An Affordable Self-Built Spectrometer for the Physics and Astronomy Classroom: A Useful Teaching Tool and Demonstration Instrument

The study of the electromagnetic spectrum, how light interacts with matter, and optical instruments such as lenses, mirrors, and gratings are important concepts in the Advanced Placement (AP) physics and introductory undergraduate physics and astronomy courses. The production, control, and analysis of light helps scientists to learn about the natural world. A spectrometer is an instrument that utilizes several components (lenses, mirrors, diffraction grating, or prism) that students commonly study in an introductory optics unit and can be helpful to demonstrate for students how light can be separated on the basis of wavelength. The authors designed and built a simple tabletop spectrometer. The layout is compact so as to make it easy to construct on a rolling cart to be easily transported for classroom demo or lab purposes. Additionally, we focused on keeping the spectrometer affordable, and discuss options for sourcing parts and scavenging for items in existing supplies. We constructed and tested two spectrometers, one at Susquehanna University in Pennsylvania and one at Providence College in Rhode Island. Similar to Isaac Newton leaving Trinity College in 1665 during the bubonic plague outbreak, the final testing and building of these spectrometers was completed in the basements of the authors’ homes amid the COVID-19 shelter-at-home orders.