What do students learn from a classroom experiment: Not much, unless they write a report on it

The authors ask whether writing a report on a classroom experiment increases a student's performance in an end-of-course test. To answer this question, the authors analyzed data from a first-year undergraduate course based on classroom experiments and found that writing a report has a large positive benefit. They conclude, therefore, that it is important to constructively integrate classroom experiments with some form of assessment or homework in order to realize the maximum benefit from them.