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Why soda bottles have gaps in their threads (2000)
- leephillips 5y agoHats off to Tony Smith, a stand-up fellow.
- EdwardDiego 5y agoMy country's national library used to provide a service in the 70s/80s where you could send a letter or telegram with a question, any question, and they'd do their best to answer it. My Mum was a big fan of it, I've still got a copy of their telegram response to her question of "Why don't we see birds flying overhead with a penis flopping around?" The answer was simple. "Most birds don't have penises. They press cloaca to cloaca. Birds that do have penises store them in their bodies when not mating. Please stop sending questions about penises" ...it wasn't her first animal penis question submitted, and I'm assuming she'd developed a reputation.
- rob74 5y agoI was aware of the cloacas, but I didn't know that some birds do have penises, so thanks for that important info! BTW some mammals (notably cats and dogs) also "store" their penises when not mating...
- rudian 5y agoYou might enjoy researching the duck’s reproductive system.
- bluesroo 5y agoThis is definitely in the top 10 funniest things I've read on the internet. The fact that they reluctantly answered the question is incredible.
- ddingus 5y agoYour mum had a solid sense of humor.
- 10729287 5y agoand she really liked penises
- fho 5y agoHN does reddit?
- Stratoscope 5y ago> Please don't post comments saying that HN is turning into Reddit. It's a semi-noob illusion, as old as the hills. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html Of course I don't want to be a dick about this...
- rudian 5y agoHN doesn't do reddit, but your mum
- pengaru 5y agoDo you happen to recall the other questions/responses?
- nostromo 5y agoSeattle Public Library has this. You can even chat with them online. (I'm not linking to it because I'm not sure they want the attention.) My friend works there. She loves interesting questions -- probably even about penises. Unfortunately she says a lot of old folks use it just ease their loneliness and to ask tech support questions.
- ddingus 5y agoThat is both beautiful and sad.
- gorgoiler 5y agohttps://www.bbc.co.uk/programmes/m000tcbk https://www.bbc.co.uk/programmes/m000tcbk From the Goodreads blurb: ”a novel focused on the letters exchanged between Tina, a hardworking farm wife of three children and a museum curator and widower named Anders in Denmark. Their unlikely correspondence begins when Tina's seeks more information about the museum's most famous exhibit.”
- stormdennis 5y agoThat's fascinating. I can remember pre-internet days being resigned to not knowing stuff. For example albums in my country generally didn't include the lyrics. Every time it came on the radio, I asked people what was the singer saying over and over in REM's "The sidewinder sleeps tonight". Nobody knew. Another was a foreign language pop song I remembered from when I was on holiday abroad as a teenager. I searched fruitlessly for it in record shops at home. Decades later, on a whim I found it by googling and then the original video on youtube (I'd only heard it on juke boxes)
- JackFr 5y agoIn college in Washington, DC, in 1987 or so, drinking after hours in a bar (at about 3:30AM) we were having a argument over which was the capital and which was the largest city in Scotland. Not reaching any agreement, the bartender wisely realized that the British Embassy would have a duty officer on, who he called from the bar, and who quite happily answered all of our questions and settled the argument.
- stormdennis 5y agoVery good! That actually reminds me of a similar story from a very well known sportscaster in my country who specialty was, say, rugby. One night he was on duty when a call came in from someone trying to settle a argument about soccer, something like which team had won the most soccer league titles A or B. He replied that he wasn't an expert but he was pretty sure it was team A. Silence on the line, then the voice came back asking Is that Joe Bloggs?, he replied that it was and then the voice said and what the fuck would you know about it? and hung up.
- gumby 5y agoThis is the origin of the Guinness book of records: Guinness sent it to pubs as a fun advertising gimmick. In the days of poor information diffusion I guess content marketing was even more important than today: the Michelin Guide was similar: the tyre company wanted to encourage people to drive more, and figured the guide book would not only help with that but people would have the name Michelin in front of them. Hence the star ranking (go if you’re in town; if you’re in the area, worth diverting your trip a bit; worth making a special trip). I actually used to jokingly call the iPhone “the destroyer of bar bets” but after a year or so on the market those discussions had pretty much died off, so maybe it wasn’t a joke.
