9. Why do we add energy? Shouldn’t the gas glow all by itself without any help?

10. Yes, but the electrons will populate the lowest energy state. In order to see the spectra to the fullest, energy is used to populate excited states and let the electrons cascade down through the orbits, producing as many characteristic photons as possible.

11. http://jersey.uoregon.edu/elements/Elements.html Periodic Table with Spectra

15. http://jersey.uoregon.edu/elements/Elements.html Periodic Table with Spectra

16. What would an absorption spectrum look like to a computer?

17. Periodic Table with Spectra What would an absorption spectrum look like to a computer? An exercise for the reader

23. Click here to view a temperature adjustable continuous spectrum