The concept of wave-particle duality of light and the relationship between photon energy and wavelength/frequency of light is important for the understanding the quantum mechanical model of the atom. While the mathematical relationship between photon energy and wavelength of light is not particularly challenging for students, the conceptual understanding of photon energy and, in particular, the photoelectric effect are often challenging for students in undergraduate chemistry courses to grasp. The following brief classroom demonstration was designed as a fun and effective way to reinforce the relationship between color/wavelength of light and photon energy as well as the relationship between photon energy and the kinetic energy of electrons ejected from the surface of metals in the photoelectric effect. This demonstration has been effectively implemented in small (30–40 students) classrooms for undergraduate General and Introductory Chemistry courses, and would also be applicable to high school Chemistry and Physics courses.
Steven Runyon (Sun,) studied this question.