Science, Tech, Math › Science Fire Writing Share Flipboard Email Print Anne Helmenstine Science Chemistry Activities for Kids Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists 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 January 15, 2020 Use invisible ink to leave a message. Reveal the message by touching a flame to the edge of the writing, causing it to burn away in smoldering flame. The paper is left untouched, except for the fire writing. Fire Writing Materials Potassium nitrate (available in stores or make it)WaterPaper (heavy, relatively absorbent paper works best, like parchment paper) Prepare Your Message Mix potassium nitrate into a very small amount of warm water to make a saturated potassium nitrate solution. It is fine if there is undissolved potassium nitrate.Dip a paintbrush, cotton swab, toothpick, fingernail, etc. into the solution and use it to write a message. You want to start the message or design at the edge of the paper. The lines of the message must be continuous since the fire will travel from the edge of the paper along with the writing. You may wish to re-trace the message to make sure there is potassium nitrate on all parts of it.Allow the paper to dry completely. Your message will be invisible, so I hope you know where it started!Touch the edge of the paper, where the invisible message started with the flame of a lighter. The message will ignite and burn in the smoldering fire until it is completely revealed. If you were careful only to light the edge of the message, the rest of the paper will remain intact. Disclaimer: Please be advised that the content provided by our website is for EDUCATIONAL PURPOSES ONLY. Fireworks and the chemicals contained within them are dangerous and should always be handled with care and used with common sense. By using this website you acknowledge that ThoughtCo., its parent About, Inc. (a/k/a Dotdash), and IAC/InterActive Corp. shall have no liability for any damages, injuries, or other legal matters caused by your use of fireworks or the knowledge or application of the information on this website. The providers of this content specifically do not condone using fireworks for disruptive, unsafe, illegal, or destructive purposes. You are responsible for following all applicable laws before using or applying the information provided on this website.