A spectroscope is an instrument that breaks up a beam of light or other electromagnetic wave into the various colors or wavelengths which are present, allows measurement of the wavelengths of the various components, and sometimes allows measurement of the relative intensity of these components. For visible light, the light is normally broken up (or dispersed) with either a prism or a diffraction grating.

The "Project STAR Spectrometer" we are using for this lab has a diffraction grating by the round eyehole where you look in. At the other end, there is a square aperture with a slit where the light enters (the slit is rather deep inside and hard to see). There is also a long curved scale calibrated in nanometers, 350-750, the wavelengths of visible light. The square aperture can be pointed out the window to examine the sunlight reflected off of the snow, or it can be pointed at fluorescent lights or other sources of radiation around the room. Do NOT point the instrument at the sun- too much light will come through it for safe viewing and you can hurt your eyes permanently.

Point your spectrometer out the window at the snow. Sketch the spectrum that you see, labeling your sketch with words for the colors and wavelengths. If you look very closely you can see a few dark lines in the spectrum, caused when the blackbody spectrum of the sun passes through the outer layers of the sun's atmosphere and is selectively absorbed.

Scattered around the lab there are several lamps which contain hot gasses of various kinds- hydrogen, nitrogen, neon, sodium, and so forth. Visit all of the different kinds (there are several of each kind to reduce waiting) and record the spectrum of each- the wavelength of each bright line and a verbal description of the color. Note if any lines seem much brighter or dimmer than the rest. For gasses which produce many bright lines, it might not be practical to record the wavelength of each.

Now, point your spectroscope at the fluorescent lights on the ceiling and record their spectrum. Can you identify any of the lines in the spectrum as probably caused by a certain gas in the tube? Can you identify enough lines that match to give you some confidence in concluding that that particular gas is actually found in the fluorescent lamp? The fluorescent lamp also has a continuous spectrum with all colors- not just narrow lines. Can you explain where this might come from? (Do this with the long fluorescent lamps in the lab- the short fluorescent lamps recessed in the ceilings in the hallways are somewhat different.)