Emission/Absorption Laboratory

 

 The purpose of the exercise is to help you understand the emission and absorption of light energy as it interacts with the atoms of certain elements.  To achieve this goal, visit the following web site and follow the instructions given there and here.  In addition, answer the questions posed on this sheet. 

 

Go to - http://phys.educ.ksu.edu/

 

You should see a page that says “Visual Quantum Mechanics”.  Find and click on the “Simulations” button.  Scroll down to find “Spectroscopy Lab Suite”; then find and click on emission or absorption (eventually, you will look at both of these). 

 

Scroll down to find the directions given at the site.  Match spectra and energies for at least three of the known elements.  Do this for both emission and absorption (you will have to go back to the Spectroscopy Lab Suite page). 

 

Report or answer the following: 

1.        Give three (even though there are more than three transitions, just report any three) transition energies (in nanometers and electron volts, eV) for the each of the three elements you choose.  (Set up data using a table as shown below.)

2.        Perform a “print screen[1]” operation on one of the spectra.  Be sure to show your match of the energy levels.

3.        Briefly describe how these transition energies relate to the structure of the atom. 

4.        Explain why the spectra for the different elements are different. 

5.        Briefly explain the difference between absorption and emission. 

 

You need not write up a lab report in our usual manner - simply turn in the printed page from above, and answer the questions. You may perform this experiment by yourself, or with one other person.  I will not accept papers from groups larger than two!  If you choose to work with someone else, only one copy of the "report" needs to be submitted.  The "report" is due at the end of your lab period.   

 

A plug-in called shockwave is required to run this site.  The computers in the campus computer labs are equipped with shockwave.  If your personal computer will not show the graphics depicting the spectra, it may be that you do not have shockwave. 

 

 

Element	First Transition Energy	Second Transition Energy	Third Transition Energy
Helium	### nm; ### eV	### nm; ### eV	### nm; ### eV

 

Occasionally, the graphic portion of the page will not print properly.  If this happens to you, just draw a quick sketch of the graphic right on the page that you printed.  I want to be sure you know what this page looks like, and hopefully, how it relates to the things we’ve been discussing in class.