At school this week we are learning about the letter V. I read somewhere before about the reaction you get when you mix baking soda and vinegar together. What I did was take 2 small clear plastic cups and I put put a small but big enough hole to pour the vinegar down at the bottom of one. Then I put a small amount of baking soda at the bottom of the cup with no hole. Then I put the one cup on top of the baking soda cup, so both tops of cups were meeting, and I taped it around the rims to keep them together. Then I poured vinegar into a different cup to pour into the whole. You have to pour the vinegar fairly fast to get the bubbles to come all the way out of the hole at the top. You can also add red food coloring to the vinegar so it resembles red hot lava. But the kids loved seeing the "lava" come out of the "volcanoe" They each had their own volcano to erupt.