How exactly does one turn sunlight and water into usable energy? If it were possible to ask any living organism on Earth this question, you could do far better than asking a biologist or a chemist, or any other human being for that matter, and take the question directly to a leaf. That’s the goal of biomimicry: to take human problems and ask nature “how would you solve this?” And increasingly, such questions are changing everything, from energy to information technology to the way we build cities.To see how a leaf works its magic, look no further than Dr. Daniel Nocera’s lab at MIT. Yesterday, Nocera’s team announced that it has created the first practical "artificial leaf", a synthetic silicon device that splits water into oxygen and hydrogen for fuel cells using sunlight just as a natural leaf does. Nocera’s leaf isn’t a perfect mimic of photosynthesis--for instance, it requires materials like nickel and cobalt that must be extracted from the earth, and catalysts that spur reactions that otherwise wouldn’t happen on their own. But it’s indicative of a growing shift in how humans solve big problems by looking to nature for elegant solutions rather than bending the natural world to their wills.