1. Wilhelm Rontgen 1895 German Scientist Playing with a Crookes tube
Sitting in a dark lab, tube covered with black paper, held up a book to the tube . . .
Image of key appeared on paper painted with Barium across the room
The key had been a bookmark
Wilhelm Rontgen

2. Rontgen’s Lab Rontgen thought he was hallucinating Told no one
Shut himself in the dark lab for seven weeks
Held up a metal plug and saw … his BONES

3. “Black Magic”
Took a picture of wife’s hand (afraid, she never went back to the lab)
Showed that these images were real
Rontgen began to document and rationalize his work w/ physics knowledge of the time

4. The Nobel Prize in Physics 1901 Wilhelm Conrad Röntgen
Namesake Element:
Rontegenium
Atomic #
Atomic Weight
Discovered in 1994, Germany
Highly Radioactive, but this element does not emit x-rays

5. FUSION AND FISSION

6. First, a little bit about energy

7. Forms of Energy Heat Chemical Electromagnetic Nuclear Mechanical
The five main forms of energy are:
Heat
Chemical
Electromagnetic
Nuclear
Mechanical

8. Heat Energy
The internal motion of the atoms is called heat energy, because moving particles produce heat.
Heat energy can be produced by friction.
Heat energy causes changes in temperature and phase of any form of matter.

9. Chemical Energy Making and Breaking bonds
Chemical Energy is required to bond atoms together.
And when bonds are broken, energy is released.

10. Chemical Energy
Fuel and food are forms of stored chemical energy.

11. Electromagnetic Energy
Power lines carry electromagnetic energy into your home in the form of electricity.

12. Electromagnetic Energy
Light is a form of electromagnetic energy.
Each color of light (Roy G Bv) represents a different amount of electromagnetic energy.
Electromagnetic Energy is also carried by X-rays, radio waves, and laser light.

13. Mechanical
Kinetic /Potential

14. Nuclear Energy The nucleus of an atom is the source of nuclear energy.
Energy holding nucleus together

15. Nuclear Energy Nuclear Energy is the most concentrated form of energy!
2 major reactions :Fission & Fusion

16. Result: gain or loss of energy
Fusion
Nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus.
The fusion of two nuclei lighter than iron or nickel generally releases energy.
The fusion of nuclei heavier than them absorbs energy.
Result: gain or loss of energy

17. Nuclear Fusion

18. Nuclear Fusion Example
The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.

19. NUCLEAR FISSION
Fission may be defined as the process of splitting an atomic nucleus into fission fragments
The fission fragments are generally in the form of smaller atomic nuclei and neutrons
Large amounts of energy are produced by the fission process

20. More about fission
Fissile nuclei are generally heavy atoms with large numbers of nucleons
The nuclei of such heavy atoms are struck by neutrons initiating the fission process
Fission occurs due to electrostatic repulsion created by large numbers of protons within the nuclei of heavy atoms

21. Nuclear Fission
Neutron induced in U235

22. Neutrons may: Creates two smaller nuclides and free neutrons
1 - Cause another fission by colliding with a U235 nucleus
2 - Be absorbed in other material
3 - Lost in the system
If sufficient neutrons are present, we may achieve a chain reaction
Creates two smaller nuclides and free neutrons
The free neutrons potentially collide with nearby U235 nuclei
May cause the nuclide to split as well
Each split (fission) is accompanied by a large quantity of E-N-E-R-G-Y

23. Fission Example

24. Where does the energy come from?
We often say that matter cannot be created nor destroyed. However . . .
Einstein taught us that Energy and matter are different forms of the same thing!
E = mc2

25. Mass Defect The nucleus
is composed of protons and neutrons
the actual mass is less than the mass of the separate particles.
The "missing" mass is in the form of energy holding the nucleus together.
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26. Uranium-238 238U nucleons The nuclear mass (protons & neutrons)
of uranium-238 is
amu
238U 92
atomic number
(protons)
A proton is amu
A neutron is amu
What mass is expected
for the nucleus of 238U?
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27. Uranium-238 92 protons (92)(1.00728) = 92.6698 146 neutrons
(92)( ) =
146 neutrons
(146)( ) =
predicted mass =
actual mass =
mass defect = amu
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28. Masses of Atoms The nuclear mass of 238U is 238.0003
Why does the Handbook of Chemistry and Physics
list the mass of uranium­238 as ?
(92)( ) =
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29. Binding Energy
The mass defect indicates the total energy involved in holding the nucleus together.
To determine the stability of the nucleus, the binding energy per nuclear particle is a better measure.
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30. Binding Energy of 238U
actual mass
predicted mass
amu
DE = Dmc2 = MeV/amu
What is the binding energy per nucleon of 238U?

31. Binding Energy of 238U Binding energy per nucleon =
( amu)(931.5 MeV/amu)
238 nucleons =
7.57 MeV
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32. Binding Energy The nuclei with the greatest binding energy per nucleon
62Ni
The nuclei with the greatest
binding energy per nucleon
are the most stable.
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33. E = mc2 Matter can be changed into energy In the equation above:
E = energy
m = mass
c = speed of light
Small amount of mass becomes a HUGE amount of energy

34. Chemical Reactions Nuclear Reactions
Involve changes in electrons
Acids & Bases, combustion, displacement
The same atoms appear on both sides of the reaction.
Follows Dalton’s Law of Conservation of Mass
Small amount of energy generated
Burning fossil fuels
Nuclear Reactions
Involve changes in the nucleus
Nuclear fusion, nuclear fission
New atoms appear as products of the reaction.
Breaks Dalton’s Law of Conservation of Mass
Large amount of energy generated
1 million times more than chemical reactions
Nuclear fusion on the sun
Nuclear fission for reactors

35. Decay vs. Nuclear Reactions
Alpha, beta, and gamma decay occur as ONE atom tries to increase it’s stability by getting rid of a few neutrons, or protons & neutrons.
The product is an alpha, beta, or gamma particle and ONE new atom. There is only ONE thing on the left hand side.
Nuclear reactions involve more than just getting rid of a few protons or neutrons. The new atoms produced are VERY different elements than the reactant.
Nuclear reactions must be started, so there are 2 things on the left hand side.
Nuclear fission: makes 2 or more much smaller atoms
Nuclear fusion: makes 1 much larger atom

36. What are the differences between the 2 above nuclear equations??
Nuclear Fission
Alpha Decay
What are the differences between the 2 above nuclear equations??

37. Review
Mass and Energy are two forms of the same thing; neither can be created nor destroyed but mass can be converted into energy (E = mc2)
Fission is a nuclear reaction in which a heavy atomic nucleus is split into lighter atomic nuclei
Fusion is a nuclear reaction in which 2 light atomic nuclei are combined into a single, heavier atomic nucleus

38. Quiz Which nuclear process produces large amounts of energy?
A. Fission
B. Fusion
C. Both fission & fusion
D. Neither fission nor fusion

39. Quiz Fission is the process that _________ atomic nuclei. A. Combines
B. Burns up
C. Stores
D. Splits

40. Quiz
Mass may be converted into energy.
A. True
B. False

41. Quiz The fission process requires heavy atomic nuclei. A. True
B. False

42. Quiz
Name a nuclear reaction that occurs within the sun:

43. Bonus
Explain this equation:
E = mc2