For most people, a little girl with a lollipop isn't what comes to mind when thinking of a future scientist. When she was just 4 years old, however, Zhenan Bao was conducting her first science experiment at a park in her hometown of Nanjing, China. After handing her a lollipop, Bao's father, a physicist, asked her what would happen if she threw her candy into a nearby lake. Would it sink or float?