- lqet 5y agoI've seen ducks mating. For their body size, they have magnificent penises. Flying with these things flopping around would not only be very difficult without getting caught in something, it would also be extremely irritating to people.
- sneak 5y agohttps://youtu.be/qwjEeI2SmiU https://youtu.be/qwjEeI2SmiU cw: nsfw
- TheGrumpyBrit 5y agoIn the early 00s there were a number of text services providing the same function. I got banned from one for the questions "What is the collective noun for a clitoris?" and "What is the resonant frequency of a clitoris?" I imagine they were a fun place to work at 2am.
- 14 5y agoWho remembers literally having to remember dozens of phone numbers off the top of your head? With no internet to look it up one would either have to have a phone book handy or remember numbers in your head. Which is funny because one of the main numbers I remember learning was the movie theater movie line where you could get info about what movies where playing.
- ddingus 5y agoI wish I had a photo, but yes! I find it hard to recall a contact number today. We get to use names, so that skill drops off quick. Growing up, we had a wall mounted phone with an insane cord. Something like 15 to 20 feet so people could take a call and walk into the adjacent room. One day, I wrote an important number next to the phone on the wall, and it started! Mom asked about it, and said something about writing on the wall being bad. I said something about the difference, because it is easy, right there, won't get lost.. She then put the school, family, few other things next to it. Instant buy in! I remember feeling good about that, like we did something that matters and was unorthodox. I took one last look at it before moving out and into my life: There it was. Our lives on the wall next to the phone. That pizza place, family, services, church, schools, friends, and other bits: birthdays, various identifiers, locations. When I left, that on the wall directory was damn near a square meter! A phone book was right below on a little stand. Actually two: the local one, very small. And the yellow pages. Huge. One day, my brother drank gasoline! I was the only one home and sure enough! The little green poison control sticker was on that wall, next to the phone. Called them and they told me what to do, until someone could respond.
- 7402 5y agoThe Berkeley, California Public Library used to have an "after-hours reference librarian" on duty in the late 1970s or so. You could call up in the evening and ask them a question. I remember once calling and asking how much Vitamin C was in an orange, waiting on hold for a minute or two, and then getting the answer.
- iafisher 5y agoWikipedia offers a similar service: https://en.wikipedia.org/wiki/Wikipedia:Reference_desk https://en.wikipedia.org/wiki/Wikipedia:Reference_desk
- steve_adams_86 5y agoWithout the thread gaps, could the cap potentially be pushed off near the end with a lot of force?
- joeman1000 5y agoI think they mean gaps which run vertically. The thread is ‘interrupted’ and isn’t continuous. Thread spacing is normal, I don’t think they refer to this.
- steve_adams_86 5y agoDefinitely, this is what I envisioned they were describing (right side threads): https://www.capmakingmachine.com/Content/upload/2019330588/201909091637547938851.jpg https://www.capmakingmachine.com/Content/upload/2019330588/2...
- tempestn 5y agoBased on the anecdote from peterburkimsher below, and not seeing any other reason to vent the pressure, I would guess so.
- kfarr 5y agoYes the patent linked below includes this humorous introduction: "In order to prevent "missiling" of the cap of a bottle or other screw-top container intended to contain a carbonaceous beverage, the screw-thread ridge 11 on the neck 13 of ..."
- simooooo 5y agoI’m stealing “carbonaceous beverage”
- animal531 5y agoLook at my other comment, but basically it's a surprising amount of pressure/force. If you're expecting it it shouldn't be a problem, but if not it can catch you unaware. It's a neat little design addition.
