[HN Gopher] How to grow sodium chloride crystals at home ___________________________________________________________________ How to grow sodium chloride crystals at home Author : kdavis Score : 537 points Date : 2021-11-17 16:54 UTC (6 hours ago) (HTM) web link (crystalverse.com) (TXT) w3m dump (crystalverse.com) | djrogers wrote: | These are beautiful. Seems that a possible solution to the | problem outlined at the end of the post (they are not quite | cubical, but flat) would be to gently flip them a few times | during the months they are growing. | mh-cx wrote: | I've never seen this before and wonder how stable/fragile are | those crystals? Are they very touch-sensitive or can you carry | them around easily in your pocket? | nojs wrote: | I've done this as a kid and they're not really fragile. You | could definitely carry it in your pocket. | dylan604 wrote: | "If it looks like picture 4 or 5, let it grow anyway. " | | Anyone got a location on picture 5? | Kikawala wrote: | It should say "If it looks like picture 3 or 4, let it grow | anyway." | ulzeraj wrote: | I'm ashamed to confess that licking those pretty cubes was the | first thing that passed through my mind. | at_a_remove wrote: | I have often wondered what sorts of crystals that you can grow at | home that are relatively hard, sturdy, long-lasting. | jackallis wrote: | looks like a fun a project to work with kids | anorphirith wrote: | is that even legal ? | ffhhj wrote: | Is it possible to grow crystals in moulds to give them custom | shapes? | Borrible wrote: | https://en.m.wikipedia.org/wiki/Chemical_garden | fcatalan wrote: | My daughter has this as an school assignment, with some | implication that it is some sort of a contest, and we managed to | grow quite a few of similar quality to the seed crystals on the | site in 4 days, which was the original (poorly thought IMO) | deadline. The trouble is that no one else was able or cared to do | it so fast, so the deadline has been slipping for a couple weeks | now, with our best crystals going to school and back a few times, | getting scratches and broken bits instead of nicely growing | undisturbed. A bit discouraging. I'm now remembering how | frustrating was for me to take school related things too | seriously and discover you cared more than your teachers when I | was her age. | 5faulker wrote: | Could be a good self-sufficiency project too. | dekhn wrote: | We managed? When I was a kid I never got help from my parents | on these projects, and hated the kids who "won" because their | parent helped. | | On the other hand, being the competitive person who excels in | science projects is often a very good predictor for being able | to handle the tedium of a scientific lab job. | JKCalhoun wrote: | I was enamored with "Things of Science" when I was a kid. So | much so I began collecting them off eBay, scanning the little | science booklet and sharing them for posterity. | | As such I love DIY science like this. | | Regarding crystals, I have scanned in and cleaned up two | projects relating to crystals: | | http://underlandia.com/index.php/2017/09/24/things-of- | scienc... | | http://underlandia.com/index.php/2020/08/21/things-of- | scienc... | zt9 wrote: | @JKCalhoun just got this account to say thank you for this | - I am home schooling with my kids this year and this is a | gem of a find. | germinalphrase wrote: | Thank you for sharing Things of Science! | detritus wrote: | My daughter's only 2 and a bit right now, but I can totally | envision an environment wherein I'm acting as an idiot sub- | lab assistant role, helping with the basics of her demands. | | Of course, I'd not want to do her work for her, but more than | equally, I'd be quite happy to have a '5% We-encouraging' in | her vocabulary when it comes to her explaining herself. What | parent wouldn't, if they can? | dctoedt wrote: | The sitcom _Modern Family_ had an episode in which kids had | to do an egg-drop project and were helped by their respective | parents. | | https://www.wikiwand.com/en/Egg_Drop | fcatalan wrote: | When I was a kid I never got help from my parents either and | I now think that I would have benefited from a bit of closer | attention. I developed a huge spectrum of bad practices and | behaviours that I'm inclined to think I could have avoided at | least in part. I want to think there's some space between | doing their homework for them and not caring about the | minutiae of their education, and I want to be there. | koolba wrote: | > I want to think there's some space between doing their | homework for them and not caring about the minutiae of | their education, and I want to be