Reason 864 why I love my job:

you get to play with craft supplies in the service of teaching.

I'm doing clay mineralogy in soils class this week, and I realized that maybe if the students actually saw mock-ups of the different clays we're talking about (chlorite and smectite and kaolinite and fine-grained mica), it would make more sense, the differences between them, especially re: shrink-swell ability.

So I bought some "foamies" (self-sticking foam) and some beads and some Play-Doh. (did you know Play-Doh contains wheat? So if your child is allergic to wheat, you should not let him eat it, I suppose...or at least that's what I assume from reading the warning on the side of the label).

Play-Doh is also one of the most evocative smells I know. I opened the can and I was back sitting at my mom's kitchen table on a rainy summer day, trying to make horses out of Play-Doh.

I made ball-and-stick models with play-doh and toothpicks (which is harder than it seems) for the silicon and Mg/Al basic units, and then used foam sheets to represent the tetrahedral and octahedral sheets.

For the shrink-swell clays, I have the individual "clay layers" made, and can insert one to many "layers" of "water" (blue foamie) in between them to show how expansive clays expand and shrink.

I'm particularly proud of the fine-grained mica; it has potassium ions between the different layers and that holds them together. So there is a layer of white pony beads sticking the 2:1 silicon: aluminum layers together.

I never would have thought all those years in Brownies (and later, Girl Scouts), and day camp crafts and vacation Bible school crafts would have a payoff in my career, but they do.