(The Crucible is a really cool place, by the way - they do lots of classes for youth and adults, anything from paperworks, to stone carving and blacksmithing, with a big emphasis on anything fire-related. Check them out if you're in the Bay Area!)
Both of these bowls were tuned from very wet / freshly felled black acacia. The first day, I did all but the finishing on the smaller bowl, and roughed out the second, larger bowl (which was a bitch - with all those knots, it felt like I was holding a jackhammer at times!)
That also means that I was able to dry the smaller bowl overnight (and a bit more in the microwave in the morning), but I didn't get a chance to dry out the larger one before finishing it.
The smaller bowl, shown first, is 7" across, and wound up very thin: about 1/6" or so - thin enough that you can see a little light shining through that big knot at the bottom. Because we started with very wet wood, and the walls of the bowl are very thin, it developed quite a bit of warping while drying afterwards. You can see this really well on the first, side-on set of pictures, but it's actually not that noticeable in person.
The second bowl is 9" across, and about 1/3" thick. It was made out of a much more "ambitious" piece of black acacia, containing a big "crotch" (Y-shape, where a big branch splits off the main trunk of the tree). I decided to leave a bit of the natural bark exposed at the crotch, to accentuate that feature.
Because of time pressure (most other people in the class were only doing one bowl for the weekend), the more challenging nature of the wood, and lack of drying, there are a few more technical flaws with this piece, but overall, I do like it a lot.
There's a lovely convoluted knot at the bottom of the bowl - shown in a close-up at the end. The wood is actually carved and sanded perfectly flat there, but the folds in the grain make it look like a little maelstrom...