Описать фото, вставив слова в пропуски: This is a photo of ... talking ... . Based on ......

This is a photo of two students talking their professor. Based on the formula the board, the students must have had a lecture on the theory of relativity. It looks to me as if the teacher is trying to explain the subject to the boys and the students could be trying to understand the equations. It’s hard to say for certain, but judging by their eager faces, the chances are that they might be making some progress in that direction. I can`t really tell, but they could be really interested in physics.