Skeptics with a K: Episode #238


Tearing apples, parole hearings, social media, and judicial reviews. Plus brightening lamps, magic soap, laddered tights, and conspiracy theories. With a big announcement, it’s Skeptics with a K.

If you need to skip through Emma’s discussion about sex offenders, it runs from 0:45:00 to 1:08:10.

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  1. #1 by Nicole Carmody on November 30, 2018 - 01:22

    Alice asked about how to stop headphones from snagging on doors, etc. I’m assuming earbuds? What works wonders for me is running the wire underneath a shirt or jacket behind my back. No snags, the wiree is long enough to carry the device in a front or back pocket. Best part is that if you don’t want them in your ears for a time, you can just drape them over your shoulders and they tend to stay there.

  2. #2 by Nicole Carmody on November 30, 2018 - 01:23

    Alice asked about how to stop headphones from snagging on doors, etc. I’m assuming earbuds? What works wonders for me is running the wire underneath a shirt or jacket behind my back. No snags, the wire is long enough to carry the device in a front or back pocket. Best part is that if you don’t want them in your ears for a time, you can just drape them over your shoulders and they tend to stay there.

  3. #3 by john r lee on November 30, 2018 - 08:00

    Bob Mortimer can tear an apple in half. He demonstrated and explained it fairly well on “would I lie to you?”, the panel show. it was season eleven, one of the later shows, I think. — a fan from across the pond.

  4. #4 by Cappy Charlie on December 4, 2018 - 16:06

    As always an intelligent and reasoned contribution from Emma on a subject that often reduces other podcasts to pearl clutching and name calling. Refreshing to hear an informed voice given the opportunity to speak on such an emotionally charged topic.

  5. #5 by Hugh Manity on December 15, 2018 - 09:39

    One reason to wrap the wire of your IEM (in ear monitor) headphones behind your ear is to cut down on microphonics. If you have the type of earbuds that form a sound reducing seal by going down into the ear canal, then you’ve certainly noticed the thump-thump-thump the wire makes every time it bangs against you while your moving around. Wrapping the wire behind your ear prevents that.

  6. #6 by Ian on January 7, 2019 - 19:43

    I know that Numberphile episode you were referring to, and you were fully correct not to buy it, as it is not true. 1 + 2 + 3 + … does not actually add up to -1/12, and the reason it did for him is that he used an illegal technique at a certain point – it’s like one of those “proofs” that 0 = 1 which “work” by having a hidden division by 0. Amazingly it’s not any of the series manipulations, those are perfectly kosher. The illegal bit happens the moment he writes this (going from memory, he could have written it the other way around):

    S = 1 + 2 + 3 + …

    “But he hasn’t even done anything yet!” – that’s the interesting thing, he does do something here just by writing it out like that, which is explicitely state that the infinite series on the right DOES add up to something (that something being S), even though it doesn’t. You’ve already got a falsehood and from there you can get anything you want, even using perfectly legal techniques. Like the aforementioned 0 = 1, using the same operations he did:

    S = 1 + 2 + 3 + … //shift

    S = 0 + 1 + 2 + … //substract from above by sides

    0 = 1 + 1 + 1 + … //shift

    0 = 0 + 1 + 1 + … //substract from above by sides

    0 = 1 + 0 + 0 + … //add up the 0+0+… part

    0 = 1

    This is my own takedown of the video, but there’s more of them out there, including some quite excellent ones, though it’s been a while meaning I can’t recall the one to recommend. It had a lot of views so it shouldn’t be hard to find. The main Numberphile guy is a physicist rather than a mathematician, as I understand, so he might not be aware that what he’s actually presented is proof-by-contradiction that 1+2+3+… doesn’t add up to anything, rather than proof that it does add up to -1/12.

    His presumed physics background would also explain why he would have though this way, too. There’s actually a function taking infinite sequences and producing real numbers as a result which gives the sum of the series made from those numbers when such a thing exists (so f(1, ½, ¼, …) = 1 + ½ + ¼ + … = 2, for example), but which also produces results after being fed sequences whose series would diverge. The function behaves roughly the way he demonstrated his “series” to behave, so indeed f(1,2,3,…) = -1/12. It’s useful in some physics calculations as I understand, hence the physicist background reference. I can’t tell you more detail here, as I’ve not investigated further.

  7. #7 by Ian on May 25, 2019 - 06:29

    Youtube recommendations decided to serve the takedown I had in mind to me again for some reason, so here you go – enjoy the big math diss track of 2018: https://www.youtube.com/watch?v=YuIIjLr6vUA

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