Fission: The nucleus splits either by radioactive decay or because it has been bombarded by other subatomic particles called neutrinos. The results of this is that you have less combined mass than the original nucleus and the missing mass is converted into nuclear energy. (What is Fission?)
Fusion: The reaction where two lighter atoms join to form a heavier one (What is Fusion?). The total mass resulting from the fused nucleus, is a little bit different than that of its initial components separate masses. The difference is then released as energy.
Nuclear energy or nuclear weapons relate to fission and fusion because in fission, energy is gained by splitting apart heavy atoms (uranium), into smaller atoms (such as iodine, caesium, strontium, xenon and barium, to name just a few) whereas fusion is combining light atoms, (in current experiments two isotopes of hydrogen, deuterium and tritium), which forms a heavier one (helium). Fission is triggered by uranium absorbing a neutron, which renders the nucleus unstable andthis chain reaction is the key to fission reactions, but it can lead to a runaway process, as in a nuclear bomb. (By setting up magnetic field lines toroidally around the interior of the tokamak, the ions and electrons in […], "How do fission and fusion reactions compare? | EUROfusion")
Fusion: The reaction where two lighter atoms join to form a heavier one (What is Fusion?). The total mass resulting from the fused nucleus, is a little bit different than that of its initial components separate masses. The difference is then released as energy.
Nuclear energy or nuclear weapons relate to fission and fusion because in fission, energy is gained by splitting apart heavy atoms (uranium), into smaller atoms (such as iodine, caesium, strontium, xenon and barium, to name just a few) whereas fusion is combining light atoms, (in current experiments two isotopes of hydrogen, deuterium and tritium), which forms a heavier one (helium). Fission is triggered by uranium absorbing a neutron, which renders the nucleus unstable andthis chain reaction is the key to fission reactions, but it can lead to a runaway process, as in a nuclear bomb. (By setting up magnetic field lines toroidally around the interior of the tokamak, the ions and electrons in […], "How do fission and fusion reactions compare? | EUROfusion")