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How to grow sodium chloride crystals at home
- 40four 5y agoThis is a really cool write up and really intrigues me, on the topic of crystals. I admittedly have very little knowledge or frame of reference on the topic. But there is something very cool about the idea that you can ‘grow’ crystals, like they are little house plants, or that they are like little living creatures or something.
- amarant 5y agoThis makes me curious, and I googled a bit trying to find how large you can grow these transparent, cubical crystals. Largest I was able to find was about 2cm to a side, maybe a bit less.. Is there any fundamental reason they don't get bigger than this/lose transparency and form as they grow larger, or is it more that no-one bothered doing growing them larger than that?
- mh-cx 5y agoI'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 5y agoI’ve done this as a kid and they’re not really fragile. You could definitely carry it in your pocket.
- djrogers 5y agoThese 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.
- jackallis 5y agolooks like a fun a project to work with kids
- rbobby 5y ago> it will probably double in size in a week and reach 1×1 cm in a month TIL it takes a long time to grow a perfect salt crystal of any size.
- alhirzel 5y agoNaCl is a lensing material in the LWIR bands, this could lead to very cool applications for cheap thermal cameras
- teeray 5y agoI’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 5y agoFLIR has a good handbook on some of the physics: https://www.flirmedia.com/MMC/THG/Brochures/T559243/T559243_EN.pdf 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/lenses/ 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-spectrum-the-sodium-chloride-prism/ https://utsic.utoronto.ca/spectroscopy-beyond-the-visible-sp... More information from a distributor of optics: https://www.knightoptical.com/stock/default/windows-and-diffusers/ir-windows/sodium-chloride-windows.html https://www.knightoptical.com/stock/default/windows-and-diff...
- f3rnando 5y agohttps://engineering.princeton.edu/news/2021/11/29/researchers-shrink-camera-size-salt-grain https://engineering.princeton.edu/news/2021/11/29/researcher...
- thunderbong 5y agoWhat a fantastic article! I didn't know it was possible to grow crystals like that from salt. Have to try this!
- avian 5y ago> 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 5y agoi 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 5y agoDid 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!
- dekhn 5y agoWhen 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 https://en.wikipedia.org/wiki/Mother_liquor
- dylan604 5y agoNever 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?
- fcatalan 5y agoMy 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.
- samstave 5y ago>>A bit discouraging. I'm now remembering how frustrating was I am picturing you over a mortar and pestle crushing the salt of your enemies whilst a single tear falls into the mix - and en-vigorating (filling with life) - the salt of your defeated enemies..
- dekhn 5y agoWe 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.
- fcatalan 5y agoWhen 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 5y ago> 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.
- seanalltogether 5y agoMore discussion from original poster. https://www.reddit.com/r/mildlyinteresting/comments/qvxyjg/a_salt_crystal_i_grew_at_home/ https://www.reddit.com/r/mildlyinteresting/comments/qvxyjg/a...
- Turing_Machine 5y agoI 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 5y agoI 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 5y agoI 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 5y agoEpsom salts! Yes! Another good one.
- mountain_peak 5y agoAlum 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!
- dylan604 5y ago"If it looks like picture 4 or 5, let it grow anyway. " Anyone got a location on picture 5?
- Kikawala 5y agoIt should say "If it looks like picture 3 or 4, let it grow anyway."
- legohead 5y agoThere'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 https://www.youtube.com/watch?v=FVEZuzEHwQk
- hansjorg 5y agoThere's a section about pyramids in the article: https://crystalverse.com/sodium-chloride-crystals/#saltpyramids https://crystalverse.com/sodium-chloride-crystals/#saltpyram...
- jannyfer 5y agoThat's indeed a pyramid, but the video in the OP is referring to "hopper crystals" which are hollow and hence have different culinary uses vs. regular salt.
- jedimastert 5y agoI'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
- isoprophlex 5y agoWhen 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.
- andrewla 5y agoNeat -- 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 5y agoWonderful! 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!
