Adventure Fiction/Space Opera - The technology and science are secondary to the plot, which is often very grandiose, much like operas and horse operas that were popular at the time (the root of the latter name). Gadget Fiction - The technology/science and the struggle of the inventor to create/discover/explain it are the source of the conflict in the story. Social Science Fiction - The effect of the technology/science on society is the source of the conflict in the story. Adventure Fiction/Space Opera: Man invents car, gets into a car chase with a villain. Gadget sci-fi: Man invents car, holds lecture on how it works. Social sci fi: Man invents car, gets stuck in traffic in the suburbs.