When it comes to 'how does science work' and how to deflect heaping hunk of hooey, I recommend the book 'Bad Science'. It's one of the best books I ever read, and helps people to see what is real science and what's heaping hunk of hooey with a science-y wrapper around it.
As for Captain known it all: My DH ran into one when he was on high school - His English teacher. English is not the native language where we come from (Netherlands), but my DH had been playing point&click adventures on the computer since he was six, in English (there games weren't published in Dutch). He started translating word by word with a dictionary, but got really good at English at the age of 13. Now at the age of 15 he was required to reach English literature. My DH picked the lord of the rings trilogy, and had no trouble reading it.
He got an F, because his teacher REFUSED to believe that he read it on his own. She believed that he had just ripped a summary from the library and was pretending that he had read this. My DH could never change his mind. And mind you, his teacher must have known he was good at English because he was pretty much a straight A student in the subject.
But my DH is also boneheaded at some times. He once claimed that the square of any number what the same as number x 2. No no, not number x number, but number x 2. Even when I made him calculate some examples to prove him wrong, he just shifted to 'well, it works for MOST numbers!'. I just told him 'look, I am better at math then you are, you know that. Can't you just take my word for it?' After a lot of bickering I gave him the silent treatment. It took him a long while to say 'well yeah, you're probably right'.
He also has this irritating tendency of, when a discussion starts to turn against his opinion, he shuts it down with 'never mind' and refuses to talk about it again. Once in my life, when he had been grating on my nerves for days with that kind of behavior, I cast myself in ehell and slapped him. While I have been baking in the 9th layer of ehell for that, it was a wakeup call for him.
Nowadays, when he has these moment again I just lock myself in the bathroom so that I won't be tempted to engage him. It helps.