As part of National Chemistry Week, seventh grade students at DaVinci Junior High School in Davis, CA saw rainbows everywhere they looked when students from the Sacramento City College (SCC) Chemistry Club came to visit.
The scientific question posed to the students was “What is the nature of fluorescent light? Is it just like sunlight?”
Each student in two of Ms. Barnes seventh grade science classes was given a paper template to make a foldable spectrometer ((http://publiclab.org/wiki/foldable-spec) and a piece of a DVD that acted as a diffraction grating.
After 10-20 minutes and with the help of four SCC Chemistry Club students, the seventh graders had all made functioning spectrometers. When a student pointed the spectrometer at a light source (or at reflected sunlight), that light was separated into its component colors much like what happens when light passes through a prism. Students confirmed what they already knew about sunlight– that it was composed of all of the colors of the rainbow.
As additional light sources, the SCC Chemistry Club brought gas discharge tubes that contained four different elemental gases: hydrogen, helium, neon, and mercury. These gases appear to be one color, but when the students looked through their spectrometers, they could see that the light emitted by each element was not just one color and not a full rainbow. Instead they saw a few to many distinct colors or lines, called a line spectrum, for each element. The relationship between these lines and the movements of electrons in atoms was discussed with the students.
Students also held or taped the spectrometers over their cell phone or laptop computer cameras to take pictures of the spectra.
The students were then asked what they had observed about the nature of fluorescent light. Students learned that fluorescent light is not like sunlight and much more similar to the light emitted by atoms: fluorescent light is, essentially, a line spectrum of mercury from the mercury gas contained in the tube.
“This was a great opportunity to give students a tangible and fun way to experience science,” said Dan Gruber, President of the SCC Chemistry Club. “Hopefully, we were able to turn some young minds on to chemistry, and science in general, because this is our next generation that is just starting to form their interests that will last them for the rest of their lives.”
That’s when the students got truly creative. One student taped the spectrometer over one eye to become a “rainbow cyborg”. Several students in one class taped DVD pieces over their eyes to improvise their own “rainbow vision” while students in another class taped the pieces of DVD over their cell phone and laptop cameras to take pictures of the rainbows.
“It was fun and rewarding to be a part of teaching the kids about spectroscopy and properties of different forms of light. I love their creativity and excitement!” commented Nicole Ackerman, one of the members of the SCC Chemistry Club.
National Chemistry Week is organized by the American Chemical Society (ACS). The SCC Chemistry Club is chartered through ACS whose local affiliate is the Sacramento Section.
For more information about this project or if you are interested in scheduling a classroom visit, please contact Bill Miller, Professor of Chemistry at Sacramento City College, at firstname.lastname@example.org.
By Bill Miller