LAWRENCE, Kan. (AP) -- Lawrence school district officials have told an 8th grade teacher to change a lesson on slavery that included having some of the students wear mock shackles.

Mike Wormsley at Liberty Memorial Central Middle School has taught the lesson for years. The two-week role-playing exercise is designed to show students the roles of slaves and slave owners.

Part of the lesson required some students, including black students, to wear mock shackles in school.

District officials this year told Wormsley they understood the value of the exercise but wanted him to end the use of shackles because it isn't appropriate for school-age children.

The Lawrence Journal-World reports (http://bit.ly/11SosXL ) officials were concerned about the emotional impact of the shackles, but also thought the assignment could lead to abusive or inappropriate behavior.