In my experience, most kid's science kits and "make your own" whatever end up being very disappointing. But when Theo picked out this kit for Dora for Christmas, and I okayed it, because it looked like something she'd enjoy.
It required boiling water, so not entirely DIY.
Photo on the box - spectacular, right?
Actual size of grow your own crystal. Hmmmm. It's also annoying that the box is about four times larger than the size of the contents.