All you need is some unused diapers, or pull ups (I had about a dozen left over from our potty training days), a few drops of green food coloring, and water (it's a good idea to chill it in the fridge ahead of time, for a more realistic snow feel). We've actually made fake snow from diapers before, but this is the first time we've tried making it green.
Harvest the sodium polyacrylate (the powdery stuff), from inside the diapers. Sodium polyacrylate is a hydrophillic (water loving), polymer, and what makes the diapers absorbent. It is non-toxic, though not edible, and you probably don't want to breath it in. I covered my face with a towel when removing it from the diapers.
Cut the diapers open, and lift up the cotton layer. The polymer powder will be laying underneath. All you have to do is dump it off, into a bowl.
Once you've collected the powder, pour it into a glass for a nice effect. You can leave it in the bowl, but a glass affords a better view of the transformation. Add a few drops of green food coloring to your chilled water (it's a good idea to have about four times as much water, as powder).
Pour the water into the glass.
Scoop your "snow" out of the glass, preferably onto a sheet of plastic, and have fun.
We found, that our "snow" not only absorbed the water we spilled, but the rest of the water in our cup, too.
It doesn't really feel like snow, more like cold, squishy plastic, but it's an awful lot of fun to play with.
Supposedly, you can let it dry out, and use it again. I'll have to let you know on that one. Which reminds me, our leprechaun jewels, from yesterday, did end up a very pretty, light green.
It's great to be a homeschooler.