This is basically our dissolving rocks recipe made with black food coloring, but it's fun for the holidays. I made a dough of baking soda and water. It needs to be wet enough to be stick together but not so wet that it won't hold its shape. I just added a little water at a time. Then I tinted it with black food coloring to make it look like coal.
I had some plastic Christmas rings from Walmart that worked perfectly as surprises to hide inside.
I formed the dough around them and let them dry overnight.
|Maybe I should have called this activity dissolving reindeer poop.|
I also gave them medicine droppers and spoons and this activity kept them busy for a long time. Longer than it took to dissolve the coal, because they kept pouring and mixing and making potions.
If you want more Christmas science fun, be sure to check out the Christmas science challenge hosted by Inspiration Laboratories and Science Sparks.