What did ordinary people know about nuclear weapon prior Hiroshima?

[RG]

There is quite rich literature on efforts of allies to construct nuclear bomb and controversies on how far the Germans were. But what ordinary people knew about these efforts? Were they totally surprised and not aware of this what happened on 6th of August or something “was in the air” before?
A few days before I came across a newspaper from 25 February 1945, Dziennik Polski, printed in Kraków. A typical daily newspaper. One of articles was written by Mieczysław Wolfke (http://en.wikipedia.org/wiki/Mieczys%C5%82aw_Wolfke)
And there are presented author’s divagations on possible use of nuclear power. I have no skills to translate it properly but let me quote a few interesting fragments:
During this war we heard several times that in laboratories of our allies there were developed new explosives, many times more powerful than those known before the war. However, explosive energy of these new materials is vanishingly small in comparison to energy which may be achieved thanks to so called “explosion of atoms”.
In 1939, in last months before this war in all bigger research institutes of so called “physics of nucleus”, in Paris, Kopenhagen, Cambridge, in American laboratories and others, there were initialized intensive research over new phenomena, which rightly has been called “explosion of atoms”….
…In the nucleus there is not only the atom’s whole mass but also nearly all resources of internal energy. And this amount is very big. Based on formula derived from Einstein’s theory of relativity we may calculate that one gram of material includes in its atoms about twenty billons kilogram calories. This energy is equal to explosive energy of fourteen thousand tons of nitroglycerine! By breaking the nucleus into its basic elements we release part of this huge energy. Physicists have dreamed for a long time of using these huge amounts of atomic energy, but only the mentioned in the beginning the phenomena of “atomic explosion” gives some opportunities to make these dreams to come true. …
… In 1939 the French physicist Joliot discovered that atoms of uranium and thorium bombarded with neutron rays explode and disintegrate into several fragments. In his further research he proved that explosion of one atom of uranium stimulates explosion of new nucleuses of uranium. It is due to the fact, that number of neutrons, which we use to bombard the uranium atoms, by coming through the layer of tested uranium does not diminish. Rather increases. …
… They have proven also that energy released by explosion of uranium atoms is equal about twenty nine billions of calories per one gram of uranium, which is equal to explosive energy of eighteen thousand tons of nitroglycerine. By discovery of atomic chain reactions, the question of release of atomic energy comes into a phase of practical realization. Only need to arrange appropriate circumstances in this way that once initialized explosion of uranium atoms will further supported and does not finish until complete exhaustion. …
At the end there is a conclusion:

We are sure that the three great Allied Powers will guarantee a long-lasting peace for humanity. In such a case, undoubtedly, such a huge source of energy will be exploited for the sake of progress and development of human culture. Not for destroying it.

Well, I wonder, how much information was given to people in other countries?

[wm]

The answer is all of them, there was no secrets in pure science research before the WW2.

From before the Great War atomic weapons were considered probable. It was known there was a lot of energy in an atom, and it was known the Sun was running on atomic energy, so the energy could be released somehow - the Sun was demonstrating that every day.

Initially it was assumed an explosion could be achieved by rapid radioactive decay ( like in The World Set Free, written in 1913).
Then energy-producing fusion nuclear reactions were discovered in the early thirties, but they were unusable in practice, a reaction would require the extreme pressures and temperatures of the Sun to be started and maintained.
First nuclear chain reactions ( in the room temperature, this time the Sun wasn't needed, making the bomb more probable ) were tested in 1933 - those tests failed because the knowledge was still imperfect and partial.
The discovery describe above was crucial because it was the first practical chain reaction. Now only Mother Nature could have stopped the bomb - by not providing a suitable chain reaction capable element, as most of the known chain reactions are useless - too fast, or too slow. A few years later it was known that she had failed, the elements were found.

[OpanaPointer]

The major participants in WWII had atomic bomb programs, some based on the idea that the enemy might make them. As wm mentioned, talk of the potential of nuclear chain reactions was in the popular literature well before then.

[RG]

Well, the fact that the problem was discussed by professionals is obvious. What I wanted to know, was to what extend information on nuclear weapons was availlable for ordinary people? were there for example cartoons with atomic bombs?