- peterburkimsher 5y agoThat's so fascinating! Picture: http://preview.turbosquid.com/Preview/2014/07/11__16_24_14/Plastic_Bottle_Screw_Cap_000.jpgdc1affc5-5ad1-44ae-8cd7-2bd0f9e81428Original.jpg http://preview.turbosquid.com/Preview/2014/07/11__16_24_14/P... More discussion: https://www.reddit.com/r/AskEngineers/comments/372h8x/why_the_screw_of_plastic_bottles_have_small_gaps/ https://www.reddit.com/r/AskEngineers/comments/372h8x/why_th... Last weekend, on my way to the supermarket, I saw a juice bottle blocking a drain. To follow UncleBob's advice to clean as I go, I picked it up. https://www.youtube.com/watch?v=BSaAMQVq01E&t=2021s https://www.youtube.com/watch?v=BSaAMQVq01E&t=2021s I wanted to pour out the remaining orange juice for a nearby tree to get its vitamins. Pop! The cap flew off, lightly knocking off my forehead, but with much force. Thank God it didn't shoot into my eye, it was quite powerful. Although it wasn't a fizzy drink by design, the juice had fermented in the hot sun. Today I learned that there's a solution to the cap flying off, using a different design of screw thread! Thank you jfrunyon for posting this to Hacker News so we can all learn from each other :)
- zimpenfish 5y ago> The cap flew off, lightly knocking off my forehead, but with much force. I have a vague memory from the 80s of a UK consumer show ("Watchdog" or "That's Life") highlighting the dangers of opening pop bottles with your teeth because the caps could fly off and smash your teeth / soft palate etc. Not finding anything from the searches though.
- Symbiote 5y agoI remember some concern about bottle and jar openers without guards meaning the cap on a soda bottle could hit the user on the eye. I think my mum quietly "stole" the one my grandma had, since her grip was becoming a bit weak. https://www.istockphoto.com/photo/bottle-jar-opener-made-from-rubber-on-white-background-gm1053485978-281461430 https://www.istockphoto.com/photo/bottle-jar-opener-made-fro...
- erk__ 5y agoHere is what I believe to be the original patent from 1979 as well https://data.epo.org/publication-server/document?iDocId=10310&iFormat=2 https://data.epo.org/publication-server/document?iDocId=1031...
- ashtonkem 5y agoSince the article mentions it, the amount of carbonation in any given beverage actually varies by a lot. The traditional measurement of carbonation is in "volumes", which is the amount of space the CO2 would take up at standard temperature and pressure (32F and 1 atm). Coca Cola is usually packaged at 3 volumes; if you took all the CO2 out of the soda it would occupy 3x the volume of the soda it came from. Alcoholic beverages on the other hand have a pretty wide range of regular carbonation levels. On your lower end you have stouts and Scottish ales at 1.9-2.1, and on the high end you get your dubbel and heffe weisen at 3-3.5 volumes. Champagne is regularly in the 4.5-6 range, which necessitates a different bottle and closure design to handle the 2-3x pressure it contains compared to beer. On a particularly dumb note, ciders are limited by law to 0.64g per 100ml, or 3.2 volumes. Above that level they cease being ciders and instead become a sparkling wine. This is very important because natural cider is taxed at $0.226 per gallon, while sparkling wine is taxed at $3.30 or $3.40 per gallon depending on how the carbonation is added. This is a difference of roughly 30 cents per standard bottle, or $1.79 per six pack; enough of a difference to make similar products more attractive on the market place shelf. https://www.ttb.gov/tax-audit/quick-reference-guide-to-wine-excise-tax https://www.ttb.gov/tax-audit/quick-reference-guide-to-wine-...
- divbzero 5y agoWhoa, the numerical carbonation levels actually correspond pretty well to my memory of how “fizzy” those drinks taste on the tongue. This is the coolest trivia I’ve learned in awhile.
- KennyBlanken 5y agoYou know what's even dumber? Having a product that can vary in price 1000x or more...and taxing it by volume, instead of by its price. Yet another way the rich shift more tax burden away from themselves. They pay a pittance of a tax on a $5,000 bottle of wine, while everyone buying "two buck chuck" at Trader Joes ($3-4/bottle) is getting hit with a huge tax percentage-wise. Even taxing alcohol at different rates just because it's made with specific fruits is idiotic. It smacks of lobbyists buying off their congressional reps to get a rival sub-industry slapped with a higher tax. Just tax alcohol by its value, across the board at the same rate.
- poglet 5y agoSo what happens if there are no gaps, does the lid go flying off?
- mixmastamyk 5y agoApparently yes, read peter's comment: https://news.ycombinator.com/item?id=28914869 https://news.ycombinator.com/item?id=28914869
- totetsu 5y agoTry putting some carbonated drink into a thermo flask with a sealed lid and open it after it's been in your bag.. the seal holds right to the end and the POP. I have a hole in my kitchen ceiling from accidentally storing dry ice overnight in one too.
