Lasers are a unique sorce of light which are necessary for certain demonstrations of light. They produce a single wavelength of light, which is emitted in a single direction. Many optical phenomena require those properties.
However, the human eye is able to see certain wavelengths of light more easily than others. Light in the red spectrum is the easiest to produce with lasers, however it is a color of the visible spectrum that humans have difficulty seeing.
Red lasers produce better results in optics demonstrations compared to older methods such as sodium light. However, the results are still fuzzy and difficult to see. However, green lasers are now cheaply available and they produce brighter and clearer results.
Poor results and high set up costs have led to fewer optics demonstrations in the high school setting. This website explains several demonstrations which are more accessible than traditional counter parts. They require a green laser, items which are commonly found in schools or homes, and other cheap and readily available supplies.
We would like to thank the Early Undergraduate Research Program for funding us and giving us this opportunity, as well as our school, Buffalo State College and the Physics department.