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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Borek on September 29, 2005, 06:49:33 PM

Title: bushes in solution :)
Post by: Borek on September 29, 2005, 06:49:33 PM

I have just remembered. Many years ago I was playing with simple yet fascinating experiment. You take a solution of sodium silicate and drop crystals of different salts into it - copper sulfate for example. Some red crystals gave the best effect but some of you where not even planned at the time when I did the experiment so please don't ask me what it was as I don't remember :)

What happens is that silicates precipitate on the crystal surface and they form a thin, semi permeable membrane. Water goes in, membrane breaks, solutions flows out, new membrane is created. Different salts give different shapes and different colors.

I have no reagents at hand now so I can't repeat the experiment, but I suppose some of you may have everything needed at hand (Wilco?)

Edit: these red crystals... I had potassium ferrocyanates (both) from some "Young chemist" set. So these are suspected.

Title: Re:bushes in solution :)
Post by: mike on September 29, 2005, 07:50:46 PM

Hey Borek, yes this is a great experiment, I actually did it in the lab yesterday, dilute solution of silicate plus any metal salts = silicate garden!

It is great fun  :)

Title: Re:bushes in solution :)
Post by: Mitch on September 29, 2005, 08:32:05 PM

Pictures anyone?

Title: Re:bushes in solution :)
Post by: mike on September 29, 2005, 08:39:21 PM

some silicate gardens..

Title: Re:bushes in solution :)
Post by: mike on September 29, 2005, 08:40:07 PM

..

Title: Re:bushes in solution :)
Post by: Borek on September 29, 2005, 09:09:30 PM

Super :)

But static pictures are half the fun - they look great when growing too :)

Title: Re:bushes in solution :)
Post by: mike on November 06, 2005, 10:38:17 PM

So inspired by the previous crystal growing experiments I have now made this cool sodium acetate tower, from a super saturated sodium acetate solution. The cool thing is it starts off as a clear, colorless solution and as you pour it out it solidifies to form these great towers, with no trace of the solution.

Title: Re:bushes in solution :)
Post by: mike on November 06, 2005, 10:39:32 PM

This would be a fun one to do with students (maybe this should go in education posts, sorry :))

I took the pics with my phone so sorry for the poor quality ::)

Title: Re:bushes in solution :)
Post by: AgG on November 07, 2005, 12:48:22 AM

neat stuff!

Title: Re:bushes in solution :)
Post by: constant thinker on November 07, 2005, 10:07:18 PM

Sweet. Are these compounds fairly easy to get a hold of and cheap. I want to try this expirement

Title: Re:bushes in solution :)
Post by: mike on November 07, 2005, 10:15:44 PM

sodium acetate I would have thought would be quite cheap and easy to get.

Sodium silicate (water glass) is probably harder to get (and a little more dangerous to work with. Some of the metal salts should be easy to get like copper sulphate etc, however some metal salts are toxic so make sure you check them out.

I think you can actually buy "sets" of these crystal growing kits from science/toy stores.

Title: Crystals
Post by: mike on November 20, 2005, 06:56:19 PM

Here are some copper sulfate crystals I have grown over the weekend.