1.  Lay your pizza box out flat. Use your razor knife to cut out the shaded portions shown in the diagram below. The two shaded squares should be approximately 1 cm on a side and they should line up across from one another. (Use a piece of corrugated cardboard as a cutting board.) Also make the U-shaped cut indicated in the diagram. Don't worry too much about the exact dimensions at this point. Almost anything in this experiment can be fixed with black tape!

Caution: Please be careful; these blades are sharp.

2. Now put the box together tightly using masking and black electrical tape.  The only light permitted in should be through the openings that you cut.

3.  Use a small piece of black tape to temporarily tape the shutter ("U" cut) in the "closed" position.

4. Now use two pieces of black electrical tape to define an approximately 1 mm (by width) entrance slit.

5.  Obtain a piece of plastic diffraction grating and orient it correctly on the box before taping it permanently with black tape. To do this, hold the box so that you can look into it through the square hole and point it vertically so that light from the fluorescent light enters the slit.  Hold the grating over the square hole with your index finger while still looking into the box.  You should see a visible spectrum (rainbow) to the right of the slit.  If a thin horizontal rainbow is observed then rotate the grating 90 degrees.  Try to handle the grating by the edges only as much as possible.
One you are satisfied, carefully tape the grating into the box (tape around the edges). Note: The entire spectrum should fit in the window ("U" cut).  If it does not, then the window may need to be enlarged.

6. Remove tape from "U" cut. This allows you to control the amount of light coming into the box.

Additional option:
    Tape a transparent piece of graph paper in the shutter opening.  If you have done it correctly, then when the window is part of the way open you should be able to view the fluorescent light spectrum and also read your x-axis.  This will allow you to make relative measurements of atomic spectra.

Source: Chemistry 105, General Chemistry Experiments, Department of General Chemistry, University of Illinois, Fall 200.
 

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