- voldacar 5y agoThat'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 5y ago"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/microscope-glove-box-2.jpg 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.
- ffhhj 5y agoIs it possible to grow crystals in moulds to give them custom shapes?
- svachalek 5y agoYou can influence the shape, I'm sure, but the geometry is mostly dictated by the molecules. These cube shapes are just how NaCl "wants" to bond, while other molecules may form hexagonal prisms or other shapes.
- rsfern 5y agoYes! The turbine blades in jet engines are single crystals of typically Ni or Co based alloys that are grown in a mold. It’s more of a directional solidification process though, I don’t think you could grow a NaCl crystal from solution like this in a mold https://www.appropedia.org/Single_Crystal_Turbine_Blades#Manufacturing_Process_and_Crystal_Growth https://www.appropedia.org/Single_Crystal_Turbine_Blades#Man...
- Borrible 5y agohttps://en.m.wikipedia.org/wiki/Chemical_garden https://en.m.wikipedia.org/wiki/Chemical_garden
- invalidusernam3 5y agoAssuming 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 5y agoI don't think a cheese grater would work? A hammer would be the tool I would go for.
- jsjohnst 5y agoThey make salt graters that look very similar to cheese graters. I have one I use with a big block of salt.
- darkwizard42 5y agoSeems 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!
- ttoinou 5y agoLooks really good. My three chemicals for crystal growing are ADP https://en.wikipedia.org/wiki/Ammonium_dihydrogen_phosphate https://en.wikipedia.org/wiki/Ammonium_dihydrogen_phosphate and MKP https://en.wikipedia.org/wiki/Monopotassium_phosphate https://en.wikipedia.org/wiki/Monopotassium_phosphate and Alum https://en.wikipedia.org/wiki/Potassium_alum https://en.wikipedia.org/wiki/Potassium_alum but probably table salt is cheaper..
- mellavora 5y agoCareful using Xerox scans to create your posts...
- isoprophlex 5y agoThose monopotassium phosphate crystals look gorgeous! Any tips for places to buy that salt?
- ttoinou 5y ago6 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__ 5y agoAt school we had a sodium crystal that was around 15cm in diameter. A teacher said, they found it in the woods.
- trulyme 5y agoI assume they were being sarcastic? Unless I'm missing something, such a crystal couldn't survive the humidity of the woods for long.
- sannee 5y agoPossibly an artificial "salt lick" [1] that got displaced from its original position. [1] https://en.wikipedia.org/wiki/Mineral_lick https://en.wikipedia.org/wiki/Mineral_lick
- philipkglass 5y agoCalcium 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 https://www.youtube.com/watch?v=AO67MnZaAvQ
- BuildTheRobots 5y agoDo you know how safe the resulting crystals are to handle?
- philipkglass 5y agoI 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.
- leoc 5y agoParents! Are your teens getting into "salt"? Know the signs.
- at_a_remove 5y agoI have often wondered what sorts of crystals that you can grow at home that are relatively hard, sturdy, long-lasting.
- dekhn 5y agoCrystallography, 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.
- perlgeek 5y agoI know in 2D there are patterns that tile aperiodicly, compare https://en.wikipedia.org/wiki/Aperiodic_tiling https://en.wikipedia.org/wiki/Aperiodic_tiling If the same holds true in 3D, maybe some of these proteins simply do not form crystals. Sucks to be a PhD student hitting such a protein.
- ulzeraj 5y agoI’m ashamed to confess that licking those pretty cubes was the first thing that passed through my mind.
- bl4ckneon 5y agoIt's ok, I too had the immediate though of licking it. "hmm I wonder if licking a flat salt cube is more satisfying than just normal salt..."
- ridgeguy 5y agoHey, no shame! A friend gave me a natural halite (salt) crystal that has beautiful purple coloration from natural radiation. Not radioactive, but purple mainly due to displaced electrons that formed color centers. It had great sharply defined edges and faces. For awhile. When visitors remarked on the specimen, my wife often explained that it was a natural salt crystal. Nobody could resist licking it just to be sure. Still got a beautiful color, but it's got about the same feature definition as a gummy bear...
