1. “The World We Create” NATS 101 Section 6 New Homework Posted in D2L. Due on Tuesday at 2 PM. 01/28

2. UNIT 1: Energy Sources, Conventional or Alternative? Nuclear Energy

3.  Why do some countries use more nuclear energy than others? Central Questions  What is the difference between producing chemical energy and nuclear energy?  What do we mean by ionizing radiation?  How can we detect the presence of ionizing radiation in our surroundings?

4. Limited Sources The earth’s reserves of fossil fuels are limited: 2007 20202030 2040 20502300 Gas begins to run out Oil begins to run out Coal begins to run out Because of this we need to:  Conserve;  Improve efficiency;  Develop new chemical fuels;  Search for alternative sources of energy.

5. United States vs. France ELECTRICITY PRODUCTION US FRANCE

6. Country# Nuclear Power Plants % Electricity from Nuclear Power U.S. >10021 France 5675 Japan 4026 UK 3720 Sweden 1246 Nuclear Energy Output Different Countries

7. Different Choices What factors may have influenced these countries’ choices? (political, economical, social, environmental, historical, etc.) Are you for or against the use of Nuclear Energy? Why? You have 3-4 minutes

8. Why are we afraid of Nuclear Energy? Two different types of processes: Chemical Reactions Nuclear Reactions  Atoms only rearranged  Mass is not “lost”  Energy is produced C(s) + O 2 (g)  CO 2 (g) 235 92 U + 1 0 n  141 56 Ba + 92 36 Kr + 3 1 0 n  New atoms form  Mass is “lost”  Vast amounts of energy is produced

9. Atomic Structure Atoms of the same element have the number of protons in the nucleus (Atomic Number) Atoms of the same element that differ in the number of neutrons are called ISOTOPES (they have different mass number) (Number of protons) (Number of protons plus neutrons)

10. Nuclear Fission 235 92 U + 1 0 n  141 56 Ba + 92 36 Kr + 3 n 1 0 + energy A small amount of mass is transformed into a huge amount of energy. E = mc 2 We have developed strategies to split atomic nuclei apart (fission). Neutron bombardment Some mass is lost in the process!

11. Let’s Calculate If you induce the fission of 1.0 g of Uranium you get 90,000,000,000,000 = 9.0 x 10 13 J During the nuclear fission of Uranium, 0.1% of the mass is transformed into energy. E = mc 2 C= 300,000,000 m/s Equivalent to the energy  Released by 33,000 tons of TNT  Needed to raise 700,000 cars 6 miles into the sky  Turn 8.7 million gallons of water into steam

12. Radiation Most of the energy generated during a nuclear process is released in the form of RADIATION. Radiation is energy in the form of waves or particles sent out over a distance. Microwave radiation Ultraviolet light X-rays Infrared radiation Visible light

13. Matter Interactions Different types of radiation interact differently with matter. You have 8 minutes Make a drawing that models what you think happens when each type of radiation interacts with molecules or atoms in your body. Microwave radiation Ultraviolet light X-rays Infrared radiation Visible light

14. Non-Ionizing Radiation: Low energy levels: Strong enough to influence the atoms or molecules it contacts (translation, rotation, vibration), but not strong enough to affect their structure. Ionizing Radiation: Higher energy levels: It has enough energy to affect the structure of the atoms. Particularly, to remove electrons (ionize). Radiation

16. Radioactivity Some substances, such as uranium and plutonium, emit ionizing radiation spontaneously (you don’t need to split them). This property is called Radioactivity Radioactivity results from changes in the atomic nuclei of the atoms How do we detect and measure it?

17. Geiger Counter The Geiger Counter measures the number of ionizing events per unit of time (counts per minute or CPM). (+) How would you design/build an instrument like this?

18. Radioactive Stuff Let’s measure the radioactivity of several objects and substances using a “Geiger Counter.” Why are they radioactive?