As a transparent sphere, a simple soap bubble can serve as an optical resonator, which means that with a little fluorescent dye, it can be made into a laser. Bubble lasers are soft and squeezable, and their response to ambient pressure can potentially be harnessed for sensing applications. For more on soap-bubble lasers and their liquid-crystal cousins, turn to the story on page 12 . (Image by Yuliya Evstratenko/Shutterstock.com.)