Automatic identification of student misconceptions and errors for truss analysis
The use of concept inventories in mechanics education has great potential to identify areas where interventions are either working or not working for particular concepts. Concept inventories are validated measures and easy to implement. Where intended interventions are not working, there is potential for enhancing student learning. This process of implementing concept inventories to quickly measure the effectiveness of a teaching intervention is shown through a case study with Mechanix. Mechanix is a sketch recognition tool that tutors students on drawing free-body diagrams (FBDs) and truss problems. It is being developed at Texas A&M University. Students sketch their answers on tablet computers as they would normally on paper or with a mouse and a standard computer monitor. This provides a system with a low learning curve. Mechanix is able to provide immediate and intelligent feedback to the students; it tells them if they are missing any components of the FBD and if their answers are correct. The program tells the students whether their solved reaction forces or member forces are correct or not without actually providing the answers. The concept inventories indicate the concepts that Mechanix is already more effective at teaching than tradition lecture only. Since Mechanix captures the students answers in real-time, their errors and misconceptions can easily be identified and corrected if appropriate feedback is built into Mechanix. Mechanix is still in development and its feedback system can be further refined to more precisely target the concepts the students should be learning. Future versions of Mechanix will automatically provide instructions with a description of the errors their students are making and the concepts they may be having difficulty with. This will be provide in an easy to use interface where professors can quickly obtain a real-time update on their students' performance and then adjust their teaching approach and examples as needed. The concept inventories are an effective tool for determining which concepts are most difficult for the students and should be targeted for feedback within the Mechanix software. The concepts inventories provide quick identification of concepts students do not understand. Results from the concept inventories indicate that for the Statics Concept Inventory, almost all pre-scores are at the level of random guessing. This means that professors using the Statics Concept Inventory for students who have not had statics, it may not be necessary to do a pre-test. Our results do indicate that students may be familiar with the direction of forces at pin and slot joints. The concept inventories are indicating that Mechanix needs to better support students in learning how to separate bodies for free body diagram and the directions of forces at pin-in-slots. 2012 American Society for Engineering Education.