5 ms·
> Indeed, table salt is often used in kids’ experiments to demonstrate crystallization. It’s a simple activity, but the results are disappointing. I remember t
by 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?
- dekhn 5y agomainly to get more crystals and as a growth medium for existing crystals.
- sumtechguy 5y agohehe 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 5y agoDid you do the version where you let the super saturated solution cool down slowly, and then drop a single grain of sugar into it?
- sumtechguy 5y agoThat was the plan. But never got to the 'super saturation' point where it would no longer melt in. Knowing what I know now I figure the temp was too high. Least I got an A as I had pounds of crystals. We added flavoring and coloring to some of it and gave most of it away.
- spike021 5y agoWe 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 5y agoCould 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.
- derobert 5y agoIf you look for canning / pickling salt, that should be free of both iodine and anti-caking agents.
- nitrogen 5y agoIf you can get "kosher salt," IIRC that should be non-iodized.
- nielsole 5y ago> I’m not sure about Kosher salt; it might contain anticaking agents
- ComputerGuru 5y agoDiamond brand kosher salt has no additives or anti-caking agents.
- btilly 5y agoThe article says that iodized table salt doesn't work, and isn't optimistic about kosher salt either.
- outworlder 5y agoWhat about dishwasher salt? It's usually 100% sodium chloride.
- jldugger 5y agoI dont think anyone in the US sells that tho.
- nitrogen 5y agoI'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.
- dghughes 5y agoI was expecting distilled water to be the most critical part but it was even mentioned.