In Chapter 17, Clemantine remembers a class trip taken with her photography class, what purpose does her professor have for taking his class to the abandoned school?

In Chapter 17, Clemantine's professor takes his students to visit a school for Black girls that had only lasted a few years before townspeople attacked the building. During the trip, he asked his students to wander the building and create a story from what they saw and felt. This is the first time that Clemantine is told that the story, her story, is there; she just needs to take her time, look, and listen to find it.