- jrockway 5y agoWelp, 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.
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- markdown 5y ago> uniodised table salt Well that ends the experiment for me before it even began. AFAIK by law, all salt sold in my country is iodised.
- robocat 5y agoThere are lots of other uses for salt where it won’t have iodine e.g. pool salt, dishwasher salt, industrial salt, etcetera.
- deleted 5y ago[deleted]
- vixen99 5y agoI guess you could have extra fun and do this: https://www.thefreelibrary.com/Removing+iodine+from+iodized+salt.-a0115225326 https://www.thefreelibrary.com/Removing+iodine+from+iodized+...
- voldacar 5y agoThe rest of the content on this website is simply amazing. I'm so glad stuff like this is still out there on the internet. Nothing clickbaity or exploitative, just really detailed instructional knowledge on an interesting niche subject. Check out his copper sulfate crystals if you want something really visually impressive: https://crystalverse.com/best-way-to-grow-copper-sulfate-crystals/ https://crystalverse.com/best-way-to-grow-copper-sulfate-cry...
- errcorrectcode 5y agoCopper sulfate crystals grow huge. I'm fairly certain this was included in one of those DIY kits that took weeks / months to grow.
- pvaldes 5y agoJust a footnote. Remember that copper sulfate are highly poisonous to molluscs, fishes and crustaceans, and could kill pets also, so if you have it, store the stuff and saturated solutions in a safe place and -don't- discard it in the sink.
- b0rsuk 5y agoI think the best part is not the recipe itself, but the error handling of the article. It goes into detail into what conditions are optimal, what kind of tools to use, how various mistakes look like (with photos!).
- jkestner 5y ago! I know what I’m doing this weekend with my crystal-obsessed daughter and the bag of copper sulfate I forgot on top of the fridge.
- sydthrowaway 5y agoI wish there was a directory of sites like these.
- majjam 5y ago
- RattleyCooper 5y agoThat's what I said, sodium chloride... sodium chloride... that's what I said...
- scrubs 5y agoOutstanding instructions. And explains why my earlier attempts failed eg. using string. I'm gonna do this with my kid
- kunalpowar1203 5y agoWow thanks for sharing this. Have always wanted to do this ever since I read the first blog on growing crystals [big time procrastination there]. Please share your experience and steps if any for other salts. I am super interested in the blue of Copper sulphate.
- kunalpowar1203 5y agoNever mind. You already have it. https://crystalverse.com/growing-copper-sulfate-crystals-extended-guide/ https://crystalverse.com/growing-copper-sulfate-crystals-ext... :)
- beebeepka 5y agoNatrium chloride
- detaro 5y agoSodium chloride
- alexfringes 5y agoOnce, I accidentally grew a bed of salt crystals in a plastic tumbler left on a windowsill. Sadly I can't find the photos but they were closer to rectangular and clearer than the "bad" examples mentioned in this post. Diameters reached ~500mm on the large ones. Was I vastly luckier than I realized at the time, or is it all a bit easier to get right if you're not aiming for completely freestanding crystals (vs. a bed)?
- genocidicbunny 5y agoWere the conditions significantly different from what the author described? I would imagine if it was relatively cool but also humid, you may have just matched good conditions for growth. So you probably did get lucky, but depending on the conditions maybe not extremely lucky.
- foxfluff 5y agoOk I need to know.. how does one accidentally grow half-a-meter crystal? And how much does that weigh? And what kind of plastic tumblers do you have for that? :D
- perth 5y agosalt
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- foxfluff 5y agoI'd like instructions for growing quartz crystals at home.
- SergeAx 5y agoDihydrogen monoxide is the key component of this process.
- skocznymroczny 5y agoWhen I was a kid, it was very popular school project to grow copper sulphate crystals. They have a very nice blue color.