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DerKezzer (December 31, 1969 at 4:59 pm)
***cont.***
Fusion of light nuclei releases even more energy but first requires high temperatures, for the enormous repulsive forces between the protons (which are to be fused) have to be overcome. When 2 protons fuse, one thows out a positron - which is the positively charged counterpart of an electron - and becomes a neutron. The result is still hydrogen, namely heavy hydrogen alias deuterium (1p., 1 n.).
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***cont.***
There is some critical mass above which the neutron loss ceases to stop the chain reaction. If an overcritical mass of the apt material is put and pressed together long enough, e.g. by a conventional explosive, it reaches temperatures of over 10 million degrees centigrade and an enormous pressure which makes an extreme flash, a quickly expanding fireball and a great blast. It also releases much radioactive fallout from the non-split material and the fission products.
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
Whereas a U-238 (238-92=146 neutrons) nucleus takes fast neutrons to be split, the lighter but more unstable U-235 nucleus can be split by normally slow ('thermal') neutrons. The fisson releases - additionally to the energy - three further neutrons which can split further U-235 nuclei. if there is too little U-235, this process stops because ever more neutrons leave the material through it's surface. This effect decreases with the mass U-235 packed together.
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
Building nuclei with more than 26 protons (so beyond iron) also takes energy, and this is why such elements like gold (79 protons) or even uranium (92 p.) only arise by supernovae which are exploding heavy (at least 1.4 times the sun) stars at the end of their 'life'.
They exist on earth because all the solar system is built of the debris of a former supernova or several.
Some nuclids are especially apt to be split in a chain reaction, like U-235.
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
Due to the fact that nuclear reactions release much more energy than chemical ones, nuclear weapons have vastely more explosive power than conventional bombs.
The released energy is binding energy; for the forces are attractive, it's negative. This means it TAKES energy to separate the nucleons a nucleus is built of.
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
Because all the forces within the atomic nucleus are much stronger than those within the shell, all nuclear reaction release (or take) much more energy per atom than normal chemical reactions. This is particularly true for nuclear fission of heavy nuclei (such like uranium (92 protons) or plutonium (94 protons)) and even more for the fusion of light nuclei. The lightest and simplest nucleus is that of normal hydrogen which is simply a proton.
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
The form in which extra energy is released during an alpha or beta decay is called gamma radiation, and this is nothing else than "light" but which extremely short waves (shorter than even x-rays whith which they are closely related). It's also dangerous because it can also destroy biological structures, causing cancer, damaging embryos and, in high doses, cause the radiation sickness.
***t.b.c.***
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
Other, particularly heavy nuclei (=atomic cores) throw out an alpha particle which is built of 2 protons and 2 neutrons, being nothing else than a normal helium nucleus which is also rather fast but soon (after millimeters in matter) braked down to small velocities, ripping 2 electrons from other atoms or molecules (this makes itextremely dangerous to swallow or breathe in alpha radiators). In both cases (alpha and beta radiation), extra energy is often released.
***t.b.c.***
atomicdonutinc (December 31, 1969 at 4:59 pm)
dont you know we only used two bombs on the enemy? the rest were all practice, so i dowt were going to nuke something soon, with the risk of nuclear warfare
DerKezzer (December 31, 1969 at 4:59 pm)
***continuation***
There are also nuclei with an EQUAL entire number of nucleons but DIFFERENT fractions of protons and neutrons, e.g.: N-14 with 7 protons and 7 neutrons vs. C-14 with 6 protons and 8 neutrons; the latter is radioactive and "decays" to the former, throwing out a very fast electron which is then called a beta particle. This normally happens to nuclei with "too many" neutrons.
***t.b.c.*** |
