Getting Students to Explain their Solutions

When I started my physics career, I had two excellent resources. 1) My math skills were solid. 2) My spacial reasoning were also solid. This got me very far in physics. My largest downfall was that I was not good at explaining the results of my work. I often dreaded the last one or two question on Professor Brüning's problem sets that asked to delve deeper into the results of the calculations. Over time, I have improved my abilities in this area significantly over my career. I improved by doing lots of problems, explaining my solutions and my thought process with my peers, and being forced to expand my understanding when teaching others. Of course understanding the results of a calculation is one of the most important skills a physicist needs and I want my students to be good at it.

Furthermore, in the job market employers are always looking for scientist with good communication skills. As much as I want them to wow their professors at university with their robust answers, I really want them to be comfortable explaining their thought process in the written word. To be able to show future employers that they are exemplary scientific communicators.

To do this,

• The meaning of a solution is linked to the process of getting there so I ask my students to explain their solutions. 
• I go through a problem solving unit with my physical science students that promotes verbalizing their thought process.
• I model explaining my solutions as much as I can remember to do it slash have time to do it.

For this post, I just want to focus on getting my students to explain their solutions. 

I just want to know and I want them to know their thought process. If they make a small angle approximation I want to know why they did? To get an analytical solution. Because the book does it. Because the pendulum can only be displaced by a small angle. I want to know why.

As an incentive I make it part of my rubric.

• 2.0 The solution to the problem is justified through the language of mathematics and using clear and concise english to explain each step.
• 1.8 The solution to the problem is correct, but it lacks a sufficient explanation mathematically or otherwise.
• 1.5 The solution contains minor errors. Such as a transcription error.
• 1.0 Contains a major error.
• 0.5 The question was attempted.
• 0.0 The question was not attempted.

I know that marks are a poor incentive in the long run, but I don't know how else to initiate my student into the habit. I've also toyed with the idea of not grading them on the content of their explanations, but just insuring that they are there. Some students struggle with understanding the material and if they battle it out on their problem sets then I'm cool with that. I want it to start a conversation with my students. I haven't been good at this yet, but it is something I'm working on. 

Examples to come, hopefully.

Later gator. JMS