Students get excited about science when they investigate real scientific problems in the classroom, especially when the investigation extends over several weeks. This article describes a health-science problem-based learning (PBL) investigation that a group of teachers and teacher educators devised together for a group of fourth- to sixth-grade students participating in a summer science enrichment program at George Mason University in Fairfax, Virginia. As students participated in the problem-based lesson, they learned about diseases and how to live healthy lives while experiencing how scientists work. (Contains 1 figure and 1 resource.)