Geissler Tubes/Emission Line Spectra Lab

Week 5 Observations: “Geissler Tubes”/Emission Line Spectra Lab
February 11, 2020
Purpose(s) of Lab:
To Observe the Emission Line Spectra of Various Elements/Molecules in Low Gas Density Geissler Tubes and take careful detailed notes on the characteristics and features on each Gas. This information will be used in the future in this class.
Apparatus used in the Lab:
We will make use of the following apparatus in B316:
* Low Gas Density ‘Geissler’ Tube power supplies and stands
* A set of “Geissler” Tubes of differing Elemental and Molecular Gases. The identity of the gas is marked on the tube.
* A set of spectroscopes able to produce a spectra of the gas to be observed
You can work in groups during the observations. BUT THE MATERIAL WRITTEN IN THIS WRITE-UP NEEDS TO BE UNIQUE TO YOU. TAKE NOTES CAREFULLY.
Task 1: Practice using the Spectroscope on one Geissler Tube set up next to the Spectroscope
1 Properly aim the scope on the tube insuring that an Emission Line Spectra can be seen to the side of the tube image. It is crucial that you can see and note the emission lines produced.
2 Adjust the amount of light entering the tube to be able to see the lines but not too bright so that they ‘smear out’ other lines
Task 2: Observe each Tube provided in the lab at each Spectroscope Setup
1 For each Giessler tube observe the spectra and write as many careful notes as possible about each spectra.
2 Mark where the ‘scaled numbers’ are compared to most prominent emission lines.
3 Note the observed overall color of the tube without the Spectroscope as well.
4 Write down the Element/Molecular Gas name on this write up
5 Proceed to each Tube and repeat this task.
Task 3: Make sure your Notes are complete and Every Tube has been Observed carefully. Compare with your colleagues, if you wish.
Name of Element/Molecular Gas_____________________________Mercury_________________
Description/Notes on Spectra
The spectra of mercury as observed from the spectroscope is not a continuous spectrum but rather one that has a light spectrum composed of nine different lines. Upon measurement of their respective wavelengths, it shows that the different lines show the following different values; (1) 623.4, (2) 615.2, (3) 579, (4) 577, (5) 546.1, (6) 502.5, (7) 435.8, (8) 407.8, and (9) 404.7. Among these spectral lines, there are two adjacent lines for the yellow and violet colors.
Without the spectroscope, however, the tube seems to glow in blue-violet color.
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Name of Element/Molecular Gas________________________Argon_________...