What is the difference between humour and satire? Or are they just the same thing but different words?
They aren't the same thing.
Humor is pretty simple; it's well...humor. When the author makes you laugh to make a point or simply to entertain, that's an example of humor.
Satire, on the other hand, is often mistaken to always be humorous. But in reality, some satire isn't supposed to be humorous at all. Oxford Dictionary defines satire as "the use of humor, irony, exaggeration, or ridicule to expose and criticize people's stupidity or vices, particularly in the context of contemporary politics and other topical issues." So while satire can sometimes be humorous, there are other ways to write satire. An example of non-humorous satire would be Jonathan Swift's "Modest Proposal." So basically, satire is when the author seems to support a certain idea on the surface, but uses irony to actually convey a deeper meaning that is usually opposite that of the surface idea.