Exploring Wavelength: A Quantitative and Qualitative Analysis of LEDs

In this lab, students will explore the relationship among wavelength, frequency and energy, as they observe white light and LED light sources, using a spectroscope. Students will also observe the effect of color filters on white light and LED light sources, using a spectroscope. Students will qualitatively explore the effectiveness of several filters, through analysis of their predictions versus their observations of the visible light bands observed before and after adding color filters. In the pre-lab, students will graphically discover the mathematical relationships among these three variables. Students will also have the opportunity to analyze these mathematical relationships through calculations. "Exploring Wavelength: A Quantitative and Qualitative Analysis of LEDs” aligns with the Green Chemistry Principle “Safer Chemistry for Accident Prevention.” Specifically, by eliminating the use of the flame test, students are not exposed to 1) higher hazard salts, 2) potentially hazardous methods used to increase the intensity of the flames – such as the use of methanol, or 3) gas or ignition sources.