1. Activities today Bellwork Fission/fusion Discussion
Think-peer share activity: Double-bubble map on Fission-fusion
Note taking
Quiz

2. Fusion vs. fission Nuclear fission:
A large nucleus splits into several small nuclei when impacted by a neutron, and energy is released in this process
Nuclear fusion:
Several small nuclei fuse together and release energy. 2

3. A little bit on the atom…
Neutral neutrons -
Nucleus - - - -    - - -
Negative electrons
Positive protons

4. Conservation of Energy/Mass
Energy cannot be created or destroyed – it can only change form.
E = mc2
Mass is really a form of energy

5. Another look at E = mc2 E = energy (J) m = mass (kg)
c = speed of light (3 x 108 m/s)
Mass is really just another form of energy!

6. FUSION AND FISSION

7. THE SUN
Every second, the sun converts 500 million metric tons of hydrogen to helium. Due to the process of fusion, 5 million metric tons of excess material is converted into energy in each second. This means that every year, 157,680,000,000,000 metric tons are converted into energy.

8. Nuclear Fusion
Nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus.
It is accompanied by the release or absorption of energy depending on the masses of the nuclei involved..

9. FUSION
DEUTERIUM
NEUTRON
HELIUM
TRITIUM

10. Complete the Reaction 4Be 1H element 4Be 2He 6C 2He 2He 6C 8O 2He
atomic number (protons)
4Be 1H
2He 6C
2He 1H 1H 6C
2He
4Be 8O
2He
2He

11. Fusion Changes Mass to Energy E=mc2
.993 kg Helium He H
1kg Hydrogen

12. Learning Check What process creates energy in the Sun?
Fusion of hydrogen into helium in the Sun’s core generates the Sun’s energy.
How long ago did fusion generate the energy we now receive as sunlight?
Fusion created the energy we receive today about a million years ago. This is the time it takes for photons and then convection to transport energy through the solar interior to the photosphere. Once sunlight emerges from the photosphere, it takes only about 8 minutes to reach Earth.

13. Learning Check

14. NUCLEAR FISSION
A reaction in which an atomic nucleus of a radioactive element splits by bombardment from an external source, with simultaneous release of large amounts of energy, used for electric power generation

15. Nuclear Fission Neutron induced in U235 Fission is Exothermic
The sum of the masses of
the resulting nuclei is less
than the original mass (about 0.1% less)
The “missing mass” is converted to energy according to E=mc2

16. Neutrons may:
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

17. How fusion can be used? GOOD EVIL
A controlled reaction in a reactor used to produce cleaner, inexpensive electricity???
EVIL
A fission bomb starts a fusion chain reaction to create an incredibly powerful weapon – thermonuclear weapons (H-bombs), MUCH more destructive than atomic bombs.

18. A-bomb vs. H-bomb Atomic bomb (Hiroshima)– fission process
Killed over 66,000 people instantly
13 kilotons of TNT-equivalent
2 exploded in warfare
Hydrogen bomb – fusion process
10 megatons (million-tons) of TNT-equivalent
NEVER exploded in warfare
Is it the bomb too big to ever be used???

19. U.S. Electrical Power Production by Source
The United States has 103 nuclear power reactors in 31 states.
Nuclear energy provides electricity for one of every five homes and business … the second-largest source of electricity after coal.
Some states are clearly are more dependent on nuclear energy than others. Vermont gets 76 percent of its electricity from nuclear reactors … New Hampshire, 58 percent … and South Carolina, 55 percent.
In Virginia, nuclear power provides more than 40 percent of the electricity used.
Source: EIA
(2004)

20. Nuclear Fuel Costs Nuclear Fuel Costs Include
Uranium
Enrichment
Manufacturing
Waste Disposal
Total Nuclear Fuel Cost is Only About 0.5 cents per kilowatt-hour
Uranium accounts for only about 20% of this cost or 0.1 cents per kilowatt-hour
Increasing Uranium Cost has Minimal Impact

21. Review Nuclear fission:
A large nucleus splits into several small nuclei when impacted by a neutron, and energy is released in this process
Nuclear fusion:
Several small nuclei fuse together and release energy.

22. Fiss vs. Fuse Fiss = break down
Start with a larger atom and finish with two or more smaller atoms
Fuse = build up
Start with two smaller atoms and finish with one larger atom

23. 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

24. Mini-assessment
1. Which nuclear process produces large amounts of energy?
A. Fission
B. Fusion
C. Both fission & fusion
D. Neither fission nor fusion

25. Mini-assessment
2. Fission is the process that _________ atomic nuclei.
A. Combines
B. Burns up
C. Stores
D. Splits

26. Mini-assessment
3. Mass may be converted into energy.
A. True
B. False

27. Mini-assessment 4. The fission process requires heavy atomic nuclei.
A. True
B. False

28. Mini-assessment
5. Name a nuclear reaction that occurs within the sun:

29. Mini-assessment
6. Fission is a natural process that occurs on the planet Earth.
A. True
B. False

30. Mini-assessment
7. Explain this equation: (4 points)
E = mc2

31. 8. Draw a Double Bubble Map of Fusion and Fission
Differences Similarities Differences

33. Cookie Fusion Procedure Cut 2 squares of wax paper 10 cm on a side
Cut 5 cm wide slice of cookie dough (atom)
Find the mass of the atom and record on the table
Place the atom one cm away from the edge of a wax paper square
Repeat step 2 thru 4 for a second atom
Place the atoms about 2 cm from each other
Place both atoms on a plate and microwave for 1 minute
Remove the “new element” and let cool for 2 minutes
Find the mass of the “new element”
Complete the table

34. Cookie Fusion Mass Before Cooking Mass After Cooking Atom 1 Atom 2
Total
Difference