- mulle_nat 5y agoIf I look at my bottle caps here in Germany, my 0.7l "soda" water bottles, don't have gaps. The Coca Cola glass 0.5l bottles don't have gaps either. Club Mate 0.5l doesn't have gaps. Only the Sprite bottle 1l has gaps. Handlingwise I don't notice any difference. Maybe because it's a learned technique thing, you twist it, let gas evaporate then open it. I don't even think about it.
- pantalaimon 5y agoI think this only works with PET bottles (the thin, elastic ones) as they work a bit like a balloon and can store more pressure energy.
- pantalaimon 5y agoYes! It takes some practice but as a kid i managed to launch the lids off water and soda bottles that had previously been opened (more gas volume) and carried in a bag. You need to edge the cap close to the point before the gas can escape, then give it a flick so it can twist open the last bit by inertia. Apply some pressure to the plastic bottle while doing so. When it works the cap would fly off with a loud bang and the rapid change in pressure causes condensation inside the bottle, allowing you to push out clouds of vapor. I think they changed the design of the bottle at some point and this would no longer work.
- twofornone 5y agoThis webpage is a relic from an internet that no longer exists. This style of forum, kind of nostalgic. I can't help but feel that we lost something great with the modern web.
- trhway 5y agoBack in 199x plastic bottles with soda would sometimes explode inside the bag when we'd be walking on a hot day - it were earlier years of making soda in large plastic bottles in Russia and it was all "bottom line optimized" like visibly cheap low quality plastic, etc. And about 20 years ago a woman in Russia got her eye injured by the metal cap that flew off a soda bottle she tried to open. She sued the manufacturer ("Bravo" - once opened their metal cap had the lower band still attached and broken with couple sharp edges sticking out) - don't know the full results, yet the manufacturer started since then to use plastic caps instead of metal.
- dingaling 5y agoBack in the 1990s the UK TV programme "Watchdog" ran a report about projected bottle caps injuring people during opening. It was named "missiling". Since then I've always ensured that the cap is facing away from anyone when opening a pressurised bottle. Funny how one short report can cause a lifelong change in behaviour.
- regularfry 5y agoPutting gaps in is also a useful trick to have up your sleeve if you're 3d printing internal threads. If you print threads as continuous bodies, the filament on each layer is effectively a ring which is (because of thread geometry) less supported for part of its length. When it contracts slightly as it cools, it can pull the overhang section of the thread away from the body of the object, and you end up with loose filament strung across the gap. If you cut gaps along the thread, when it prints you're effectively building a lot of small separated ledges out from a side wall. You don't have that cooling/tensioning effect and there's nothing to pull the filament away from where it's laid down so you end up with a cleaner thread. That's as long as your retraction settings are well tuned, mind - continuous thread is one long extrusion with no retractions, whereas thread with gaps is potentially lots of islands, depending on how your slicer reacts to the geometry.
- bsdubernerd 5y agoI assume this happens on very small threads and/or with thick layers? I print both depending on size, and a full thread is usually more self-supported, not _less_, while printing faster to booth. Toothed threads tend to suffer from curling more easily when comparing at the same overhang slope, and are weaker structurally. I'm using toothed threads for larger threads to save on time/material usually, or oddball constraints. I can see why you would get the effect you're describing, but this would only happen if you're printing with insufficient Z resolution in order to support the overhang of the thread. I cannot see how a toothed thread would improve in such a scenario.
- regularfry 5y agoYes, small threads in particular are prone to this. Although the first thread I needed it on was 2mm pitch with 0.2mm layer height, so not that small.
- bsdubernerd 5y agoI'm a bit surprised by this. 2mm pitches are well printable at .2, although I usually don't use the stand ANSI/DIN profiles, but limit the overhang profiles manually depending on the material (from 45 up to 70, really) to improve them. Still, at 2mm, this shouldn't be necessary. Maybe the slicer you're using is doing something odd. Keep in mind that if the filament string looks pulled in a full thread, a toothed thread with the same settings will be even weaker. In such cases it will change the result to localized sagging areas, where the structural element is just the start/end of each tooth. A screw, even plastic one, will easily self-thread into the thin amount of plastic remaining, but that doesn't mean that the thread works as intended structurally. If you have issues with smaller threads my reccomendation is to print an undersized cylinder and use a tap for best results, or just slightly undersize the hole and self-thread instead.