there. | | Even showing a lack of interest in their pointless projects | is a life lesson in priorities and individualism. | fcatalan wrote: | But the project isn't pointless! | | For example, most of my help was to make sure she took 10 | different containers and placed them in different | locations around the house to increase the probability of | getting a few decent crystals. I discussed redundance | with her in the context of explaining why some of her | friends were not getting results from their single try. I | think that these practical thought patterns are extremely | valuable, better than creating a miniature jaded adult... | cornell532 wrote: | You sound like a great parent doing right by your | daughter. She's lucky to have you. | | The point of school is to learn to think + learn to face | adversity & failure.... | wilkommen wrote: | You're doing good. Just cause someone else's childhood | sucked and they feel like they learned something from it | doesn't mean it's a good thing. You learn a lot more | about how to live well from being loved than you learn | from being ignored and neglected. | bawolff wrote: | > Even showing a lack of interest in their pointless | projects is a life lesson in priorities and | individualism. | | If you teach your kid the lesson that life sucks and | trying is for suckers, don't be surprised when they | believe it and don't get anywhere in life because they | never try. | spaetzleesser wrote: | "When I was a kid I never got help from my parents on these | projects, and hated the kids who "won" because their parent | helped." | | I wish my parents had shown interest in stuff like this and | supported me to some degree. It's not about doing the whole | project for the kids but showing interest is super helpful. I | often gave up on stuff because my dad would basically say | "what's this nonsense for?" | | I noticed this when read books about Steve Wozniak and | Richard Feynman. Their dads showed interest and encouraged | them to explore the world and also challenged them from time | to time. | csa wrote: | > When I was a kid I never got help from my parents on these | projects, and hated the kids who "won" because their parent | helped. | | These can be two different things: | | 1. Constructive help from parents has (at least) two | components. First, it shows your child you care. This may | seems small, but it's not. Second, and I think this is what a | lot of HNers would appreciate, is to help your child to | develop good processes. There is a lot that goes into this, | and it can be parent-centered or child-centered, but having | your child reflect on process and (ideally) implement some | good processes can really set them up for later in life. | Imho, parents should have to write a short narrative about | what involvement they had in their child's project, if any. | This is required at some of the local schools where I live. | | 2. Having the parents do the project for the child is just | silly. Most decent teachers can see through this (assuming | they care). Congrats to the adult parent for winning | elementary school or middle school as an adult. :-/ | sokoloff wrote: | > Most decent teachers can see through this (assuming they | care). | | I entered the science fair as a kindergartner with a poster | project explaining how (the output color-mixing of a) color | TV worked. | | Principal accused my parents of doing it; they had no idea | what he was talking about and protested that I'd done it. | So he interviewed me about it and left convinced I'd done | it. ;) | Waterluvian wrote: | I know exactly how you feel. Very frustrating and sometimes | disenchanting to discover they don't really care. | | But perhaps also a good life lesson because that happens all | the time. It's good to try and develop a healthy self-driven | passion. Oh, you don't care? That's fine because I do and I | learned a lot. | seanalltogether wrote: | More discussion from original poster. | https://www.reddit.com/r/mildlyinteresting/comments/qvxyjg/a... | philipkglass wrote: | Calcium tartrate is a great high speed introduction to crystal | growing because it is very forgiving and "magical." You can get | ~millimeter size crystals in seconds. Then once you're hooked you | can try growing crystals that require more patience/technique. If | you ever saw the demonstration of lead (II) iodide precipitating | from solution [1], this demonstration looks similar except that | the crystals are sparkly and colorless instead of sparkly and | golden. | | You'll need potassium hydrogen tartrate (cream of tartar), sodium | hydrogen carbonate (baking soda), and calcium