I found a great blog for crafts with toddlers, they had a lot of info on volcano projects so I got some ideas from there, including making our "erupting" volcano out of play dough- genius! I encourage you to check it out by clicking on the underlined "volcano projects" above.
First we made 2 pictures from scrap book paper, brown paper bag, colored tissue paper, glue & scissors. We made a regular volcano & an underwater volcano. It was fun excuse to work with him on cutting & gluing. I just let him go at it, and he had a blast.
Next I put on Go Diego Go, Season 2 Episode 14 " Giant Octopus to the Rescue" (thank you netflix). It talks about volcanoes above & below water, and they even have an underwater volcano song. While he was watching the show I got the ingredients together to make homemade play dough (that we used to create our erupting volcano). I pre-measured the ingredients into different bowls, so he could help me make it quickly. I chose a no cook recipe from this great site: http://www.playdoughrecipe.com/ It has all kinds of recipes for play dough including flavors & edible versions.
After making the play dough we headed over to our cousins house to share our experiment with them. It was so fun watching the boys excitement as their volcanoes erupted. It was really simple, cheap fun and after the volcanoes bubbled over (several times) we let the boys play with action figures in the "lava". We put 3 Tablespoons of baking soda in the plastic cup inside the volcano. Next we mixed 1/2 cup white vinegar with 3 drops of dish soap & poured into the volcano. It immediately bubbled over. Try pouring the vinegar solution in a few times to keep it erupting. Plan to throw the play dough away, it gets pretty gooey.
We ended our day by heading to Rain Forrest Cafe. They have a Volcano Dessert, it comes out with a sparkler inside, way cool! So so good, of course I only had the ice cream, but the boys tell me the cake was delicious. It was a fun treat, and the look on Drew's face was priceless! Hope this inspires some fun educational days for you and your family :)