Electrical circuits are difficult to understand. Novices tend to have inadequate understandings of what happens at the level of atoms and electrons, leading to difficulty predicting the outcomes of electrical circuits at the level of wires, resistors, and light bulbs. In this paper, we argue that integrating micro and macro representations of an electrical circuit can provide students with a better understanding of fundamental concepts of electricity. We then introduce Spark, an interactive multi-level simulation environment that enables learners to interact with representations of electrical circuit at both levels. The primary goal of our design is to familiarize students with electrical current, resistance, and potential difference in a circuit. We conducted a study with 17 university students that shows the ability of our design to improve novice understanding of electrical circuits. Our study offers evidence that learners are able to develop better understandings of fundamental concepts of electricity drawing on both micro-level and macro-level representations of an electrical circuit.