- dotancohen 5y ago> Non-pressurized packages (like bottled water) normally contain > smooth, non-vented threads since there is no internal > pressure to be relieved from the inside of the package. Actually, some bottled water bottles do have the vents. Maybe to reduce the quantity of plastic in the bottle by another 1% without sacrificing rigidity in more critical areas? In some industries a 1% optimization of part of a process could be non-trivial, especially in a bottleneck component or material.
- Symbiote 5y agoThe greater saving is probably in using the same bottles / caps for still and sparkling water.
- nallerooth 5y agoI didn't know I wanted to know about this until I saw the link. Well done! :D
- wombatmobile 5y agoI noticed those gaps in the thread of a thermos (vacuum flask) last week. Presumably it’s to vent inward airflow when cooled liquid creates a vacuum.
- neur4lnet 5y agoAlso, many thermos flasks have a feature whereby you can pour out the contents without unscrewing the lid all the way, so there will be a large channel interrupting the threads to allow liquid out, and one or more opposing interruptions to let air in.
- animal531 5y agoI figured this out once myself. I had dropped my Coke plastic cap, so to replace it I took a metal cap from a non-carbonated drink (maybe water) that was of the same size. When I eventually opened the bottle it basically shot my hand off with some speed and shock. I was quite surprised and then investigated and found the gaps, it's a neat little addition to the design (and makes one wonder how many other little details like this there are in daily life products that we'll never even know about).
- neur4lnet 5y ago>>> (and makes one wonder how many other little details like this there are in daily life products that we'll never even know about). That's what I find most interesting about things like that. They are everywhere and its a joy to find them.
- rightbyte 5y ago> makes one wonder how many other little details like this there are in daily life products that we'll never even know about You notice the hard way when you try to build things yourself. All the small things that make mechanics go together ... like just getting the jiggle just right to make things not seize or be too loose. The amount of institutional knowledge around is insane, and I fear that the quality drop in things in recent years is just not due to cheap imports, but also that employee employer loyalty is punished by the employers nowadays and they are losing experienced engineers. Like the "I'll be designing cupboard hatches here till I retire"-generation is retiring and the new engineers are job-hoping?
- deleted 5y ago[deleted]
- jihadjihad 5y agoIn a similar vein, I found this explanation [0] of how and why a soda can's tab functions the way it does to be fascinating. Very clever and elegant solution to the problem of opening a can under pressure. 0: https://www.youtube.com/watch?v=hUhisi2FBuw https://www.youtube.com/watch?v=hUhisi2FBuw
- albrewer 5y agoEngineerguy's youtube channel is a real gem, and I wish he made more videos. Every topic he's picked has made the subject matter interesting, even about the really mundane things like baby diaper design. My substitute channels in the meantime have been Practical Engineering and Applied Science, but those two don't really have the level of depth or polish (respectively) as Engineerguy.
- scrollaway 5y agoPractical engineering is up there. I will check out Applied Science. In a similar vein I recommend Not Just Bikes and City Beautiful for city planning details you haven’t thought of. It’s less expert advice and more observations, at least for NJB, but it’s eye opening! And of course, Technology Connections.
- albrewer 5y agoApplied Science is just a really smart guy who works (worked?) at Valve who reads cutting edge research papers and tries to recreate it in his home machine shop / garage. I just discovered Not Just Bikes a few weeks ago, and I'm really digging his content. He complains and rants too much for me to really binge his channel, but I still go back to it for small doses. I'll work my way through his catalogue eventually! I do like Technology Connections, but I'm a mechanical engineer by training so a lot of his videos don't really cover new stuff for me, or it's a 22 minute video for 8 minutes of real content. He tends to go over each concept repeatedly from sliiightly different perspectives each time. Which is cool, but I end up skipping around in the video until he gets to the point.
- mhb 5y agoHalf the time when I try to open the twist tie on a loaf of bread, it tightens. I called Arnold Bread to find out why the ties didn't consistently loosen counterclockwise. The explanation wasn't entirely satisfying, but the breads come off the production line and go to different twist-tie-applying machines which twist in different directions.
- buescher 5y agoThis sounds like a 1990s Microsoftean interview question. Next up, manhole covers...
- throwaway0a5e 5y agoNow I wonder why they chose to use cuts rather than a slightly different thread form with a larger leak path.