Tuesday, December 21, 2010

Comparing Crystals

Note: I'm including this activity, even though I continue to struggle to get it to work myself.  I like the idea, and know that crystals can be grown from each of the following solutions, even if I can't grow them.  I can grow great Borax and Alum crystals.  The rest of them... not so good.  If anyone has any advice, please pass it my way. 

When leading a study of minerals, you'll talk about the repeating crystal structure of minearls.  Unfortunately, most mineral samples (especially those found in the classroom) don't provide students with the opportunity to see those crystals and the different shapes they can be. 

Consider making up a set of crystal sticks so students can see some of the different shapes crystals can take on.

Here's how you do it:
Make a super-saturated solution* of any of these solids in water:
--Table salt
--Rock salt
--Sugar
--Epsom salts
--Borax
--Baking soda
--Alum

Place a length of pipe cleaner into the solution and let sit overnight (or longer, depending on the solution). 

In the morning remove the pipe cleaners and allow them to dry.  Make sure you keep the nametags with the crystals, so you know which is which.


*To make a super-saturated solution:
Begin with boiling water in a jar.  Stir in as much of your solid as you can, until no more will dissolve and it starts to settle to the bottom of the jar.  You'll need a different amount of each solid to get the job done.

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