4 ms·
Why does paper fold so well?
- zeristor 4mo agoA lovely little podcast on paper physics for origami.
- borutz 4mo agoNice old video about this: https://www.youtube.com/watch?v=EKEavnS10HI https://www.youtube.com/watch?v=EKEavnS10HI
- aequitas 4mo agoThe Mythbusters proved you can fold it up all the way to 11: https://www.youtube.com/watch?v=65Qzc3_NtGs https://www.youtube.com/watch?v=65Qzc3_NtGs
- sampo 4mo agoIt was this paper folding video (and the guy's unapologetic Finnish accent) that launched Hydraulic Press Channel to fame. https://www.youtube.com/watch?v=KuG_CeEZV6w https://www.youtube.com/watch?v=KuG_CeEZV6w
- yread 4mo agoAnd why does it sink. Its basically squished wood!
- deleted 4mo ago[deleted]
- OJFord 4mo agoI really can't imagine getting paper to sink any more easily than wood?
- RetroTechie 4mo agoTry toilet paper. Let it into the water vertically as to not catch air pockets.
- IAmBroom 4mo agoIt floats, unless it is burdened with matter. Even when fully wet.
- tobyhinloopen 4mo agoBecause the air is squished out I suppose
- flybrand 4mo agobecause the fibers are denser than wood and hydrophilic - so the pockets between the fibers fill with water that displaces the air. Air pockets become water pockets = neutral. Fibers denser than water = sink.
- srean 4mo agoOh no! woe is me, they don't highlight my absolutely, ridiculously favourite fact/curiosity about a sheet of smooth paper: If you fold it clean, the crease is a straight line. In fact I don't know of any other good way of obtaining a straight edge from scratch quickly, meaning without transporting one existing straight edge to another (*). I remember spending a lot of enamored time coming up with different geometrical proofs of this fact. Perhaps the only time I have come close to jumping out of the proverbial bath tub. The underlying reason is that paper does not stretch (**) (but, paradoxically, it does bend fine. It's a paradox because bending needs stretching). I have to restrain myself from grabbing strangers off the streets to ask -- how cool is that. Three other demonstrations that never fail to nerd-snipe me like this are Dirac's belt trick, that straight woven cloth rips usually at 90 degrees, and the working of a teeny tiny metacircular interpreter. (*) Rope stretching is a close competitor, but the tension needs to be really really high and it is difficult to run a pencil along it to mark a straight line, lest you distort the st. line. (**) of course, it does, but a tiny amount. Coming back to straight line folds, this property holds beyond just Euclidean space, it holds for Riemannian geometry and probably for any continuous metric space.
- arijun 4mo ago> The underlying reason is that paper does not stretch I don't think that's sufficient--tinfoil doesn't stretch, but it doesn't fold nearly as neatly as paper.
- srean 4mo agoYou are perhaps commenting about the force needed to fold, the persistence of the folded shape. My comment is about the shape of the crease once it has been folded. Most metals are stretchier than paper. If it is thick it will resist folding, but once you have folded it, that is, the two flat boundary surfaces have coincided, the crease would be a straight line if the surfaces cannot stretch. How much force you will need to exert to form a fold depends on material properties but the geometrical nature of the crease is dictated by stretching.
- qsera 4mo ago"Paper folds in a straight line" and I was like "duh! what else?" Until I read this comment, and it bought back all the memories where I tried to fold other things like plastic sheets and tin foils and how they never ended in straight line...damn. I never noticed...
- arijun 4mo agoUnless I'm missing a transcript somewhere, this is missing an [audio] tag.
- mixseo 4mo ago[dead]
- leebeef 4mo agoThis is exactly the sort of hard-hitting journalism that makes me proud to pay my TV licence.
- tomalpha 4mo agoIt’s always hard to tell whether a comment like this is supportive or sarcastic so this is either me agreeing or disagreeing with you… For me this kind of simple, straightforward, educational content is part of the reason I’m proud to pay my TV licence.
- ern 4mo agoI'm not from the UK, but the soft power of BBC Radio 4 in the late 90s and early 2000s (the Real Player era) made the UK seem like an advanced nation to my young and intellectually curious self. If lived in the UK at the time, I'd have been immensely proud of the quality of the programming.
- deleted 4mo ago[deleted]
- Peterz_shu 4mo agoIt has a lot of air gaps within its fibers. We know that Solids CANNOT be compressed. So what's actually being folded is the air gaps. Which is why you can't easily fold a piece of tungsten. It has less air gaps.
- gruez 4mo agoBut you can fold aluminum foil just fine? That certainly doesn't have "a lot of air gaps within its fiber"
- dotancohen 4mo agoActually I've never had success cleanly folding aluminium foil. There are always imperfections and creases.
- IAmBroom 4mo agoPretty sure the material's innate stiffness plays a role there, too. Metallic film folds quite nicely.
- fuzzythinker 4mo agoShameless plug - https://foldmation.com https://foldmation.com Big backlog of folds to approve seems like it's ignored. I'm in the middle of fixing some rendering issues hence I haven't approve them yet. Rendering fixes and fold approvals should be up in a few weeks.
- letstools 4mo ago[flagged]