The product is an abstraction, not necessarily related to the real world as we know it. It was a dramatic moment but Dr. Fermi and the others watching intently knew that it would work. In l939 Han and Strassman observed that barium was present in the residue of experiments in which uranium was bombarded with neutrons. Meitner attempted mathematical analysis of these experiments and found that the total of the atomic masses of the residual elements was less than the atomic mass of uranium. All that remained was precise calculations and trial of the experiment, but they knew it would work, they had made it all up.
Science is the belief in the ignorance of experts.
Furthermore, the Indians observed that the tenderness decreased steadily as the meat was boiled at locations farther and farther up the mountain. So they invented an explanation which was that evil spirits prevent meat from cooking and the density of evil spirits increases as altitude increases. This was a plausible and probably useful explanations. This would keep out evil spirits and the meat should be well done. There are less air particles atop the mountain, so there is less air pressure pushing on the surface of the water.