Tracy Wergley Graebener, a labor and delivery nurse, checks vital signs on a newborn at Virginia's Reston Hospital Center. Tamara Keith/NPR hide caption

itoggle caption Tamara Keith/NPR

Konarka uses this blue chamber to test solar panels. It re-creates light conditions at noon at the equator. Chris Arnold/NPR hide caption

itoggle caption Chris Arnold/NPR

A nurse tends to a patient at the University of Maryland Medical Center in Baltimore. The Bureau of Labor Statistics says nursing is the occupation that will provide the most new jobs over the next decade. Rob Carr/AP hide caption

itoggle caption Rob Carr/AP