[Erwinn]

I don't think even the General staff knew anything about that, because they planned to drop 5 nukes in Japan's coastline to clear the shores for beachheads.

[wm]

Before the 1939 the information available to both scientists and the general public was more or less the same.
Before the discovery of nuclear fission in 1938 it was speculative writings and science fiction, later it was like shown in that article above. I didn't even noticed it was written in 1945, because I'm quite sure I saw a similar article in the Ilustrowany Kurier Codzienny in 1938/1939.
There was no nuclear scare and no atomic mushrooms, the closest thing was The World Set Free or Krakatit.

But it has to be said the tone of the press and other writings generally were much more subdued and non-aggressive, especially in Poland. It's easy to miss the importance of every important for us today development, including the WW2 reading the pre-war press - despite the fact the information given was detailed and accurate. There was no Ebola/the bomb/anything scary is coming, let's waterboard everyone involved.

[wm]

In April, 1939 the real possibility of the bomb was mentioned in the popular press for the first time - and it wasn't a speculation, but hard science facts backed by famous names.
Any later new discoveries were kept secret, so everything written later including that article in Dziennik Polski was based on this information and the earlier knowledge.

Tempers and temperatures increased visibly today among members of the American Physical Society as they closed their Spring meeting with arguments over the probability of some scientist blowing up a sizable portion of the earth with a tiny bit of uranium, the element which produces radium.

Dr. Niels Bohr of Copenhagen, a colleague of Dr. Albert Einstein at the Institute for Advanced Study, Princeton, N.J., declared that bombardment of a small amount of the pure isotope U235 of uranium with slow neutron particles of atoms would start a “chain reaction” or atomic explosion sufficiently great to blow up a laboratory and the surrounding country for many miles.

Many physicists declared, however, that it would be difficult, if not impossible, to separate Isotope 235 from the more abundant Isotope 238. The Isotope 235 is only 1 per cent of the uranium element.
Dr. L. Onsager of Yale University described, however, a new apparatus in which, according to his calculations, the isotopes of elements can be separated in gaseous form in tubes which are cooled on one side and heated to high temperatures on the other.

Other physicists argued that such a process would be almost prohibitively expensive and that the yield of isotope 235 would be infinitesimally small. Nevertheless, they pointed out that, if Dr. Onsager's process of separation should work, the creation of a nuclear explosion which would wreck as large an area as New York City would be comparatively easy. A single neutron particle, striking the nucleus of a uranium atom, they declared, would be sufficient to set off a chain reaction of millions of other atoms.
The New York Times

[wm]

This:

We are sure that the three great Allied Powers will guarantee a long-lasting peace for humanity. In such a case, undoubtedly, such a huge source of energy will be exploited for the sake of progress and development of human culture. Not for destroying it.

is rather similar to this Francis Aston's remark from 1936:

Personally I think there is no doubt that sub-atomic energy is available all around us, and that one day man will release and control its almost infinite power. We cannot prevent him from doing so and can only hope that he will not use it exclusively in blowing up his next door neighbour.

[wm]

Quite interestingly, in the thirties for the American fans of science fiction nuclear weapons were something obvious and natural.
I was wrong it was the World Set Free/Krakatit only. In literature the US was much more advanced too.

In Uncertainty by John Campbell, written in 1936, atomic bombs are used all the time among others, more powerful weapons:

The three Solarian cruisers were washed in such frightful flame as they had never imagined. Streams of atomic bombs were exploding soundlessly, ineffectively in space, not thirty feet from them as they felt the sudden resistance of the magnetic shields. Hopefully, the 39 probed with her neutron gun. Nothing happened save that several gamma ray bombs went off explosively, and all the atomic bombs in its path exploded at once.

Campbell was a science fiction writer and editor, at that time without any exaggeration the god of sci-fi.

In 1940, written by the famous and influential Robert Heinlein Solution Unsatisfactory introduced the concepts of nuclear arms race, MAD, and second strike capability. The US, frighten by their ramifications , uses a radiological weapon capable of wiping out entire cities, first to kill everyone in Berlin, then to gain total hegemony over the World - for the greater good.

