I provided a link to the pinterest pin below. AND I think we will try this again in the future. I mixed the paint too thin and didn't have a good dropper for the vinegar (the fizzy part).
In the end I just put baking soda and food coloring in a glass and poured vinegar in to show the cool volcano effect... and that was good enough for Lydia. Photos didn't happen for this project. Sorry about that.
We also had "hot dog squids" for lunch one day. It was fun and a big hit with Lydia. Miles didn't get to enjoy them in their squid form since he's not quite chewing.
Here are the pins: