What is the differences between documentary photography and conceptual photography?

nothing

Documentary Photography is when a photograph is taken with the intent to show something in the truest way possible without making any personal changes. Conceptual photography is usually a way to make statements. The main difference between the two is that one informs how things are and the other shows the audience what they want them to see. From the two examples the were shown to us from our instructor I would say that the one on the left is a Documentary photograph and the other one is a Conceptual photograph.