Joe Hynek may be the only student at Iowa State who carries a handbag for “scientific purposes.” On cloudless days, he wanders his neighborhood to test whether the purse, which is plated in thin solar panels and contains a lightweight battery, is absorbing energy from the sun. After three hours of direct exposure, the purse generates enough electricity to charge an iPod, camera, or cellphone. (The bag will also charge—more slowly—if placed next to a window.) Hynek is currently working on the final touch: a small display screen that will indicate when the purse is best angled for absorbing the day’s light.