Light and Spectra: Procedure

1. Pick up one of the spectrometers and hold it so that the arrow is pointing towards the white light source (you should be looking into the narrow end; you will see a slit to the right of the numbers where the light should be coming through). What do you see? What does this tell you about the nature of white light?
2. Now point the spectrometer at one of the colored tubes. How is the spectrum different? How do the lines combine together to produce the light you see with your eyes?
3. Go around to each of the colored tubes. For each one, write down the name of the element and the wavelengths of the four brightest lines you can see. Use a table like the one below. Notice that the wavelengths are measured in nano-meters (or nm for short)--it takes one billion nm to make a meter!
   

   Data Collection Table

   
   
4. Now go into the hallway and point the spectrometer at one of the overhead fluorescent lights. What does this spectrum look like? On the chart below, write down the wavelength and color of the four brightest lines you see in the spectrum of the fluorescent light. Using the table you made above, identify the element(s) that are in a fluorescent bulb.
   

   Data Collection Table