This is one case from a book of case studies on co-operative learning. A chemistry teacher split her students into groups and had each group be responsible for one section of a unit in chemistry. When students were stuck or needed help she would not directly answer questions for them, but rather guided them with more questions. All but one of the groups succeeded in the task. The teacher did not step in to teach their section but rather had a class discussion about what could be done when a group didn’t get along. She let the students fail not only the project, but fail their colleagues who were still responsible for learning the material that they were supposed to teach.

Lotan, R. A., Shulman, J., & Whitcomb, J. A. (1998). Chapter One-Case Four: Do you let kids fail? In Groupwork in diverse
classrooms: A casebook for educators (pp. 24-29). New York: Teachers College Press.