Neutron cross section according to its neutron cross section and how it reacts to an incident neutron. Nuclides that tend to absorb a neutron and either decay or keep the neutron in its nucleus are neutron absorbers and will have a "capture cross section" for that reaction. Isotopes that fission, are fissionable fuels and have a corresponding "fission cross section". The remaining isotopes will simply scatter the neutron, and have a "scatter cross section". Some isotopes, like uranium-238, have nonzero cross sections of all three. Isotopes which have a large scatter cross section and a low mass are good neutron moderators (see chart
How Many Miles to Babylon? In the 1824 edition of "The Scottish Gallovidian Encyclopedia" there's a description of the rhyme and the game, giving the distance as "six, seven or a lang eight". The rhyme was originally accompanied by a singing game in which two lines face each other, with one player in the middle. At the end of the rhyme the players have to cross the space and any caught help the original player in the middle catch the others. The game seems to have fallen out of use in the twentieth century. In literature In film In music How Many Miles to Babylon?