Science, Tech, Math › Science Open System Definition in Chemistry What is an open system in science? Share Flipboard Email Print Mina De La O, Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments 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 February 06, 2018 In science, an open system is a system that can freely exchange matter and energy with its surroundings. An open system may appear to violate conservation laws because it can gain or lose matter and energy. Open System Example A good example of an open system is energy transfer in an automobile. Chemical energy in the fuel is converted into mechanical energy. Heat is lost to the surroundings, to it may appear matter and energy are not conserved. A system such as this, which loses heat or other energy to its surroundings, is also known as a dissipative system.