ2Np
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En réponse à @megsylhydrazine @smartereveryday1 réponse 0 Retweet 2 j'aime
Le chargement semble prendre du temps.
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