Showing is almost always better than telling. I select aspects of a topic I’m talking about and then shoot footage or create a graphic to illustrate key points. When I interview other scientists, I try to think of ways to have them demonstrate something on camera. One tip is to always ask, “Can you show me what you mean?”, when doing an on-site interview (in a lab or at a field site). This question will often elicit some valuable footage for your movie project.
See this clip that resulted when I asked a scientist to show me what he meant by “relative buoyancy” of a floating marsh: