At Sammamish High School, we've identified seven key elements of problem-based learning, an approach that drives our comprehensive curriculum. I teach tenth grade history, which puts me in a unique position to describe the key element of authentic problems.
What is an authentic problem in world history? My colleagues and I grappled with this question when we set about to design a problem-based learning (PBL) class for AP World History. We looked enviously at some of our peer disciplines such as biology which we imagined having clear problems for students to work on (they didn't, but that is another blog post).