fission

Examples of fission in the following topics:

• Nuclear Fission

  • Nuclear fission is a process by which the nucleus of an atom is split into two or more smaller nuclei, known as fission products.
  • Most fissions are binary fissions that produce two charged fragments.
  • These nuclei are called unstable, and this instability can result in radiation and fission.
  • In order to initiate fission, a high-energy neutron is directed towards a nucleus, such as 235U.
  • While nuclear fission can occur without this neutron bombardment, in what would be termed spontaneous fission, this is a rare occurrence; most fission reactions, especially those utilized for energy and weaponry, occur via neutron bombardment.

• The Hydrogen Bomb

  • The hydrogen bomb is a nuclear weapon that uses a mixture of fission and fusion to produce a massive explosion.
  • The only two nuclear weapons that have been used were both fission-based.
  • The nuclear fusion releases neutrons much faster than a fission reaction, and these neutrons then bombard the remaining fissile fuel, causing it to undergo fission much more rapidly.
  • Radiation from a primary fission bomb compresses a secondary section containing both fission and fusion fuel.
  • The compressed secondary is heated from within by a second fission explosion.

• Nuclear Fission in Reactors

  • Nuclear reactors convert the thermal energy released from nuclear fission into electricity.
  • Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller (lighter) nuclei.
  • The kinetic energy of fission products is converted to thermal energy when these nuclei collide with nearby atoms.
  • The power output of the reactor is adjusted by controlling how many neutrons are able to create more fissions.
  • An induced nuclear fission event.

• Binary Fission

  • Binary fission is the method by which prokaryotes produce new individuals that are genetically identical to the parent organism.
  • Prokaryotes, such as bacteria, propagate by binary fission.
  • Due to the relative simplicity of the prokaryotes, the cell division process, or binary fission, is a less complicated and much more rapid process than cell division in eukaryotes.

• The Atomic Bomb

  • Atomic bombs are nuclear weapons that use the energetic output of nuclear fission to produce massive explosions.
  • Atomic bombs are nuclear weapons that use the energetic output of nuclear fission to produce massive explosions.
  • These bombs are in contrast to hydrogen bombs, which use both fission and fusion to power their greater explosive potential.
  • On August 6th, 1945, a uranium gun-type fission bomb code-named "Little Boy" was detonated over the Japanese city of Hiroshima.
  • Fission can be self-sustaining because it produces more neutrons with the speed required to cause new fissions.

• Conservation of Nucleon Number and Other Laws

  • Through radioactive decay, nuclear fusion and nuclear fission, the number of nucleons (sum of protons and neutrons) is always held constant.
  • Chain reactions of nuclear fission release a tremendous amount of energy, but follow the Law of Conservation of Nucleon Number.
  • This is the same with all fission reactions.
  • Thus, the number of nucleons before and after fission and fusion is always constant.
  • If U-235 is bombarded with a neutron (light blue small circe), the resulting U-236 produced is unstable and undergoes fission.

• Nuclear Reactors

  • The energy released from nuclear fission can be harnessed to make electricity with a nuclear reactor.
  • When a large, fissile atomic nucleus such as uranium-235 or plutonium-239 absorbs a neutron, it may undergo nuclear fission.
  • This chain reaction can be controlled using neutron poisons and neutron moderators to change the portion of neutrons that can cause more fissions.
  • Nuclear reactors generally have automatic and manual systems to shut the fission reaction down if unsafe conditions are detected.
  • A possible nuclear fission chain reaction.

• Prokaryotic Reproduction

  • Prokaryotes reproduce asexually by binary fission; they can also exchange genetic material by transformation, transduction, and conjugation.
  • Reproduction in prokaryotes is asexual and usually takes place by binary fission.
  • Binary fission does not provide an opportunity for genetic recombination or genetic diversity, but prokaryotes can share genes by three other mechanisms .
  • Besides binary fission, there are three other mechanisms by which prokaryotes can exchange DNA.

• Nuclear Weapons

  • A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions—either fission, fusion, or a combination.
  • A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion.
  • The first fission (i.e., "atomic") bomb test released the same amount of energy as approximately 20,000 tons of trinitrotoluene (TNT).
  • On August 6, 1945, a uranium gun-type fission bomb code-named "Little Boy" was detonated over the Japanese city of Hiroshima.
  • Only three days later a plutonium implosion-type fission bomb code-named "Fat Man" (as illustrated in ) was exploded over Nagasaki, Japan.

• Types of Sexual and Asexual Reproduction

  • Animals may reproduce asexually through fission, budding, fragmentation, or parthenogenesis.
  • Fission, also called binary fission, occurs in prokaryotic microorganisms and in some invertebrate, multi-celled organisms.
  • Some unicellular eukaryotic organisms undergo binary fission by mitosis.
  • Some sea anemones and some coral polyps also reproduce through fission .
  • Coral polyps reproduce asexually by fission, where an organism splits into two separate organisms.