Science, Tech, Math › Science Rainbow Fire Halloween Jack-o-Lantern Easy Multicolored Fire Pumpkin Share Flipboard Email Print Halloween jack-o'-lantern, featuring rainbow fire. Anne Helmenstine Science Chemistry Projects & Experiments Basics Chemical Laws Molecules Periodic Table Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 04, 2018 Create a spectacular multicolored fire pumpkin for Halloween! This rainbow fire jack-o-lantern is easy to make. Rainbow Fire Pumpkin Materials You only need a few basic materials for this project. The hand sanitizer contains alcohol, which is flammable, but self-extinguishes due to the water in the product. The boric acid or borax provides additional color to the flames. Carved Halloween jack-o-lantern (use a real pumpkin - plastic will melt!)Hand sanitizerBoric acid or borax What You Do Smear hand sanitizer all over the outside and inside of the jack-o-lantern.Dust the pumpkin with boric acid or borax. You don't need very much to achieve a nice colored effect. Just a light sprinkling will suffice,Ignite the jack-o-lantern.The flame goes out on its own fairly quickly as the alcohol in the hand sanitizer gets used up, leaving you with water. How It Works Boric acid or borax (either works) emit a green light when heated in a flame. The jack-o-lantern gives off a multicolored fire because you have the natural blue of the alcohol flame from the hand sanitizer, the green from the boric acid, orange light coming through the carved pumpkin, plus other colors from where the pumpkin juice mixes with the flame. The pumpkin flesh contains sodium, which imparts a yellow color to the fire. Tips and Safety You don't have to use boric acid or borax. Try other flame colorants for a different color blend.This is a fire project, so adult supervision is required.Be sure to perform this project on a fire-safe surface.You can extinguish the flame at any time by blowing it out.