chloride (sold as | DampRid or Pickle Crisp). | | Add a spoon full of baking soda and a spoon full of cream of | tartar to a glass of distilled water. They should fizz together | as the baking soda neutralizes the acidity of the cream of | tartar, releasing CO2. This is what you want, since the mixed | neutral salt of tartaric acid is more soluble in water. Stir and | wait for the fizzing to die down, then gradually stir in small | portions of more cream of tartar until the additions stop | dissolving. Let the solids settle in the glass. | | Meanwhile, dissolve a spoon full of calcium chloride in a second | glass of water. It should dissolve readily with a bit of | stirring. | | Once residual solids have settled in glass one, decant the clear | liquid into another glass. | | Now pour the clear decanted liquid into the calcium chloride | solution with stirring. Within seconds, you should see sparkling | needles rain out of the solution. These are your crystals. The | transition is especially striking in direct sunlight. The | crystals can be saved and seem to remain stable in air regardless | of ambient humidity. | | I unfortunately have not seen this demonstration written down | elsewhere so I can't offer a citation. I came to it by personal | experience when I was on a crystal growing kick as a kid. (Though | it may well have been written down somewhere that I have never | come across.) | | [1] Like in this video: | https://www.youtube.com/watch?v=AO67MnZaAvQ | BuildTheRobots wrote: | Do you know how safe the resulting crystals are to handle? | philipkglass wrote: | I believe that they are safe to handle. None of the compounds | or elements involved are toxic at moderate doses even if | ingested. I personally handled these crystals with bare hands | many times. | huhtenberg wrote: | Potassium bitartrate is also a great introduction to crystals. | | Get a bottle of good red wine, 2010 or thereabouts. Uncork and | drink it. Now look at the bottom of the last glass, if you | still can, and - voila - potassium bitartrate. | | If you don't find any, don't despair and try another bottle. | drran wrote: | Search for <<Rochelle salt piezoelectric crystals>>. | invalidusernam3 wrote: | Assuming these are edible when complete? I could imagine these | for fancy dinner parties where each diner gets a crystal and a | small cheese grater | stingrae wrote: | I don't think a cheese grater would work? A hammer would be the | tool I would go for. | darkwizard42 wrote: | Seems like it is edible given the only ingredients to start | were salt and water. I don't know about the durability though. | Do these break easily or are they very dense? | | Guess we gotta grow some! | jrockway wrote: | Welp, this is a silly project that I have no choice but to try. | Looks straightforward and rewarding with a nifty end result. | | This is a content-less comment but... great article, thank you | for submitting. | legohead wrote: | There's also "salt pyramids" [1] which are desired in Culinary | field for their look and texture. Be pretty cool if there was a | way to grow a transparent salt-pyramid. | | [1] https://www.youtube.com/watch?v=FVEZuzEHwQk | jedimastert wrote: | I'm glad you linked to the Adam Ragusea video, you saved me the | trouble of finding it. | | I really like Adam's videos, he does a ton of research, and has | a very descriptivist approach to cooking in general | hansjorg wrote: | There's a section about pyramids in the article: | https://crystalverse.com/sodium-chloride-crystals/#saltpyram... | thunderbong wrote: | What a fantastic article! I didn't know it was possible to grow | crystals like that from salt. Have to try this! | alhirzel wrote: | NaCl is a lensing material in the LWIR bands, this could lead to | very cool applications for cheap thermal cameras | teeray wrote: | I'm intrigued, but no nothing about lensing materials or the | LWIR band. Care to expand or link to a good resource for | learning more? | alhirzel wrote: | FLIR has a good handbook on some of the physics: https://www. | flirmedia.com/MMC/THG/Brochures/T559243/T559243_... | | The rest is light transport, e.g. lensing via index of | refraction: https://courses.lumenlearning.com/boundless- | physics/chapter/... | | Here's a cool article on a piece of an old spectrometer: | https://utsic.utoronto.ca/spectroscopy-beyond-the-visible- | sp... | | More information from a distributor of optics: | https://www.knightoptical.com/stock/default/windows-and- | diff... | rbobby wrote: | > it will probably double in size in a week and reach 1x1 cm in a | month | | TIL it takes a long time to grow a perfect salt crystal of any | size. | avian