playdough to build the mountain. We DID need a lot though (approximately 24 cups of flour!) so make sure you have enough ingredients on hand. We had to make a handful of batches, so I raced my kids to see who could finish a batch quicker. We didn't add any food coloring as we were going to paint it later.
When we were happy with our volcano's shape, we got out the brown tempera paint and the kids went at it. Some type of gray-ish color could also work, but I'm happy with the way ours turned out.
After painting, we decided to add some trees. We ventured out onto the playground to gather small sticks and twigs. For the leaves, we crumpled up green tissue paper and poked the stick through over and over again, overlapping layers of the tissue paper to make it appear bunched up. We then stuck the twig into "Sculpt-It" to make them stand on the cardboard. Any type of clay should work here.
The kids also wanted to paint in a river to make the landscape a bit more interesting.
Between using green paint or picking grass from around the playground, the kids voted to go for the "realism" approach and use real grass. Due to our summer drought, and lack of interest in ongoing grass-picking, I personally feel like green paint (or green tissue paper/construction paper) might have made a more appealing "grassland" effect, but this was the kids' project - not mine!
After many painful hours of waiting for our after-school kids to show up, it was time for the eruption! I had browsed through a number of different "recipes" for this reaction, but I ended up more or less winging it. I started with between 1 and 2 cups of water, to which I added some orange food coloring, and quite a bit of baking soda - possibly up to a cup. I also put in just a squirt of dish soap, as I was told it'd create a more pleasing "sudsy" effect. You can be the judge as to whether or not it helped!
After funneling in all of those ingredients, we moved the volcano out to the playground and carefully poured in some vinegar. It immediately started overflowing. We were able to add more vinegar at least 5 times before it stopped having reactions! The kids loved it, and I think there was an added element of satisfaction after they had been working on the project all day long.