Science, Tech, Math › Science What Is Fire Made Of? The Chemical Composition of Fire Share Flipboard Email Print Christopher Murray / EyeEm / Getty Images Science Chemistry Physical Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry 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 10, 2018 What is fire made of? You know that it generates heat and light, but have you ever wondered about its chemical composition or state of matter? Chemical Composition of Fire Fire is the result of a chemical reaction called combustion. At a certain point in the combustion reaction, called the ignition point, flames are produced. Flames consist primarily of carbon dioxide, water vapor, oxygen, and nitrogen. State of Matter of Fire In a candle flame or small fire, most of the matter in a flame consists of hot gases. A very hot fire releases enough energy to ionize the gaseous atoms, forming the state of matter called plasma. Examples of flames that contain plasma include those produced by plasma torches and the thermite reaction. Why Fire Is Hot Fire emits heat and light because the chemical reaction that produces flames is exothermic. In other words, combustion releases more energy than is needed to ignite or sustain it. In order for combustion to occur and flames to form, three things must be present: fuel, oxygen, and energy (usually in the form of heat). Once energy starts the reaction, it continues so long as fuel and oxygen are present. Reference On Fire, Adobe Flash-based science tutorial from the NOVA television series.