Fission

1
Fission Fusion

• Unit 3
• Chapter 19

2
Climbing out of the Ooze

• The Earth formed out of the solar nebula 4.54
  billion years ago (1).
• All of the matter in the solar nebula came from
  the supernova of a giant mother star

3
It Always Starts With a Bang

• Although the supernova created many elements and
  many isotopes,
• Only 288 isotopes have survived until this day.
• Everything else has decayed.
• Isotopes that have existed since the formation of
  the earth are called Primordial Nuclides.

4
Primitivemaybe

• There are 253 stable primordial nuclides.
• Stable nuclides do not decay (or have not been
  found to decay).
• The remaining 35 are primordial radioactive
  nuclides,
• Whose half-lives are long enough
• And original concentrations high enough
• For them to have survived until now.

5
Stable Stellar

• 80 elements make up stable isotopes,
• Elements 1-82 (not including 43 61)
• Lead is the heaviest stable element.
• Plutonium-244 is the heaviest primordial isotope,
  but so little can be found,
• Uranium is considered to be the heaviest
  naturally occurring element.

6
But, where did they come from?

• Stellar nucleosynthesis
• Stars, like our sun, are mostly hydrogen.
• In the center of a star, hydrogen nuclei are
  fused into helium (Fusion).

7
More Bang For Your Buck!

• In small stars like our sun,
• The heaviest element that can be made from fusion
  is Carbon.
• In bigger stars, the heaviest element that can be
  made is Iron.
• When large stars undergo supernova, the force and
  energy are enough to create many new elements.

8
Thats Ka-blamo!

• All elements heavier than iron (26)
• Were formed during the supernova(s)
• That preceded our solar system.

9
Can I Try?!?

• We can do nucleosynthesis, too!
• New elements are created in
• Special nuclear reactors or
• In particle accelerators.
• As of 2012, all elements up to 118 have been
  claimed to be synthesized.

10
Particle Accelerators

• Sometimes called atom smashers

3 Neutrons
11
Ok, ok, Break it up!

• Fission
• Splitting nucleus into smaller nuclei
• Most fissions are binary
• (produce 2 daughter nuclei)
• A few are ternary
• (producing 3 daughter nuclei)
• Most common mass ratio of binary daughter nuclei
  is 32

12
Just like a cellonly worse!

• Fission can be spontaneous or induced by
  hitting a nucleus with a neutron.
• Often, additional free neutrons are produced!

13
Thisis bad for everyone

• This can lead to runaway fission (chain
  reactions).

Harvard Natural Science
Gahanna, Ohio MS
14
Controlled Fission
15
Break it Down, then Build it Up!

• Fusion
• The combination of atomic nuclei to form larger
  nuclei.
• Fusion of elements lighter than iron release
  energy, while
• Fusion of elements heavier than iron absorb
  energy (opposite of fission).

16
23 4 (1)

• Were really bad at it.
• Fusing deuterium with tritium will produce
  helium-4 and an extra neutron.
• If successful, it would mean practically
  limitless energy!

17
Good Ol Albert E

• When nuclear reactions take place, the total mass
  of the products does not equal the total mass of
  the reactants.
• Any difference is called mass deficit (due to
  binding energy),
• And is accompanied by a corresponding energy
  absorption or release.

18
Mass Deficit

• According to Albert Einsteins equation
• E mc2
• m mass lost or gained in kg
• c speed of light (2.998x108 m/s)
• If mass is lost, the reaction is exothermic
  energy is released.
• If mass is gained, endothermic energy must be
  added.