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Nicholls Chemistry
The Nicholls Chemistry Field Day is a one-half day field trip to Nicholls Chemistry where students complete college-level labs in chemistry and physics with our faculty. The chemistry portion of the field trip includes a session with three demonstrations. After that, the students go into the lab where they complete three lab experiments. The Demonstrations and Experiments are described below.
Demonstrations
Demo 1. Students look at a laser beam spot on a wall through diffraction gratings (“rainbow glasses”). They also pass a beam from a laser pointer through a diffraction grating. By comparing the distance between the first and zero order spots from a green laser vs. red laser pointer, students can see how a unit of length is associated with the color of light. The observations are explained in terms of constructive and destructive interference of waves. The class goes through a procedure for measuring of the wavelength for the red laser together. If students in the class already know trigonometry, a very brief derivation of the formula is presented; otherwise, students are given the working equation without using the sine function.
Demo 2. Students also use a handheld spectrometer to see the emission spectrum from the fluorescent lamp in the classroom. The observations are explained in terms of diffraction. If the students have already learned about electron configurations, they are shown how to look up the transitions responsible atomic spectral lines from the NIST Atomic Spectra Database, using the Hg 546 nm line of the fluorescent lamp as an example.
Demo 3. Students are shown how, using a fiber optic cable, to guide light from external light sources (fluorescent lamp and laser pointers) into the Vernier SpectroVis spectrophotometer, and how record the emission spectrum using the Vernier LoggerPro software. The principles of operation of the spectrophotometer are explained in terms of diffraction.
Experiments
Station 1. Students determine the wavelength of light from a green laser pointer using the same procedure in Demo 1. To add excitement to the activity, students are encouraged to think of ways to make their measurements as accurate as possible as a prize will be awarded to the group with the most accurate results.
Station 2. Students examine the emission spectrum from H, He, and Ne lamps qualitatively (by looking through a diffraction grating) and quantitatively (using a Vernier SpectroVis spectrometer, as in Demo 3).
Station 3. Using the Vernier SpectroVis spectrophotometer (as in Demo 3), students record the spectral lines obtained during flame tests of sodium and lithium salts.
Supporting Documentation
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