After completing a science unit on transfer of energy, including how chemical energy from a battery is converted to electrical energy; electrical circuits; and transformation of energy into sound, light, or heat; the students in Mrs. Finlay's fourth-grade science class were challenged to use what they learned to solve a problem. The students engaged in the engineering design process they had been using to develop and test a device that required a complete circuit. Mrs. Finlay supplied batteries, wires, light bulbs, buzzers, and switches. The students could also include their choice of additional materials. Mrs. Finlay used this project to assess the NGSS fourth-grade performance expectation 4-PS3-4: Apply scientific ideas to design, test, and refine a device that converts energy from one form to another (NGSS Lead States 2014) [Note: This is a hypothetical scenario]. This article describes how the students brainstormed ideas to solve the problem, choosing what they thought would be the best solution. Throughout the process, whenever misconceptions surfaced, Mrs. Finley helped the students revise or refine their ideas to move them beyond their preconceptions to the scientific ideas they would use in their planning.