crystals

[Krysia Lee]

Hi
Does anyoe else out there use saturated potassium nitrate solution to grow crystals with Yr7. All the other teachers here use copper sulfate or alum. One teacher has requested the potassium. I read in the MSds that heating may cause expansion or decomposition and violent rupture of containers. Does this refer to sealed containers only? Should Yr7 do this prac when there are so many safer alternatives?
Krysia

[Ocean Breeze]

I am with you on that one Krysia

No need for K NO3

Ask to see the teachers risk assessment of the prac. That usually puts the ball in your court, as you can then suggest "substitution".

If they really want the K NO3, maybe prepare a crystal of it before hand, for students viewing only

[noona]

We only use Copper Sulphate and reuse it over and over again.
I keep a bottle just for this prac.

[kl23]

I like growing borax crystals with junior students. Justt make up a sat solution and then get the student to make a shape out a pipe cleaner, suspend it in the solution for a few days and then pipe cleaner shape gets crystals all over it. They can then take this home as borax is fairly safe unless you start eating it. You can also get students to add food colouring to the solution and they can grow coloured crystals. Good prac to make around christmas. Nice for decorations.

[noona]

Hi Kl23
Thanks for the tip I will have to try it

[Rita]

We use saturated potassium nitrate at times. No problems so far. Crystals grow in plastic petri dishes.

Rita

[Ian]

Potassium Nitrate might be OK for EVAPORATION methods of Crystal growing, but I would be cautious about heating it. (It is one of the components of Gun Powder (saltpetre), I believe.) Also, in general, it is not a good idea to grind nitrates, so after the crystals have grown, be careful how you get rid of them.

I would generally prefer to use something a little less hazardous, myself.

Year 7 kids will probably be more excited about blue crystals than clear ones any way

cheers
Ian

[Krysia Lee]

Hi Everyone
Thank God it's Friday!!!!!!!!!!
thanks for all the replys. I managed to pull the pin on the heating of the potassium nitrate. I got her to mix a little Benzoic acid and metho on an overhead projector sheet and then the kids watched as the metho evaporated and beautiful crystals grew. Now they're onto the copper sulfate. I've passed on the Borax and pipe cleaner idea and it was well recieved.Good one Kl23
My prep room is on a seperate level to the teachers staff room, this is both good and bad, however it becomes easy to feel like I'm the totally alone. Then when I have a question/problem theres all you guys out there and I LOVE it. You all have so much knowledge I am in awe of you.
Thanks for your help and enjoy the weekend.
Krysia

[Ocean Breeze]

I hate to mention this while everyones having such crystal fun, but I would not use BORAX for a yr 7 class either ... unless its a demo.. .

Due to the Health Effects section.. exposure to young people who are developing /have fertility, long term effects.

I know that a few other schools have also substituted other substances when a prac calls for borax.

Its not as "safe" as we would imagine. I use it mixed with honey at home to kill insects, ants, cockroackes, anything that ventures in for a feed really is gone really quickly.

Other information available is that in Europe, its listed as S60 and S61 where the S60 relates to impared fertility, and the S61 relates to birth defects. (We usually follow their lead within a few years)
Its also an S5 poison.
Concentrations of more than 8.5% are the issue.


So saturated solutions to make crystals, as well as the solid form of borax are or much greater concern.

I hate whats happening now, that its bought freely from supermarket shelves in the laundry section, to be used as a drain cleaner or a laundry aid, then flushed down the drain into our oceans. This is boron we are talking about.
Is it any wonder that we are having global ecological issues?

Just dont eat any fish that come out of the harbours!

I will get down off my soapbox now ...sorry

But have a look at the msds' in the links below when compiling your risk assessment for the prac, and consider substition, limiting student exposere, doing demo. etc.

We use sugar, alum, copper sulfate and sodium chloride for our crystals


http://www.duralite.com.au/safety/BORAX ... YDRATE.pdf

http://full.<URL removed, see forum rules>/edu/MSDSWinNe ... 0469972506

[Ocker]

Yah! Rain-bow could not have said it better!

[Rowyrow]

just wanted to show my magnificent crystal growing ability. I prepared these to show the year 7 class befor they start to grow their own. The one on the left is two weeks old and the one on the right is only one week ahhh my babies I want them to be monsters! oh and thats a 5c piece just for comparison! wish I had taken pictures of the seed crystals they started from.
How would I go about storing these?

[Ocean Breeze]

Thanks Ocker.
Your school the same re borax?

[sammy]

Thanks for the info Rainbow-Sky

I was just about to get out the borax when I read your reply. Some gr8 info and food for thought

[Ocean Breeze]

Hi Sammy thanks

So many issues to think about.., thats why Risk Assessment BEFORE pracs are required now.. a really good thing in my opinion.

Some of us no doubt come across teachers that have ALWAYS used some chemical or another, sometimes its hard to change old ways.
Thankfully we dont have any issues here at my school -for the time being at least

But hey,I remember when we went to the dentist and to keep us kids quiet, we were given a few beads of mercury to roll around in our hands..and to take home!!
In school s we used to use red lead...would go home covered in the dust!
Wooden toys were painted a nice bright yellow colour! (lead based)., and asbestos sheeting was the building material of choice!

[Ocker]

And blow through blowpipes to reduce lead oxide back to lead while choking on fumes.
But hell there's nothing wrong with me

[Ocean Breeze]

Oh yes, other beautiful crystals that I remember!

One of my favourite toy ornaments when I was young, was a cute barometer poodle.
Sat on my bedroom window sill

It was supposed to tell you if it was going to be WET or DRY.

It was a pink poodle when it was humid/damp, and blue when it was hot & dry.

VERY clever... except that when I sucked on it, I can remember this wierd, astringent but addictive taste.

Could only suck it for a second or two at a time, but being young I must have developed a taste for it.

Yep, you guessed what it was painted with! Cobalt Choride!

Nothing wrong with ME either!

[RosalieM]

Just looking for suggestions for junior kids (years 5/6). Their teacher has asked me to help them grow some copper sulfate crystals and some potassium nitrate ones as well. After re-reading this thread I wonder if we should just use sugar and salt for these kids? My hesitation with copper sulfate is that they do it in yr 7 so I don't want to steal the high school teachers' thunder... Any further ideas/suggestions?

[dime]

Not sure abaout how well the sugar and salt crystals grow, but alum ones grow well. Non hazardous too.

[RosalieM]

Thanks Dime. Do you know if you can put food colouring in them to make it slightly more exciting? Could give each group a different colour...

[dime]

Can't say that we have tried. But it would be worth a go. The small amount of colour needed shouldn't stop the solution forming crystals (hopefully).