Commercial pop rocks is made with a compressed CO2 gas. But you can make them at home. The ingredients are sugar, baking soda, citric acid crystals, powdered sugar or corn starch, corn syrup, water and flavoring such as vanilla or fruit extracts. Combine sugar, baking soda, water and corn syrup in a pot. Combine well then add the citric acid crystals. Heat to 300 degrees, add your flavoring. Remove from heat and let cool on a baking sheet that has be dusted with the corn starch or powered sugar. When it cools break into small pieces.