Family is a major theme. Sarah comes into the family and has to form new relationships. Another theme is adaptation. She has to adapt to a new place and a new way of life. And love, as she gradually falls in love with the family and the place.
It's because the story is set in a specific historical period and might draw on real events or social conditions of that time to create a fictional narrative.
The characters. Sarah is a complex and interesting character. Her journey from a 'plain and tall' stranger to becoming part of a family is engaging for 4th - graders. It gives them a sense of how life was different in the past, which is what historical fiction is all about.
The book 'Sarah Plain and Tall' represents historical fiction for 4th graders in multiple ways. The setting of the prairie and the rural lifestyle are typical of a certain era in history. The family's anticipation and then adjustment to Sarah coming into their lives show the social norms of that time. The language and the daily activities described, like cooking over a wood - burning stove or writing letters, are all things that transport 4th - graders into the past, making it a great piece of historical fiction for them.
Actually, 'Sarah Plain and Tall' is purely fictional. The author came up with the story and its elements without drawing from real-life events or people.
Well, 'My Antonia' is quite similar. It portrays the immigrant experience in the American Midwest, much like 'Sarah Plain and Tall' which also has elements of rural and family - centered life in a historical setting. 'The Witch of Blackbird Pond' is another. It's set in colonial America and has themes of a woman finding her place in a new community, just as in 'Sarah Plain and Tall' where Sarah has to adapt to a new family and place. And don't forget 'Roll of Thunder, Hear My Cry' which deals with family, race, and life in the South during a historical time, similar to how 'Sarah Plain and Tall' shows family life in a different historical region.