Duck and Cover is a "civil defense" film about how to protect yourself in a nuclear blast. It'd be a perfect MST3K piece now: the idea of protecting yourself from radiation with a newspaper seems amazingly naive and almost malicious. The repetitive "and stay in that position until the danger has passed", without ever explaining (perhaps deliberately) how to know when that has been reached.
"A is for Atom" is an astonishingly complete and easy-to-watch piece describing precisely how uranium and plutonium bombs work, and goes on to explain how wonderful atomic power will be in the future, providing power, helping farmers, and even producing medical miracles. Of course, to acheive these goals, the dangers of nuclear waste are never mentioned, nor the medical risks from using nuke materials as tracers in the body.
Although these have both disappeared from the Tooncast feed by the time I watched them (I'm a bit behind), I'd really suggest subscribing to this feed, as they seem to be picking some amazingly cool stuff from archive.org and providing it directly to my video ipod on a regular basis.