A science fiction film has many features that differ from adventure, these features usually relate to a futuristic scenario. They usually include modern technology or advanced civilization. The reason being is to create an image for the future.
An adventure film differs completely. They usually contain fictional scenarios and characters, they are usually aimed at younger audiences. The reason being is because the younger generation find these types of film more enjoyable as they can usually relate to the storyline.
An example of a good science fiction film is 'Terminator 3', whilst this film is set only a few years in advance the technology is completely different. There is a lot of new machinery which completely change the feel of the film, for example, there are flying robots which shows the viewers that it is futuristic and advanced.
On the other hand, an example of an adventure film would be 'The chronicles of Narnia', this is completely fictional but for younger viewers is very gripping. It is set in a snowy world which exists on the other side of a wardrobe. This is a good adventure film as it's  very imaginative and really captures the younger generations imagination.


Terminator 3
http://www.youtube.com/watch?v=WeC-lGnajT0&feature=related

The Chronicles of Narnia
http://www.youtube.com/watch?v=pYcGFLgJ8Uo