Science, Tech, Math › Science Work Definition in Chemistry Share Flipboard Email Print The work required to carry a ball up a hill is the energy needed to act against the force of gravity. Michael Blann / 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 June 06, 2019 The word "work" means different things in different contexts. In science, it is a thermodynamic concept. The SI unit for work is the joule. Physicists and chemists, in particular, view work in relation to energy: Work Definition Work is the energy required to move an object against a force. In fact, one definition of energy is the capacity to do work. There are many different kinds of work. Examples include: Electrical workWork against gravityWork against a magnetic fieldMechanical work Key Takeaways: Work Definition in Science In physical science, such as physics and chemistry, work is force multiplied by distance.Work occurs if there is movement in the direction of the force.The SI unit of work is the joule (J). This is the work expended by a force of one newton (N) over a displacement of one meter (m). Mechanical Work Mechanical work is the type of work most commonly dealt with in physics and chemistry. It includes work moving against gravity (e.g., up an elevator) or any opposing force. Work is equal to the force times the distance the object moves: w = F*d where w is work, F is the opposing force, and d is the distance This equation may also be written as: w = m*a*d where a is the acceleration PV Work Another common type of work is pressure-volume work. This is work done by frictionless pistons and ideal gases. The equation to calculate the expansion or compression of a gas is: w = -PΔV where w is work, P is pressure, and ΔV is the change in volume Sign Convention for Work Note that equations for work employ the following sign convention: Work performed by the system on the surroundings has a negative sign.Heat flow from the system into the surroundings has a negative sign.