11 ms·
Round Peg in a Square Hole [video]
- kamranjon 9y agoso cool - I also like the term 'ambient 3rd dimension'
- jedimastert 9y agoI like it too. I might have to find a way to write about the "ambient 4th dimension" that is time.
- fjsolwmv 9y agoThe magicians trick of "levitating" an object by moving the invisible support to avoid hitting the hula hoop that tests for supports, is using ambient 4th dimensions.
- wereHamster 9y agoBut let's not hijack a perfectly well understood technical term and give it another meaning. "isomorphism" in the javascript community, I'm looking at you.
- ape4 9y agoPrograms do well defined things in their space but are sometimes aware of stuff outside their space - eg if another program slows down the machine exposing a timing bug in the first program.
- OskarS 9y agoI love Tadashi Tokieda so much, he's just one of the most delightful human beings I've ever seen. I highly recommend all of his Numberphile videos, and you should also check out his Toy Models lecture [1]. It's so much fun to see him show some weird phenomenon with marbles or magnets or whatever (that should be seemingly simple to explain with mathematics and/or classical physics) and then say "There is no theory for this. We have no idea why this happens. I'm working on it though". [1]: https://www.youtube.com/watch?v=pkfDYOZ1p4Y https://www.youtube.com/watch?v=pkfDYOZ1p4Y
- Waterluvian 9y agoHe's also got the wonderful pairing of both a smooth ear butter voice and the talent of communicating well.
- luisb 9y agoTadashi is awesome! I love his video explaining how someone found a prime that looks like the Arms of Trinity Hall [1]. Highly recommend all videos from Numberphile [2] and Fermat's Library [3]. [1]https://www.youtube.com/watch?v=fQQ8IiTWHhg https://www.youtube.com/watch?v=fQQ8IiTWHhg [2]https://www.youtube.com/channel/UCoxcjq-8xIDTYp3uz647V5A https://www.youtube.com/channel/UCoxcjq-8xIDTYp3uz647V5A [3]https://www.youtube.com/channel/UCSD2RxaYn2Nxkm41gp-eKfA https://www.youtube.com/channel/UCSD2RxaYn2Nxkm41gp-eKfA
- imglorp 9y agoIf you aren't convinced rolling downhill is complicated, physicist Walter Lewin has a demonstration involving cylinders, no fluids this time. https://www.youtube.com/watch?v=cB8GNQuyMPc https://www.youtube.com/watch?v=cB8GNQuyMPc
- arbie 9y agoThat was incredible. Every combination hypothesized, then experimented with, ending with an intuitive explanation.
- lisper 9y agoI'm afraid I have to dissent here. Compare the footage at 2:10-2:15 with that at 3:20-3:25. He wants the result to be that the box starts sliding at the same angle in both cases, and that's what should happen if what they teach in physics 101 is correct, but that is not actually what happens in the video. In fact, the box starts to slide noticeably earlier in the second case (which is exactly what the off-screen crew members predicted). But he simply glosses over this and says "within one degree the same". What is what should have happened, but is not what actually happened. This is a very unscientific attitude, and I think this does a tremendous amount of damage to the popularization of science, particularly in the face of accusations that science is just another religion with its own dogmas, high-priesthood, etc. The correct reaction here would have been, "Hm, that's interesting, it started sliding earlier. That's not what I expected, and is not what theory predicts. Let's see if we can figure out why this happened." It's also kind of lame that we have to rely on his callouts to know what angle the board is at. It would have been trivial to set up a pointer that would have been visible to the camera. P.S. Yes, I know that he "explains" the discrepancy at 3:40, but his explanation is bogus. First, the discrepancy is much bigger than the "half a degree" that he explains away. And second, his explanation is actually a hypothesis that is easily tested: just run the experiment multiple times. He could easily have done this and again demonstrated how science is actually supposed to work, but he didn't. P.P.S. He does it again at 7:02 where the longer cylinder is clearly beating the shorter one by nearly a full cylinder radius right before he proclaims "no difference".
- sillysaurus3 9y agoI wish HN would loosen up and admit that videos are a new medium, worth taking seriously. It might bother us that longform writing is dying, but when the new generation decides that this is the way new ideas should be communicated, we'll be left with no audience. For example, I've been working on an essay for some time now, but I'm seriously considering making it into a companion video. I have no video experience whatsoever, so that's a tall order. But what are you to do? If you want to make an impact, are you sure it's still possible to do it by writing 173 essays over 15 years? It used to be, but the world seems to be changing. (This is mostly a reaction to this post being one of the rare videos Deemed Worthy to be on the front page, when there are tens of thousands of others. It's not a good idea to mix up the content too much, but there really are a lot of quality videos and no central curation mechanism. Unlike articles. /r/videos is for mainstream content, like https://youtu.be/kJGGlVg5PpY https://youtu.be/kJGGlVg5PpY. There really isn't any place that collects intellectually gratifying content like the current submission.)
- philfrasty 9y agoPersonally I can learn MUCH faster (+ enjoying it) by looking at someone doing/explaining something in a video (e.g. coding). To take it even further: if one person (expert) explains something to another person (not an expert on this specific topic) and the non-expert frequently aks questions. This helps tremendously.
- jscharlack 9y agoAgreed though it depends on the topic. If it's very visual, like this is, video is perfect. Video makes a lousy reference though.
- stochastic_monk 9y agoI typically don’t have the patience for most videos. I want information, and much of the time, the information bandwidth or payoff is too low. I think video can be great auxiliary, supporting material, but there should usually be a textual component when trying to inform.
