Duck and Cover

     The overt message in "Duck and Cover" is that atomic bombs are dangerous and you can get badly burned by one. These bombs can fall at any moment; you should always be ready. When you see a bright flash, a atomic bomb exploding, you should duck and cover. This is the overt message because it was repeated over and over again in the video. In order to get people to duck and cover they used appeal to fear and bandwagon. They made it sound like it was definite that an atomic bomb was going to fall and that everyone else would duck and cover so why don't you.
     There is not a covert message in "Duck and Cover". The video was only created to inform people of what to do in case an atomic bomb were to fall.
     Since there is an overt message but no covert message this video was purely informative. Some messages may have come out of this video accidentally. For example, the civil protection agency, government and adults are there to help you always do as they say. (Sounds like the government is trying to say that if something happens, no matter what it is, you should always do as they say. Even if it is harm full to you are someone else.)