Hello! I took this course (forensic science, right?) about a year back so forgive me if my memory is a little rusty but I can answer this with some confidence. I'll define each of these types of evidence, hope this helps!
1. Physical evidence is a pretty much exactly what it sounds like; it's really any material object or matter that ties into the investigation. For example, fiber found at the scene of the crime would be considered physical evidence, as would blood splatters or biological matter.
2. Documentary evidence, again, is basically what it sounds like. It's a document that played a role in what is being investigated or hashed out in a court of law. This could be someone's last will and testimony, a printed email, or even a receipt.
3. Demonstrative evidence is a form of evidence that could explain what happened and how, such as a graph, model, or pictures.
4. Testimony is a statement taken from a person educated in the subject that is being discussed. Giving testimonies is one of the roles of a forensic scientists, as their opinions carry weight due to their education and experience.
I hope this helps! Good luck!
