Friday the 8th grade science teacher was absent, so I got to teach one of the 8th grade sections. I’ve taught 8th grade, and they had just started learning about telescopes, so I taught them about light. I handed out diffraction gratings to the students, and then used spectrum tubes to show the different colors from different elements. I showed neon, argon, oxygen, and hydrogen. The tubes are placed in a transformer that sends high voltage through them to excite the atoms and they give off photons as the electrons return to their ground states.