Science, Tech, Math › Science Scientific Definition of a Closed System in Thermodynamics Print Viesturs Jankovskis / EyeEm / 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. 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. Learn about our Editorial Process Updated on April 09, 2019 A closed system is a concept used in thermodynamics (physics and engineering) and in chemistry. It differs from an isolated system. Closed System Definition A closed system is a type of thermodynamic system where mass is conserved within the boundaries of the system, but energy is allowed to freely enter or exit the system. In chemistry, a closed system is one in which neither reactants nor products can enter or escape, yet which allows energy transfer (heat and light). A closed system may be used for experiments where temperature isn't a factor. Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Scientific Definition of a Closed System in Thermodynamics." ThoughtCo, Feb. 16, 2021, thoughtco.com/definition-of-closed-system-604929. Helmenstine, Anne Marie, Ph.D. (2021, February 16). Scientific Definition of a Closed System in Thermodynamics. Retrieved from https://www.thoughtco.com/definition-of-closed-system-604929 Helmenstine, Anne Marie, Ph.D. "Scientific Definition of a Closed System in Thermodynamics." ThoughtCo. https://www.thoughtco.com/definition-of-closed-system-604929 (accessed March 29, 2024). copy citation