Presenter: Tyler Hill
Authors: Emily Heider, Tyler Hill
Faculty Advisor: Emily Heider
Institution: Utah Valley University
Recent research has demonstrated unambiguous positive effects of active learning in a variety of college-level courses. In large-enrollment, introductory science courses, active-learning can be a challenge. We report the assessment of a 50-minute active-learning activity related to light absorbance, reflectance and transmittance using portable, hand-held color sensors in large enrollment general chemistry courses. When white light strikes a surface, the object will be perceived as the same color as the wavelength of light reflected. If one or more colors are absorbed, and the rest are reflected, the object will appear as a combination of the reflected wavelengths. The learning objectives for the activity included: identify the band within the electromagnetic spectrum visible to the human eye; use colorimeter to determine the wavelength and maximum absorbance for a solution; use a reflectance meter to determine the wavelength and maximum reflected light; define absorbance, reflectance, and transmittance. In Spring 2018, 320 students in introductory chemistry completed a light reflectance/transmittance /absorbance minilab. Later, a different section of the course including 322 in the Fall 2018 semester completed alternate activities. To determine the efficacy of the minilab, five final exam questions relating to reflectance, transmittance, and absorbance were evaluated for both classes. With three of the five final questions showing statistically significant improvement at 95% confidence, we determined that the minilab hands-on activity was effective in helping the students better understand the relationship between these three properties of light.