This is an exciting science experiment for 2nd-6th graders! There are two versions included, Leprechaun Rocks and Magic Rocks. It is essentially the same experiment, but one is themed for St. Paddy's day. A day or two prior to the lesson, the teacher mixes baking soda and colored water to make a rock paste. He/She then forms small rocks and puts a golden coin (I use a spray painted penny) inside. Students follow the handout to go through the scientific inquiry process and then put the "rock" in vinegar. To their surprise the rock disappears and a golden coin is left in it's place! This is a great experiment for students that have done "Changes" or "Rocks and Minerals" in science. For an extension, check out my "How to Catch a Leprechaun" writing assignment!