Equipment List:
    Spectroscopes
    Hydrogen Source tubes
    Power supplies for the tubes
    Mercury calibration sources
    Tensor lamps

Purpose:
    To measure the wavelengths of the visible spectrum of hydrogen for as many orders as possible and compare to the accepted values.

Introduction:
    Elements emit light when excited. When only one element is emitting the light, the wavelengths of emitted light are not continously distributed but are only emitted at certain discrete wavelengths. Explaining why this is so is a great triumph of early quantum mechanics.

Try this link:

Procedure:
Set up your equipment. Check the alignment; your instructor will hopefully be of help. Start out by using the box-like mercury source that puts out a strong green line. You can check the calibration of your spectroscope (and your ability to use it accurately) by confirming that the wavelength of the green line is 546.074 nm. The darker the room and surroundings, the better your chance to clearly see the spectrum of hydrogen for more than one order. The visible wavelengths have the colors violet, blue-violet, blue-green, and red. You should be easily able to see at least three of these. The red wavelength is particularly easy to observe; maybe you should start with that color and see if everything is working properly.

Data:
Record the angles for all visible lines. For each order, you should record the data for each individual wavelength at BOTH sides of the center maximum and then average those two values (what does this accomplish?). Ideally, you would have a total of sixteen angles; one angle for each of the four visible wavelengths of the Balmer series. Get four angles for the first order left side, four more angles for the second order left side, four angles for the first order right side of the central maximum, and four angles for the second order right side. That's four different angles for each of the four different wavelengths.

Analysis:
Compare your measured values of the four wavelengths to the accepted values as calculated from the Rydberg equation for the Balmer series.