wrote: | > Indeed, table salt is often used in kids' experiments to | demonstrate crystallization. It's a simple activity, but the | results are disappointing. | | I remember this was one of the things I tried countless times as | a kid. It never worked - the books showed these nice, clear | crystals but all I ever got was a crust of dried salt and maybe | one tiny crystal a few mm across. | | I'm sure most of those "science for kids" book authors never | tried a single one of their experiments. | jareklupinski wrote: | i tried a similar 'experiment' once with sugar to make rock | candy, failed the first attempt | | my grandma saw and told me to use the rest of the string and | sugar I had, enough for 12 more tries, and do them at once but | in different areas of the house | | only two actually grew but i learned the value of spreading | risk and unknown unknowns ( much later, on reflection :) ) | dylan604 wrote: | Did this as a kid as well. When I got to high school | chemistry, we did an experiment on super saturation of the | sugar. Much better results, much faster! | sumtechguy wrote: | hehe I did that super saturation thing as a kid. one of the | instructions was pour until saturation happens. It didnt. I | ended up with 5 pounds of rock candy. | dylan604 wrote: | Did you do the version where you let the super saturated | solution cool down slowly, and then drop a single grain | of sugar into it? | dekhn wrote: | When I wanted crystals for microscopy, I made a mother | liquor by pouring an enormous amount of sugar in a tiny | amount of water (beyond saturation) and then just let the | solvent evaporate in a heated chamber. | | Made big rocks. https://en.wikipedia.org/wiki/Mother_liquor | dylan604 wrote: | Never heard that term before. Not sure I understand the | point though. After you supersaturate and then form | crystals, the mother liquor is just the left over content | that didn't make it into the crystals. What is the | purpose of using those remnants? | dekhn wrote: | mainly to get more crystals and as a growth medium for | existing crystals. | spike021 wrote: | We did a rock candy experiment in 6th grade and probably | attempted it a few separate times, specifically because we | kept having issues. I think at least one batch got moldy. | But, if I'm remembering correctly (this is over a decade | ago), we may have been placing the dishes near where sunlight | hit, so that could've been part of it. | carlos_rpn wrote: | Could it be the requirement for "Uniodized table salt"? I don't | think I'd be able to find it around here, and I can't think of | any good reason someone would have it on hand either. | smeyer wrote: | Have you actually checked your grocery store? Mine sells both | iodized and uniodized table salt, in addition to the kosher | salt idea that folks have mentioned. I know the OP said that | they worried about anti-caking agents in kosher salt and I'm | no expert, but I thought they didn't usually have them. | JoeDaDude wrote: | 'twould appear that non-iodized salt is used in cheese | making, so maybe salt labeled as cheese making salt might | work. | robocat wrote: | Perhaps get a 20kg / 40lb bag of pool salt for $20. | | I'm not sure about purity or anti-caking, although some | brands are advertised as high purity. You can even get it | delivered in the US: https://www.amazon.com/s?k=pool+salt | | Perhaps look at the 20kg bags of food salt sold at | wholesalers, which might not be iodised. I recall seeing one | at a Chinese store, but I'm in New Zealand, so I'm unsure | about the US. | btilly wrote: | The article says that iodized table salt doesn't work, and | isn't optimistic about kosher salt either. | nitrogen wrote: | If you can get "kosher salt," IIRC that should be non- | iodized. | derobert wrote: | If you look for canning / pickling salt, that should be free | of both iodine and anti-caking agents. | outworlder wrote: | What about dishwasher salt? It's usually 100% sodium | chloride. | jldugger wrote: | I dont think anyone in the US sells that tho. | unwind wrote: | What? Why not? | | A quick check of Amazon.com [1] turned up a bunch of US- | looking products, at least. | | [1]: https://www.amazon.com/s?k=dishwasher+salt&crid=X602 | 5PAVFBMS... | jldugger wrote: | The only brand I even recognize is Finish, and they're a | UK firm, not American. Technology Connections mentions[1] | it's a European thing: "I have never ever encountered | one, and I don't think I've ever seen dishwasher salt | sold in a store." | | [1]: https://www.youtube.com/watch?v=Ll6-eGDpimU&t=2098s | outworlder wrote: | > The only brand I even recognize is Finish, and