We improved a problem-based learning (PBL) program as an introductory course in chemistry. PBL in general encourages the students to manufacture something freely, but in chemistry field such a free activity is restricted by risks in experiments. In the new program, we separated manufacturing from PBL. We made a short laboratory experiments before discussion in the class rooms. Management of contaminated water in Fukushima Daiichi Nuclear Power Station was set as the problem to be tackled. Peer and self-assessment suggests that our program successfully motivated the students to learn chemistry. It is also suggested that appropriate subjects, corresponding to difficulties involved in e.g. a misbuilt robot or an inactive circuit, are indispensable to work PBL effectively.
