How Did Cassie Come to See what It Was Like in the 1930s?

How did Cassie come to see what it was like in the 1930s?
Cassie came to see racism and 'how things are' in a number of incidents. Cassie still young was oblivious to racism that surrounded her. Throughout the book she learns more and more about the past and what is going on around her.
Cassie goes to Great Faith Elementary, one of the largest black schools in the county, an hours journey from her home, with her three brothers, Stacey, Christopher- John and Little man. Unlike the white children the black children do not have a bus, they walk to school everyday. …