Last week the students spent several days collecting data using CPO lab equipment. The really enjoyed the roller coaster lab. The data showed that without a doubt the marble was rolling more rapidly at the end of the run than at any other point along the way. While the lab was not "open-ended", it did lead the students to other experiments they want to try. We are going to do so later this week as time permits. I wonder if anyone reading this does similar activities with their students.