Launch Interactive Share to Google Classroom When you flip a light switch on and off, you are closing and opening a circuit. A circuit is the path that electricity follows. Play the interactive above to learn more. Grades: 3 4 5 6 7 8 9 10 11 12 Subjects: SciencePhysical ScienceEnergy Transfer Collection: InteractivesActivitiesSimulations Series: NASA OnlineNASA Science Simulations