There is nothing incorrect for 1951 in "Duck and Cover," except a lot of unstated caveats. A thin cloth does help protect against thermal effects from an atomic bomb... but only at distances quite far from the actual explosion itself. Hiding under your desk will help you from the blast effects... but only in the <5 psi pressure zone. And so on. Radiation isn't an immediate factor at the distances "Duck and Cover" was advising you of — it is usually the shortest of all of the effects, and if you are close enough to be affected by it you probably are going to be in a world of trouble anyway from the intense thermal and blast. (The problem of residual fallout is a separate issue, one that comes several hours after the blast itself, and not one that would have preoccupied planners in 1951, for reasons I will get to.)

The idea behind something like "Duck and Cover" is that the people directly underneath a nuclear explosion are probably toast. However there are vast numbers of people in a region where the biggest problems will be either painful thermal effects (3rd to 1st degree burns) or "light" blast wave pressure (e.g. 1-4 psi, which will blow your windows in and cause earthquake-like damage).

So the idea is that instead of having, say, 100,000 casualties, with proper Civil Defense one can have, say, only 50,000 casualties. Which may seem like a trivial difference to you, but that's a lot of lives, and the question for the government officials at the time was whether it was irresponsible to not do what they could to save those lives.

Now the criticism of Civil Defense is that it gave people a false hope of survival, and that this could make people more willing to engage in nuclear war. I'm never quite convinced of the former (everyone I've ever talked to from that era seems to have been scared to death by the exercises and to have thought they were nonsense), and the latter is hard to gauge. But given that the Cold War was not a single-nation affair, given that what would happen was not predictable, and given that saving lives is one of the items listed under the government's responsibilities, one can take a non-sinister view of the whole thing.

Where people get confused especially today is that they think that "Duck and Cover" was meant to save everyone, or that it would work if you were directly under the blast point. But that was never really the intent. They didn't ever say, "oh, if you're right under the bomb, you're probably toast." I'm not sure what value it would have done to do that. For something like Civil Defense, you train everyone like they are in a potentially savable state, even if, when the attack actually came (if it ever did), you knew that wasn't going to be the case.

Now, it should be noted also that "Duck and Cover" was designed to be understandable by children, hence it doesn't discuss all of the caveats of survival, and it should also be noted that in 1951 it was assumed that a Soviet attack would be in the form of weapons around the size of the Nagasaki bomb (or maybe 2X larger or so), and in limited numbers. By the late 1950s, much less early 1960s, that strategic situation changed dramatically — there were weapons in the megaton-range (hundreds to thousands of times more powerful than Hiroshima), there were missiles (which give you less warning and no defense), there was a much smaller chance that anyone who was within a danger zone of multiple exploding nuclear bombs was going to get out of it by hiding under their desk or behind a sheet of thin cloth. Even then, though, a good Civil Defense program could cut the total losses down considerably, but the focus became more on fallout, because this would be what exposed the majority of people who were not otherwise in the immediate vicinity of the bomb explosion. (Fallout from thermonuclear weapons can cover vast areas and make them dangerous to be in for several days or weeks, and dangerous to live in for many decades.) Note that in the image I've linked to, they've given estimates as to deaths: 62 million dead from the bombs alone; 46 million dead from fallout if they don't take shelter correctly. Those 46 million are theoretically preventable deaths. That's a lot of people!

When teaching about Civil Defense, I like to juxtapose "Duck and Cover" with a 1956 pamphlet, "Mortuary Services in Civil Defense", just to show the difference in what talking about the practical effects of nuclear weapons looks like when talking to the "lay populace" and when talking to professionals. Granted, the difference in time is important, but imagining Bert the Turtle using mechanical excavators to dig trench graves seems to help the probable realities of this hit home.

Here's a portion of a letter written by Sen. Ernest Gruening (D-Alaska) on Jan. 17, 1962, to a Mr. James A. Miller of Fairbanks, Alaska. He wrote to Gruening on the subject of shelters:

... As for my own views on the disturbing and perplexing problem of protecting Americans against the horror of thermonuclear attack, I fear I must say I believe there is no protection except that of preventing such a disaster.

While I am aware the Department of Defense has provided the nation with extensive advice as to the construction of private fallout shelters, it is my feeling that this program gives our citizens an altogether false sense of security about the possibility of surviving a nuclear attack, and that this is fundamentally unwise.

In the first place, there are serious doubts, based on expert opinion, that the measures recommended by the Defense Department would provide any dependable security at all. I believe it is wrong for the Federal government to give our people the impression that constructing fallout shelters will save their lives. In fact, the Government cannot promise this, nor do I believe should suggest it. ...

I lecture on Duck and Cover. In a nutshell, no it's not as silly as it appears to us looking back on it from the 21st Century. (But yeah, people always laugh when I play it, since it does look ridiculous at first glance.) There's a couple reasons for this.

1. We tend to think of nuclear weapons in terms of the really giant thermonuclear beasts, like the 50-100MT Tsar Bomba. We're used to thinking, "Well, a nuclear weapon hits, we all die", right?

But the first H-Bomb was tested in 1952, a year after this movie was made. Nuclear weapons were much much smaller in 1951 (Fat Man was 2000x smaller than the biggest weapon tested). The best way to show the difference is to go to this website, which shows the blast radius for different levels of lethality for different nuclear weapons at different geographic locations. The bombs dropped on Japan at the end of WWII would destroy the just tip of Manhattan. The Tsar Bomba, by contrast, would level everything for miles around.

