I've been a fan of science fiction films since I was old enough to understand what space was, and the thing that's bothered me most about the, over the years, is the lack of actual science in many of them. To me the, much of the wonder of a sci-fi film is in being able to believe that it could happen. If what's being presented is clearly impossible, it loses credibility. On the other hand many great science fiction films have science elements that have very spurious credentials, such as time travel, faster-than-light space travel, or apes evolving into speaking, machine-building humanoids in just two thousand years. In films like that, the impossible or near-impossible is often there to construct an allegory for the purposes or satire or social commentary, so it doesn't necessarily mean it's 'bad' science fiction.
Also there's such a thing as entertainment value for its own sake - a film can be great fun but have no scientific credibility at all. The less you know about science, and the better you are at suspending disbelief, the easier it is to enjoy those films. So I thought it would be fun to draw up a graph, rating sci-fi films according to these two criteria.