This experiment examines the absorption spectra of conjugated dyes using spectroscopy. The objectives are to study how the electronic energy levels of molecules vary with molecular size, and to compare theoretical models to experimental results. Absorption spectra are obtained for several dyes and the maximum wavelength is used to determine the energy difference between the excited and ground states. Theoretical models like the particle in a box model are applied to predict absorption wavelengths, which are then compared to measured values.