Spectroscopy Lab - Avery Casey

Spectroscopy of Gases in a Tube
Avery Casey

ABSTRACT
    This lab was designed to demonstrate the basic practice of observing gases with spectroscopy. In addition to an online lab, students were shown 7 gases and, using observations and spectroscopy, identify the gases.

INTRODUCTION
     In 1857, Kurchoff discovered that each element has its own spectral signature. This discovery and the further development of spectroscopy has led to many achievements in the field of astronomy. Spectroscopy is frequently utilized in astronomy and reveals much about our universe. Observing galaxies and stars with spectroscopy reveals their chemical composition as well as temperature, density, and motion. This lab was designed to introduce students to the basic procedure for using spectroscopy.

METHODS
     To begin this lab, students completed an online segment on sapling learning. Afterwards, students were told to observe with the naked eye and diffraction grating to identify seven gases chosen by the lab instructor.

RESULTS AND DISCUSSION
Incandescent Lightbulb: The lightbulb shows a continuous spectrum. The light from the bulb appears white but emits a continuous spectrum.

Gas #1 - Krypton: This gas appears pinkish-blue when viewed with the naked eye. When observed through the spectrometer, there is a distinct teal line and a distinct teal line with most in the middle looking fairly continuous.




Gas #2 - Neon: This gas looks very bright red to the naked eye. When viewed with spectroscopy, most emission lines are red (brightest around 650) and yellow with one distinct blue line.



Gas #3 - Mercury: This gas appears blue when viewed with the naked eye. When viewing through the apparatus, I saw emission lines at 650, 590, 650 and 510nm.


Gas #4 - Helium: This gas looked peach-colored when viewed with the naked eye. Using the spectroscope I was able to see emission lines at 450nm, 465nm, 495nm, and 500nm.



Gas #5 - Sodium: Emits golden yellow color when viewed with the naked eye. When viewed with the spectroscope, I observed one yellow line at 585nm.


Gas #6 - Hydrogen: When viewed with the naked eye this hydrogen gas appeared bright white-blue. I observed lines around 560nm, 535nm, and 430nm.


Item #7 - Fluorescent Light bulb: Because of the emission lines, I expect that fluorescent bulbs contain mercury.

Based on
CONCLUSION

Spectroscopy is an important astronomical skill because it reveals many basic properties of stars and galaxies which we cannot directly photograph. Spectroscopy reveals properties such as composition, temperature, density, and motion. Because of its enormous importance in the study of astronomy, it is important for the astronomy student to understand this powerful technique.