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Basic Idea:

• Examine the spectrum of Hydrogen, and measure the wavelength of each visible line.

• 6

Equipment Needed (each setup):

	What:	How Many:	Where:
	Hydrogen tube	1	non-Majors storeroom, shelf PP3
	Gas tube power supply	1	non-Majors storeroom, shelf PP4
	Spectrometer (not the same ones used for 152!!)	2	non-Majors storeroom, shelf QQ2 - QQ4
	Wood drafting board	2	non-Majors storeroom, shelf J2
	Flashlight	1	ask Jeff
The following are placed on back right bench See location in picture below
	Pasco Sodium source (see picture below)	1	non-Majors storeroom, shelf DD3
	Light Aperture (see picture below)	2	non-Majors storeroom, shelf DD3
	Wood spectrometer platforms (elevate spectrometers for Sodium source)	2	non-Majors storeroom, shelf QQ6
The following are placed on the bench along the right wall See location in picture below
	Gas tube power supply	4	non-Majors storeroom, shelf PP4
	Assorted gas tubes: He, O2, Ne, Ar	1 each	non-Majors storeroom, shelf PP3
	2x2 diffraction gratings (slides)	The whole box	non-Majors storeroom, shelf KK4

Computers Needed?

• No.

• Location for setup (see this page for photo details). Note that only 6 spectrometers are set up. If 8 setups are needed, the sodium source can be placed on the instructors table:

  

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• Hydrogen source setup:
  
  • Place each spectrometer on two drafting boards; elevates to proper height
    
  • Stagger spectrometers on bench as shown below; that way, there will be less interference from other sources in the lab

  

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• All spectrometers need to be adjusted before (and sometimes during) each experiment
  
  • Remove stationary tube from holder.
    
  • With slit end towards hydrogen source, look through diffraction grating. Spectral lines should be parallel to slit.
    
  • Return tube to its holder. Swing telescope to the side, and look through diffration grating. Make sure tube is aligned parallel to source.
    
  • Look at spectra through the telescope. Make sure that cross hair is parallel to spectral lines on both the left and right side of the zeroth central image. Rotate the eyepiece diagonal to align.
    
• Sodium light source and aperture assembly; attach two aperature assemblies to source. Remove the two rods from the light aperature assembly (use a 5/32" allen wrench); this allows the spectrometers to be placed closer to the sodium source, necessary due to the size of the lab bench:

  Images courtesy PASCO Scientific.

• Sodium source setup:
  
  • Place on bench as shown above. Make sure the light isn't visible from any of the spectrometers. The Na light is very bright, and will interfere with the Hydrogen tube measurements if too close.

  

©	St. Lawrence University	Department of Physics

Revised: 06 Apr 06

Canton, NY 13617