Step One (Adults only) Prep your lemon by slicing the bottom off to make them sit flat. Flip the lemon over and slice out the core. If you are making an open faced volcano, slice the lemon in half. •Step Two Prepare extra lemon juice by slicing a second lemon in half and juicing it. Pour juice into a cup and set aside. •Step Three Place your cored lemon on a tray. Use your craft stick to mush the center of the lemon and bring out the juices. Be sure to keep the juice in the lemon! •Step Four Place a few drops of food coloring or liquid watercolors (do not dilute) in the center of the lemon. •Step Five Add in a good squeeze of dish soap to the lemon. This is not necessary but causes the bubbles to ooze and froth more and longer. •Step Six Add a spoonful of baking soda into the lemon. It should start to fizz. Take your craft stick and stir the lemon and lemon juice. It should start foaming really well as you stir it! •Step Seven To keep the reaction going alternatively add more baking soda, coloring, dish soap and the reserved lemon juice to the reaction. Squeezing the lemon to release the juices also enhances the reaction.
Got this one from: http://babbledabbledo.com/science-activity-kids-lemon-volcano