they're | a UK firm, not American | | Plenty of non-american firms sell products in the US. | Like... I don't know, Nestle? | | I watched the same Technology Connections video. He does | mention Bosch dishwashers by name. Those are available in | the US. It's just that people barely bother understanding | how dishwashers work, let alone _very infrequently_ | refilling the salt. Heck, people drive without checking | tire pressures, dishwasher salt has no hope. | | Not surprising that most stores don't bother. It lasts | forever too. | jsmith45 wrote: | Dishwasher salt is not actually widely available in the US, | since we we generally don't have dishwashers with built in | water softeners that need the salt. | | Most places either have soft water from their water supply, | or people install a whole house water softener, if their | water is hard enough to cause problems with mineralizing on | dishes. | | The salt for the whole house water softener would probably | work, but the bags are pretty huge. | outworlder wrote: | > Dishwasher salt is not actually widely available in the | US | | I am in the Bay Area. I bought some off Amazon no | problem. It came from the US too. | | > since we we generally don't have dishwashers with built | in water softeners that need the salt. | | Landlord installed a Bosch dishwasher, which has a water | softener. The water is pretty hard (I can see by the | shower faucet, and confirmed on the utility website). I'm | assuming he didn't bother to import the dishwasher from | Europe so it must be available in the US. | nitrogen wrote: | _I 'm sure most of those "science for kids" book authors never | tried a single one of their experiments. _ | | They should at least recommend distilled water because tap | water impurities vary greatly from place to place. | leoc wrote: | Parents! Are your teens getting into "salt"? Know the signs. | ttoinou wrote: | Looks really good. My three chemicals for crystal growing are | | ADP | | https://en.wikipedia.org/wiki/Ammonium_dihydrogen_phosphate | | and MKP | | https://en.wikipedia.org/wiki/Monopotassium_phosphate | | and Alum | | https://en.wikipedia.org/wiki/Potassium_alum | | but probably table salt is cheaper.. | mellavora wrote: | Careful using Xerox scans to create your posts... | isoprophlex wrote: | Those monopotassium phosphate crystals look gorgeous! Any tips | for places to buy that salt? | ttoinou wrote: | 6 years ago on eBay 2 kg for 30 USD from UK to continental | Europe. 2 months ago on Amazon 5 Kg for 43 USD delivered in | Europe. It's a fertilizer so it's not supposed to be | expensive | k__ wrote: | At school we had a sodium crystal that was around 15cm in | diameter. | | A teacher said, they found it in the woods. | isoprophlex wrote: | When I was an organic chemist, growing crystals was of paramount | importance for certain structure determinations using X-ray | crystallography (to answer "did I really prepare what I think I | prepared?") | | With sensitive compounds, sometimes you can't just let things | evaporate. Also as the article states, weather conditions might | mess you up. IMO the coolest trick we had to solve this was | osmosis of an anti-solvent into a saturated solution. | | A small sealed container with a saturated solution of your | compound/salt is punctured, and put in a bigger sealed container | containing a worse but miscible solvent for the compound under | study. Slow diffusion into the inner container causes very | reproducible crystal growth, as long as you can control the | temperature. | gwerbret wrote: | > growing crystals was of paramount importance for certain | structure determinations using X-ray crystallography (to answer | "did I really prepare what I think I prepared?") | | Ahh, X-ray crystallography, a.k.a. the field of modern | (bio)chemistry that most closely resembles medieval alchemy. | | The excellent 2009 documentary "Naturally Obsessed" [0] is | about how difficult, time-consuming, and frankly irrational it | can be to successfully crystallize certain proteins and protein | complexes. The film is about how some PhD students spend the | entire five-ish years of their degree programs trying (and | mostly failing) to find the secret recipes (protein | purity/additive ingredients/temperature/humidity/phase of the | moon) that will allow their proteins to crystallize, and thus | granting them data with which to populate their dissertations. | | Why irrational? In one case, the secret ingredient is pickle | juice. | | [0]: https://www.thirteen.org/naturally-obsessed/ | voldacar wrote: | That's really clever. How long did this process usually take, | what size crystals