I spent nine years going to lectures at university. During those lectures no one tried to convince me of anything. They generally took the form of a bored lecturer getting through his notes for the nth time just to cover the syllabus. Even when the lecturer in question had authored the recommended text he (nearly always a he in physics thirty years ago) was seldom enthusiastic. On the rare occasion when a younger lecturer had retained some personality or enthusiasm he still wasn't trying to convince us of anything, just eager to share a bit of interesting knowledge and keen that we should be as interested in it as he still was. Sadly I never went to a lecture by Richard Feynman or anyone of his calibre.
In contrast the preachers I have witnessed giving sermons have more of the Derren Brown about them. They never appear to be what I would describe as simply spreading the good news. They sound and behave like snake oil men (yes nearly always men) selling something. There are plenty such sermons to choose from on the internet if you don’t want to witness one in person. I recommend that believers of all persuasions go and listen to sermons from religions or sects that are not their own. It's easier to see what's going on then. They range from the obvious mental soporifics of ritual and chanting (usually retained by the older established religions such as Islam, Catholicism, Judaism, High Anglicanism, Orthodox Christianity) to the spitting evangelist playing with the emotions of the audience.
This epitomises the contrast between teaching and preaching to me. Preachers are often self-evidently trying to convince us of something, teachers are generally neutral. It's true that good teachers try to inspire an enthusiasm for the subject but they are never trying to convince us of anything.
Evangelical Christians in the US tell us that science is a belief and that 'evolutionists' (a term used to embrace all scientists as far as I can tell) are trying to subvert our children and our morals. They seek to place teaching and preaching on the same stage. Just comparing the two types of performance I think that we can judge the truth.