This is one of the easiest, most satisfying chemistry experiments you will ever perform for/with your kiddies.   I promise.

First, let me provide some background information for you.  This experiment is done with nothing more than alum and water, so (relatively speaking) it’s safe to do in your home.  Obviously, if you have small tasmanian-like children, you don’t want them to eat any crystals you’ll form…which is why I say *relatively speaking*.

Alrighty, historically speaking, Alum is a very interesting substance that is all around you and you probably don’t even know it.  If you can your own pickles, you know that it is used in pickling to keep them crisp.  Larger crystals are sold as crystal antiperspirant and alum is  a common ingredient in commercial APDO’s.  It also has antibacterial properties, and so has been used medicinally for canker sores, topically for cuts, and as an immunologic adjuvant in vaccinations.  Meh, you don’t want to hear about the last one.   Suffice it to say, man has been making good use of it for a few thousand years.  Now that we live in a state of abundance,  we play with it, forgetting all about its necessity derived origin.  Nevertheless, it IS great fun and educational, too.

This particular project is extremely uncomplicated, but provides a great entry into the next and slightly more complex experiment – geodes.  Fun, fun!

So, here is what you’ll need for this particular experiment:

A Pyrex (or like) Glass Measuring Cup or glass
1/2 cup Hot Water
2 & 1/2 tbl Alum (found in the spice section of the grocery store)

Instructions & Tips:
Because you want the alum to dissolve in the water, you’ll want to make sure the water is HOT.  I’ve done this a few times and I generally heat mine in the microwave for a couple of minutes in my handy Pyrex Measuring Cup.  From there, you’ll stir in the alum until it is completely dissolved.  If it hasn’t dissolved completely, you can heat the mixture in the microwave using 10-15 second bursts until it completely dissolves.  Next, cover your solution with a coffee filter or paper towel and allow it to sit undisturbed on the counter.  You’ll see crystals begin to form in just a few hours because of the amount of alum vs. water.  When you’re satisfied with them, or your water has evaporated, you can remove them. Now it’s time to ooh and aaah over your fabulous and super inexpensive creations.

If you’d like to discuss some simple scientific ideas that affect how this experiment turns out, you can list variables in the formation process.  For example, the amount variation of alum and/or water, type of container used (glass  vs. plastic) , whether your covering is tight and impacted evaporation, the water temperature, etc.

Finally, the variables are important concepts that translate well to another important life lesson – consequences.  How one thing impacts something else…or how your child impacts others.   After all, the temperature affects the water, evaporation rate, alum and glass – just as one persons actions ultimately affect everyone.