were you going for? And were these crystals | ever visually interesting, or do most organic compounds just | form colorless little prisms or cubes? | isoprophlex wrote: | "Sadly" (not for me back then) a crystal 1 mm on a side is | more than plenty for structural elucidation. They were only | ever pretty to me because | | A) you sometimes spend weeks working on the materials that go | into the solution, seeing them feels like a "my god finally" | kinda thing | | B) under a microscope crystals are especially beautiful, even | small crystals. We had a microscope set up in an inert | atmosphere for sensitive compounds, see eg. | | https://www.jacomex.com/wp- | content/uploads/2019/08/microscop... | | About timing: this could take anywhere from days to months... | really dependent on how fast you can go without making ugly | intergrown xtals, on how well you select solvents, etc. | Experimental science can be cruel. | andrewla wrote: | Neat -- turns out that for sodium chloride there is extensive | literature on this. Ethanol is apparently effective as an anti- | solvent, but various dimethylisopropylamine compounds appear to | be more effective and are used in industrial settings. | | Interested now to try this experiment but with ethanol to | better control the crystal formation. | isoprophlex wrote: | Wonderful! I was tempted to do some searching on ethanol, | acetone, any volatile things that are generally available... | good to know ethanol is effective. | | Will be a fun xmas experiment to do! | dekhn wrote: | Crystallography, the study of crystals and the structures of | their constituents, is fascinating. I work in a field where | making crystals like this is so tough that people spend millions | of dollars on robots and reagents that just sit around trying | every possible combination of temperature, concentration, and | other parameters, just to make crystals with high enough quality | to do structure determination. | | Some crystals just never form. I know folks who spent 7 years | trying to get their protein to crystallize and left grad school | with a masters degree instead of a PhD because they failed, no | fault of their own. | Turing_Machine wrote: | I used to enjoy growing crystals when I was a kid. It's a good | indoor activity for the winter. | | Plain white sugar is also interesting. Alum (used to make | pickles, can often be found in the herb and spice aisle at the | store) makes neat crystals. | | If your kids are old enough to be trusted not to eat the | experiments, copper sulfate (used to kill roots that are growing | into sewer lines) makes beautiful crystals. It can be found at | Home Depot-type stores. | | Edit: I see this author has a link to another article on growing | copper sulfate crystals down at the bottom of this article. | Recommended! | jrumbut wrote: | I was trying very hard to remember what the other two "classic | fun-for-kids crystal growing" chemicals were and it was eating | me alive. | | Thank you for the answer, I still remember my alum crystals for | the grade school science fair. | Jiro wrote: | I tried Epsom salts as a kid, since there was some around the | house. They were a lot easier to grow than table salt. | Turing_Machine wrote: | Epsom salts! Yes! Another good one. | mountain_peak wrote: | Alum crystals in a disposable pie pan on a hot water radiator | turned out brilliantly in my youth. | | Fast-forward many years, and my daughter wasn't having much | luck with salt, sugar, or even copper sulfate (that one | looked like a melted smurf). | | I remembered my alum crystals, which she tried, and lo and | behold...nothing! Desperate (on the night before the | assignment was due), I remembered someone mentioning that you | can make crystals with mothball flakes. We picked a bag of | flakes up and heated them up in a dish, and were able to make | long, beautiful crystals on the bottom of a cold glass over | the heated solution. | | The only problem was that as soon as we moved the glass away | from the solution, the crystals evaporated, so she took a | picture of the crystals as they were forming and received | full marks. A happy ending, but the house smelled of | mothballs for a few days! | outworlder wrote: | > If your kids are old enough to be trusted not to eat the | experiments, copper sulfate (used to kill roots that are | growing into sewer lines) makes beautiful crystals. It can be | found at Home Depot-type stores. | | I had a chemistry set as a kid, it had copper sulfate. The only | crystals I've managed to grow :) ___________________________________________________________________ (page generated 2021-11-17 23:00 UTC)