(1) Once, long ago, I performed a cheapo science experiment which involved putting a bunch of salt into boiling water until it was hypersaturated, then letting it cool, then adding one grain of salt–and the whole pot crystallized. It was neat. I need to duplicate this experiement. Now it seems to me it was two cups of water and one cup of salt but I can’t remember, can’t find the experiment, even online, and don’t want to have to go out in the middle of the week and buy more salt if it fails. So if anyone has done this I would appreciate either a rough idea or the exact recipe.
(2) I have a crystal growing kit from The Kristal Corporation. It’s old, and I’ve lost the instructions. They have premeasured packets of various things to which you add hot water, then pour it over a rock in a plastic vessel. But, since I’ve lost the instructions, I don’t know how much water. In other words same question as above. More specifically I have:
“aquamarine” (looks like about 1/4 cup of granular green material)–monoammonium phosphate and “a strong food dye”
“amethyst” (about twice as much–so say 1/2 cup)–potassium aluminum sulfate and potassium chromium sulfate
“geode shells” (about 1/4 cup)–gypsum
“emerald” (the least of any of them, less than 1/4 cup, also finer granules)–monoammonium phosphate and potassium chromium sulfate
Any ideas on how much hot water to add to the above to make crystals?
(Note: I googled and found the company, several books on amazon.com, and a review of the product. No recipes though.)
(1)Put a cup of water in the pot. Slowly add water while stirring. Turn on the heat. Mix until it is all dissolved. The amounts of materials you remeber is probably right. Then let cool and add some more salt.
(2)I’d recommend starting with an equal volume of water, and adding all the crystal material. It likely won’t all disolve, so keep adding water slowly while stirring until it does. When it’s all dissolved, you’re good. It doesn’t matter if you have too much water, since the point is to evaporate all the water anyway. Only problem is if you have not enough water, then you won’t dissolve all the mineral.
All that matters is that the material is fully dissolved, the exact amounts don’t matter.
About 1: I don’t have exact numbers, but supersaturated solutions can contain huge amounts of the solute. It may be better to boil 1 cup of water, add salt gradually until it no longer dissolves, then add just enough water to dissolve the undissolved salt. Try to minimize the amount of steam that escapes – you might need to add some extra water to compensate for this.
The experiment will not work if there is any undissolved salt in the pot when you start to cool it. Also, since you probably want to make the salt ‘crash out’ by adding a single grain of salt to the mixture, be careful not to cool it too quickly or shock the mixture very hard. Pouring it into another vessel may make the salt crystallize, so try doing the experiment in a Pyrex container.
A general rule about crystallization is that the faster the crystals form, the smaller they will be. ‘Crashing out’ is undesirable if you want to use the crystals for x-ray crystallography or impress a lab supervisor. If you experiment with the amount of salt and cool the mixture very slowly, you may be able to produce very large, impressive salt crystals.
A supersaturated solution of sugar will also work. You might want to try Epsom salts too. Sodium thiosulfate (‘hypo’ or ‘fixer’ for black-and-white photography) produces very dramatic results but would be harder to obtain and is potentially toxic.
Use sugar instead of salt, and you can add food coloring, too. Get some kitchen twine or string, cut it into pieces which will fit into your solution container. Tie strings to a skewer, lay this across the top of the container, allowing the strings to hang in the container. The sugar will crystalize on the strings and make rock candy, which you shouldn’t eat if you’re diabetic.
Thanks! a concoction of “aquamarine” is now processing. We will see.
As to the salt, I used pretty much all I had, and it did not work. I’m blaming the nonstick cookware (it’s a handy thing to blame for all cooking failures). I have to try this with sugar. I believe rock candy might be very attractive to the person for whose benefit I am digging up these experiments. Mmm . . . crystals you can eat.