A menu of items under physics can be obtained by clicking on the word PHYSICSnext to the word HOMEin the index line above. There, you will see entries for Brownian motion, global warming, sky colors, and other topics in physics that have captured my interest over the years. "Quantum Mantras" is a stand-alone study guide I prepared for my quantum mechanics students. About half of the guide focuses on Chapter 8, "Transitions." In this section, I show the relevance of the simple quantum-mechanical treatment of radiative transitions to the Heisenberg uncertainty principle and the phenomenon of the blue sky.