Here you are, the LAST POST (for now) about vinegar and baking soda. Enjoy!
We don’t advocate violence here, but we had trouble coming up with a good name for this one that wasn’t weapon-like. It was either grenade or bomb. I guess ours were more like bombs since we didn’t throw them, but I think next time we’ll toss them. You definitely want to put them down and not stand too close, just in case. Alternatively, if you’ve got a bunch of little geeks, have them don their kid-sized protective eyewear.
For our last baking soda and vinegar experience at alumni camp we did it in little film canisters. Many of them had such tight lids that they just leaked a little when the pressure got too great, so you’ll want to test your canisters before doing it with the children. You want them to pop off, not ooze under pressure.
After camp I found this great Instructable that adds a little twist: a small plastic bag part that prevents the baking soda and vinegar from coming into contact with each other until you throw the grenade. I think this is a fabulous idea. I also think it would be great to add paint or watercolor and create a paper or fabric target of some kind.
Need a refresher on the chemical reaction itself? Baking soda + vinegar = water + carbon dioxide + sodium acetate (more or less).