The document discusses nuclear fission and fusion, highlighting key discoveries and reactions, including James Chadwick's identification of the neutron and the resulting experiments by scientists like Enrico Fermi which led to the understanding of fission in uranium. Fission produces significant energy used for electricity generation and in nuclear weapons, while fusion, which occurs in stars, has potential for cleaner energy but currently lacks practical reactors. Both processes present challenges related to radioactive waste and safety in weapon applications.

1. Nuclear Fission and Fusion
TEKS Par 112.35 #12c

2. Discovery of Fission
 James Chadwick discovered the neutral particle in
the nucleus of the atom in 1932.
 He called it a “neutron.”
 Many scientists then started experimenting with
neutrons.
 Enrico Fermi and his team bombarded every
known element with neutrons, and found among
the products some new, radioactive elements.
 Neutrons had caused fission, or breakup, of nuclei

3. Fission of Uranium
 Uranium produced lighter but radioactive
products when bombarded with neutrons.
 Fermi discovered that neutrons could be slowed
down by first funneling them through light
elements like carbon.
 Ida Noddack, Otto Hahn and Lise Meitner
showed that uranium was fissioning into barium
and other lighter, radioactive elements.
 Later, U-235 and Pu-239 were shown to be the
best candidates for fission with slow neutrons.

4. Fission Reaction
 U-235 fissions like this:
Visionlearning.com
Nuclearenergyissafe.com
The products of fission are
unpredictable and radioactive

5. Nuclear Energy
 Because matter is converted
into energy in nuclear
reactions, fission produces a
great deal of heat
 When controlled, this can be
used to drive turbines that
produce electricity, as in the
South Texas Nuclear Project.
Window.state.tx.us

6. Nuclear Energy
 Because matter is converted
into energy in nuclear
reactions, fission produces a
great deal of heat
 When released from a
carefully engineered nuclear
weapon, this energy can do
an incredible amount of
damage, as when the U.S.
dropped bombs on Japan to
end WW2.
Nuclear-news.net

7. Nuclear Fission
 Nuclear fission occurs when two light elements
are forced together to make a heavier one.
 The two nuclei FUSE into a new one.
 This releases a great deal of energy.
 Here is a typical reaction equation:
H-3 + H-2 → He-4 + n + energy

8. Uses of Fusion
 Nuclear fusion occurs in the sun and other stars,
and so it gives us all the energy used on earth in
photosynthesis.
Gosunstove.com
So if your house
has solar cells,
fusion is the
ultimate source
of the electricity.

9. Uses of Fusion
 Nuclear fusion is the
driving force behind
thermonuclear weapons.
 They are no longer
tested in the
atmosphere. They had
released much harmful
radioactive isotopes in
the 1950s.
en.wikipedia.org

10. Electricity from fusion?
 Nuclear fusion would use a cheap fuel—hydrogen
from water.
 It would generate less nuclear waste.
 Research into fusion reactors has been going on
since the 1940s.
 There is no working fusion reactor yet.

11. Summary
Nuclear Reactions
Type What
Happens
By-products
Energy
Uses
Waste
Problems
?
Fission U-235 or
Pu-239
splits
Radio-active
isotopes
Electric
Power/
weapons
Where to
store the
radioactive
waste?
Terrorism.
Fusion H nuclei
forced
together
Neutrons
Small
elements
Sun &
stars/
weapons
If weapons
are used,
uncontrolled
radiowaste