http://www.youtube.com/watch?v=eUB4j0n2UDU

This is a fun video about the logic behind hard sciences such as biology, chemistry, geology, etc. Most of it should be common sense, but sometimes you only decide it's common sense after you've heard it.

This is related to Richard Dawkins tangentially, but there is no mention of religion or other such controversial topics (unless you believe in bigfoot and aliens that might have created the pyramids).

I think it really packages thought processes you should go through when deciding on whether something is fact or fiction very well. I think it would be great to show to kids.