A guided-inquiry lab was developed to analyze the Balmer series of the hydrogen atomic spectrum. The emission spectrum of hydrogen was recorded with a homemade benchtop spectrophotometer. By drawing graphs and a trial-and-error approach, students discover the linear relationship presented in the Rydberg formula and connect it with the Bohr model of the hydrogen atom. The construction of the homemade spectrophotometer, the analysis of data, and the comparison between experimental and published data are discussed. The possibility of determining the Rydberg constant for deuterium as a possible extension of this lab is also discussed. (Contains 3 tables, 6 figures and 2 notes.)