The flashlights were needed to see the papers and colored pencils. The students found it difficult to match up the patterns at first. Hydrogen and helium are the easiest to identify. After a little discussion, students become aware that the lines don't fit perfectly because of experimental error. Then they learn to estimate and identify the elements.
Some gases are harder to see than others.
Start with hydrogen, helium,and neon. Very high quality diffraction grating slides can be purchased from Arbor Scientific. If anyone can improve on my accepted values, I'd appreciate your input. Carbon Dioxide 5. Unknown B 7.