Emission Spectra

In my final presentation, I plan to explore and display a simple method for classifying elements by their wavelengths. This method is to look at a chemical element's emission spectra. Just like absorption lines, all chemical elements have a particular set of emission lines, which are essentially the opposite of absorption lines. Instead of measuring the energy/ photons absorbed by an electron, scientists measure and mark the energy radiated by electrons when they drop back down to low energies from "kicking" up to high energies. These lines appear as bright lines of color on a dark background instead of black, color-absent lines.

Emission lines are very easy to produce in a laboratory, which is one reason I am presenting them for my project. In the outside world, emissions are produced by street lamps, neon signs and florescent bulbs. In the wonderful world of space, nebulae and some stars can radiate emission lines as well.

Example:

Hydrogen emission lines are radiated by a hot, thin hydrogen gas, and appear at the same wavelengths as the hydrogen absorption lines. 
From "Astronomy! A Brief Edition," J. B. Kaler, Addison-Wesley, 1997.


Interesting Find: Whilst looking around the internet for helpful information, I found this great simulation made by (I think) the University of Oregon. It allows you to look at the specific emission and absorption lines for every element on the periodic table and the corresponding wavelengths of each line. 

Emission/ Absorption Simulation