This false-color scanning electron micrograph shows caffeine crystals. In plants, caffeine functions as a natural pesticide that paralyzes and kills some insects.
The main crystals were 400-500 microns long; however, this crystal group formed on the end of the larger crystal and measures around 40 microns in length. The judges selected this image because it's such an unfamiliar perspective: “It's a bright, intricate image of something that most of us experience every day."
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.