Visual Quantum Mechanics contains a series of simulations, tutorials, and pedagogy to help in the learning of concepts in quantum physics.  This material is suitable for a wide range of students.

Hydrogen Spectrum uses the spectroscopy lab to connect observed spectra to transitions between atomic energy levels.

Hydrogen Spectroscopy II adds to Gas Lamp Emission by allowing another energy level and the capability to zoom in on spectra, but only for the hydrogen spectrum.