2. Look at that website again. If you pay attention to the different rings it draws, these correspond to lethality levels at various distances from the detonation site. If you're outdoors at Ground Zero, you're going to be incinerated. But if you're having a picnic with your family outside of the city (as in the example you think is silly from the movie), pulling a blanket over you could in fact protect you from burns. Moreover, even a thin layer of protection stops alpha (edit: and beta) particles. So it's not as ridiculous as it looks, even though everyone always laughs when it gets to that scene.

Likewise, there's a large blast radius from a nuclear weapon where you're not going to be incinerated, but are likely to get hurt or killed if you're standing by a window. So that part isn't silly, either. It really is a good idea to move away from windows and take cover behind a solid barrier if a nuclear weapon hits somewhat nearby.

3. Bomb shelters were actually a very reasonable way to survive a bomb blast. Since most nuclear weapons would be set to airburst, they were very destructive against surface buildings, but would not penetrate very far underground except right under the blast point. (The first nuclear weapons test only resulted in a crater 6' deep.)

A large part of the point of the movie was to get people to understand the air raid sirens and what to do in case an attack came with or without warning. With warning - evacuate to a bomb shelter. Without warning - do what you can to take cover (avoid windows, get behind a solid barrier, cover your exposed skin).

4. Another thing you have to consider is that Brinksmanship only works if both sides are actually willing to go to war. (If one side knows the other side will not retaliate, then the policy fails.) By issuing films like this, it not only prepared the American people for war, but also demonstrated to the Soviets that the American people were ready to fight, and, paradoxically, this was necessary to ensure peace.

There's plenty of other Civil Defense films in the Prelinger Archives if you look for them. Overall, I think the science in them is pretty solid, though, again, there's not much you can do if you're standing beneath a bomb

What you have to understand about the civil defense programs is that they were a two-pronged tool.

The first prong is that propaganda you asked about. The United States was at a huge disadvantage against the Soviet Union in a long and drawn out Cold War because the American political system was so much less tolerant of wartime sacrifice than the Soviet one was. Political capital is a resource in war and the Soviets had the upper hand there.

Drills, procedures, and civil defense were a means of protecting that political will. Telling Americans that they could be proactive and take steps to protect themselves from a nuclear exchange made the prospect and thus the American arms race more politically palatable.

The second prong is actual civil defense. Yes, in the event that nuclear weapons were used precious few people, particularly in urban areas, were going to survive. The measures that a person could take in the event of a surprise attack were scant and largely ineffective; you'd have to be miles and miles from the hypocenter to survive.

But someone is going to be miles and miles from the hypocenter. The people who are closer.... there's nothing that can be done for them. Drilling things like "duck and cover" prepared the people at the margins of the bomb's destructive radius to survive and maybe make it to fallout shelters.

Of course, the US couldn't just push those techniques on people in rural areas and tell the city dwellers that they were just going to die. Likewise they couldn't tell people living near air bases, missile silos, and known Soviet targets that none of this stuff matters without giving away their own knowledge of Soviet nuclear planning.

TL;DR: Civil defense is a numbers game that serves both the political and the pragmatic but since you can't just go around telling people that "when the bombs fall you're gonna die" everyone got the training even though many wouldn't benefit from it.

Excellent and interesting posts. Not to quarrel with anything that was said, but I would add from ancient memory that much of the opposition to Civil Defense was based on a fear that military leaders and the president might come to think a nuclear war was an option, or at least that they had to prepare as if for war in order to have a credible deterrent. (The Soviet Union had a massive civil defense program, which was often cited in support of a comparable US program.) There was a similar debate over the continuing development and testing of nuclear weapons, far beyond any conceivable need or possibility of use. The danger of triggering a war by preparing for it is portrayed with a kind of realism in the film Doctor Strangelove, which conveys the mistrust many of us had for the officials who wanted to think about the unthinkable. This is a bit off from the original question, but I think addresses an underlying theme in the responses.

I teach nuclear history in Hiroshima, and while one can claim that things like covering your head with a newspaper did in some small measure offer a thin improvement of protection, every time anyone here sees that the response is somewhere between absurd laughter and tears. As a historian the thing that is so ridiculous about that is the idea that people would have a few seconds between the flash of the detonation and the impact of the blast and heat to do things like get down on the ground, hide behind a wall, or put a newspaper over your head.

The point of the film, as has been mentioned, was to train children to survive a nuclear attack without the assistance of adults, but much of the discussion here misses the point. While a case can be made that there was a need to train children what to do to survive, there are many very powerful subtexts to this film that have nothing to do with survival. One of the most clearly absurd is the notion that within a minute or two of a nuclear detonation the adults would magically return and restore order. I think even second graders understood that this was crazy. But far more than that was the constant repeating, almost mantra-like, that when the bomb explodes there might well be no adults around and that children would have to face this horrid weapon and survive on their own. The film is infused with the message that adult society is unreliable, and that their ultimate product, nuclear weapons, will be something you encounter alone.

Living here in Hiroshima, and having talked to countless survivors who were themselves children when they experienced nuclear attack, the notion that training would lead to orderly action and statistical improvements in survival rates and reductions of injuries is a brutal and nasty joke.

Regardless of how accurate the information is about what does and doesn't aid survival, this focus misses the point entirely. The film was an absolute fiction.