We were searching [...] for a way to use U235 in a controlled explosion. We had a vision of a one-ton bomb that would be a whole air raid in itself single explosion that would flatten an entire industrial center. [. . .] The problem was, strangely enough, to find an explosive which would be enough to blow up only one county time, and stable enough blow up only on request. If we could devise a really practical rocket fuel at the same time, one capable of driving a war rocket at a thousand miles an hour, or more, then w would be in a position to make most anybody say 'uncle' to Uncle Sam.

In Deadline (1943) Cleve Cartmill using freely available information quite accurately described a nuclear weapon, and the problems with its construction, especially the process of isotope separation. Because of that he was investigated by the FBI:

Cleve Cartmill’s “Deadline” provoked astonishment in the lunch table discussions at Los Alamos. It really did describe isotope separation and the bomb itself in detail, and raised as its principal plot pivot the issue the physicists were then debating among themselves: should the Allies use it? To the physicists from many countries clustered in the high mountain strangeness of New Mexico, cut off from their familiar sources of humanist learning, it must have seemed particularly striking that Cartmill described an allied effort, a joint responsibility laid upon many nations.
Discussion of Cartmill’s “Deadline” was significant. The story’s detail was remarkable, its sentiments even more so. Did this rather obscure story hint at what the American public really thought about such a super-weapon, or would think if they only knew?

[OpanaPointer]

There's another story called "Nerves" that was interesting as well. I can look up the author if you wish, it's in a book over yonder somewhere.

[RG]

Thanks, based on your posts it seems, that nuclear wepons were not a total surprise. The other question was the "penetration" of this knowledge in society, but it is rather impossible to asses now.

[OpanaPointer]

Thanks, based on your posts it seems, that nuclear wepons were not a total surprise. The other question was the "penetration" of this knowledge in society, but it is rather impossible to asses now.

You could review Time magazine, that's often a good barometer of the times. The Science section of major newspaper would also be good. As is this. (Hardcopy available at university libraries and major city libraries.)

[wm]

It was reported but, I think the press and the public didn't care much about the subject, the other news were much more interesting at that time.
This is an example from LIFE (April 1939).

To scientists, the experiments is an important step toward finding out what matter is made of and what holds it together. To people who dream of power plants run by atomic energy, physicists reply that these discoveries may mean that a new age of power is 50 years away or just around the corner.

According to Making of the Atomic Bomb a few months earlier the discovery of the process of fission was reported first in Washington Evening Star , then the Associated Press picked it up:

probably the most significant event in the history of physics since the original discovery of radioactivity of uranium and radium.

But for example there was nothing in Popular Mechanics if I'm not mistaken, despite the facts its science section did report a few less important discoveries.
So no sensationalism, but (almost) naked facts, the creation of a nuclear explosion which would wreck as large an area as New York City would be comparatively easy above seems the most dramatic article of of them all.

There's another story called "Nerves" that was interesting as well. I can look up the author if you wish, it's in a book over yonder somewhere.

Nerves (1942) by by Lester del Rey. Some kind of The China Syndrome probably. It would be nice to see what is there, but the problem is the author rewrote the story a few times later, and now the original, first version is hard to come by.

[OpanaPointer]

The version I have is copyrighted 1942.

[Globalization41]

12/16/1943, Catholic Weekly, Atom Bears Witness to God, Energy in Pound of Coal Could Fuel Australia for Months, Part 1

12/16/1943, Catholic Weekly, Atom Bears Witness to God, Energy in Pound of Coal Could Fuel Australia for Months, Part 2

9/7/1944, Cyclotron at Dept. of Terrestrial Magnetism of Carnegie Institute Generates Atom-Smashing Projectiles of 15 Megavolts

10/6/1944, Swedish Correspondent Reports Hitler Has Ordered His Scientists to Speed up Completion of Secret V-3 Atomic Bomb

11/30/1944, Dreams of Releasing Energy in Atoms, Scientists Now Splitting Atoms & Releasing Stores of Energy

Globalization41.