- wolfgke 9y agoTo me this is not very surprising to me, since in Germany there exists a well-known children's game called "Durch eine Postkarte steigen" ("step through a postcard"), where - as the naming suggests - you have to step through a postcard while you are only allowed to use scissors to cut the postcard in a clever way. Here a German YouTube video that shows how it is done (you don't have to understand anything that is spoken, since I think the video is quite self-explanatory): > https://www.youtube.com/watch?v=ynoLSTsrRhs https://www.youtube.com/watch?v=ynoLSTsrRhs
- Dangeranger 9y agoChildren in the USA play that game as well, but the moment when he shows that the gap in the 2D space is expanded to the two sides of the square by folding into 3D space is still amazing. I screamed out loud it was so much fun to see.
- dandare 9y agoI think that is a different principle.
- wolfgke 9y ago> I think that is a different principle. I don't think so. In both cases we have some object with the property that the "perimeter of the convex hull of a 2D projection of it" is too large to fit the object through some hole in the paper. On the other hand, the length of the border of the hole in the paper is at least as large as this perimeter. So we twist the paper around such that the object passes through.
- cortesoft 9y agoMr. Wizard had an episode where he did this same thing: https://www.youtube.com/watch?v=LjAboqBeGpE https://www.youtube.com/watch?v=LjAboqBeGpE
- jonshariat 9y agoI think the reason the example in the video is so interesting is that its non-destructive. It only involves bending and the paper and coaster remain intact.
- thegabez 9y agoGoes to show how poorly adapted our intuition is in manipulating space across dimensions. Its scary to think about how much ground breaking science is still left uncovered because of this blindspot.
- tw1010 9y agoWhile you're definitely onto something, I think it's also worth pointing out that a lot of the scientists that really revolutionized their field were those who excelled at either intuitively or explicitly tackling the areas where human intuition was especially likely of doing poorly on (which in many cases acts as a good proxy for assumptions that other scientists have, in an unknown unknown sense, failed to question).
- thegabez 9y ago100% - This would make for an exciting opening lecture for any scientific educator.
- joenathanone 9y agoThe only thing I found surprising about this was that you were expected not to have known how it worked. It's the same sort of thing as trying to move a couch and having to angle it to fit it through a door, it's how 3D space works.
- 2bitencryption 9y agoyou're so smart!
- itg 9y agoI think the equivalent would be a door that is too small now matter what angle the couch is in. The only way to get it through would be to "stretch" the door in 4-d space and collapse it back into 3-d to allow the couch through.
- simooooo 9y agoThank you for using your intelligence to give us such insight
- neogodless 9y agoAhhh Easter Egg! Firmware version! Love it!
- IshKebab 9y agoThought this was going to get clever but... it didn't.
- Slansitartop 9y agoGreat video, but I think it would have been better without the cartoons. They were distracting and added nothing.
- will_dev_4_food 9y agoCould you be so kind as to provide a non YouTube link for this? Sites that don’t honor the 1st Amendment are blocked on my devices. Thanks.
- andr 9y agoYou probably know that already, but the First Amendment does not apply to private companies.
- will_dev_4_food 9y agoUnless they represent what is classified as a utility. How to classify a utility? Ask what would be nigh impossible without it.
- will_dev_4_food 9y agoOn the other hand, I suppose having big tech act as the ministry of truth is great, as long as you’re on the top of big tech.
- hexane360 9y agoDo you own a website? I have some files I'd like to publish on it. You do honor the 1st Amendment, right?
- will_dev_4_food 9y agoI’m not a functioning utility, but when I get there, yes.
- will_dev_4_food 9y agoI do. And I will honor all requests of the CIA to your metadata. Still ok?
- tomtimtall 9y agoYou can fit any object at any size through a an arbitrarily small and arbitrarily shaped hole. Just blend it an send it through as a stream with the same cross section as the hole. The naysaers will say that this is cheating because you are changing the shape of the object, but the trick mentioned here is just changing the shape of the hole from a square of one perimeter length into a rectangle with the same perimeter length. Similar yet simpler trick for those who don’t have a blendtec ready at hand.
- ghostwreck 9y agoIf you like the idea of solving problems using extra dimensions, Diaspora [1] takes the idea in some really interesting directions. Just be prepared to fight through a few sections of intense Riemannian geometry to bring you into that world. [1]: https://en.wikipedia.org/wiki/Diaspora_(novel) https://en.wikipedia.org/wiki/Diaspora_(novel)
- mirimir 9y agoThis is probably my favorite novel by Greg Egan. Most of its central characters are AIs.
- Starwatcher2001 9y agoLove it. It's stuff like this that got me interested in science. I remember seeing the same thing (larger object through a smaller hole) demonstrated on "How" in the 1970s, which was a TV show with a quirky mixture of science and fun. It was aimed at children, but didn't talk down to them. Here's a ransom episode for those who remember that show. https://www.youtube.com/watch?v=rsDd_9VpzHE https://www.youtube.com/watch?v=rsDd_9VpzHE
- sackeyj1 9y agoDidn't think I'd really be that interested in this. Kind of made me excited. Thanks.
- andy_ppp 9y agoI think about the analogy of folding spacetime when I see things like this... what could you used to fold a 4d region of spacetime into a fifth dimension to create a “wormhole” and where would it lead? I’m not even sure what this would mean!
- aidos 9y agoSomeone posted this in a comment on HN during the week and I subscribed immediately. Soooo wonderful. I'm definitely going to give this a shot with the kids tomorrow. Thanks for reminding me.
- jonplackett 9y agoNever heard of Tadashi Tokieda before so THANKS!
- runeks 9y agoSeems obvious to me: you have a square with four sides of length n, and when you fold the paper, the four-sided square with a circumference of 4n becomes a slit of length 2n.