Abstract
"Electromagnetic radiation is the fundamental carrier of astronomical information. Spectral features serve as the fingerprints of the universe, revealing many important properties of objects in the cosmos such as temperature, elemental compositions, and relative motion. Because of its importance to astronomical research, the nature of light and the electromagnetic spectrum is by far the most universally covered topic in astronomy education. Yet, to the surprise and disappointment of instructors, many students struggle to understand underlying fundamental concepts related to light and spectroscopic phenomena.
This dissertation describes research into introductory college astronomy students’ understanding o f light and spectroscopy concepts, through the development and analysis ofbothinstructionalmaterialsandanassessmentinstrument. Thepurposeofthis research was two-fold: 1) to develop a novel suite of spectroscopic learning tools that enhance student understanding of light and spectroscopy and 2) to design and validate a Light and Spectroscopy Concept Inventory (LSCI) with the sensitivity to distinguish the relative effectiveness of various teaching interventions within the context of introductory college astronomy.
Through a systematic investigation that included multiple rounds of clinical interviews, open-ended written surveys, and multiple-choice testing, introductory college astronomy students’ commonly held misconceptions and reasoning difficulties were explored for concepts relating to: 1) The nature of the electromagnetic spectrum, including the interrelationships o f wavelength, frequency, energy, and speed; 2) interpretation of Doppler shift; 3) properties of blackbody radiation; and 4) the connection between spectral features and underlying physical processes. These difficulties guided the development of instructional materials including six unique
“homelab” exercises, a binocular spectrometer, a spectral analysis software tool, and the 26-question Light and Spectroscopy Concept Inventory (LSCI).
In the fall of 2005, a multi-institution field-test of the LSCI was conducted with student examinees from 14 course sections at 11 colleges and universities employing various instructional techniques. Through statistical analysis, the inventory was proven to be a reliable (Cronbach’s alpha = 0.77) and valid assessment instrument that was able to illustrate statistically significant learning gains (p < 0.05) for most course sections, with students utilizing our suite of instructional materials exhibiting among the highest performance gains (Effect Size = 1.31)."
