A Simple Way to Teach Single Slit Diffraction Based on Edge Diffraction

Young’s experiment is hailed as a milestone in ushering a new understanding of the wave nature of light and is even taught at the high school level. Unfortunately, even the most cursory presentation of the subject of diffraction becomes confusing. The theory and equations based on Fresnel’s work appear arcane and incomprehensible to a high school student. In addition, students are not taught the significance of a phenomenon that has been observed since the time of Thomas Young: the bright band of light at the center of every single slit diffraction pattern. This paper presents a simple way to introduce the subject of diffraction based on Thomas Young’s original work and explains how the interplay of different components of diffracted waves from a single slit creates the broad central maximum.