Visualizing Electric Fields Using Rubbed Balloons as the High-Voltage Source Available to Purchase

Developing a conceptual understanding of electrostatic interactions, electric fields, and Coulomb’s law is very important in undergraduate physics courses, and visualizing the electric field produced by charged electrodes offers a unique opportunity for students to initiate a basic understanding of electromagnetism. The experiment of visualizing electric field lines using seeds immersed in oil is typically used at universities as a lecture demonstration that needs big electrostatic machines to generate the necessary electric fields. Here, we present a simple experimental setup for the visualization of electric field lines that could be used at a massive scale in schools and universities. Our setup uses short filaments of paintbrush hairs immersed in sunflower cooking oil inside a plastic petri dish, and produces beautiful patterns of electric fields due to charged electrodes. Instead of using high-voltage generators to charge the electrodes, the high voltage is produced by charged balloons resting on isolated metallic pans...