1. APES Unit 3 – Energy Lesson 2 – Energy Types, Math Problems & Nuclear Decay

2. Practice Questions 1.The capacity to do work is called ____. a. kinetic energyb. potential energy c. mechanical energyd. energy 2. The best definition of heat is ____. a. potential energyb. temperature c. transfer of energyd. kinetic energy

3. Practice Questions 3. The conclusion that it is impossible to completely convert heat into work without making other changes in the universe is ___. a. the first law of thermodynamics b. the second law of thermodynamics 2. A Watt is ____. a. 1 s/Jb. 1 J/s c. 1 cal/s d. 1 s/cal

4. Practice Questions 5. A car ad claims there is a new mechanical part of the engine that allows for 100% recovery of the energy used during burning gasoline. You should be skeptical of such claims because they violate the ___. a. first law of thermodynamics b. second law of thermodynamics c. law of conservation of matter d. activation energy for all chemical reactions

5. Unit 3 Lesson 2 Learning Targets Explain how NPP determines the ecosystem’s capacity Identify differences between renewable and nonrenewable energy Convert typical energy problems from Watts to kWh, BTUs, calculate cost, efficiency, etc. Pros and cons of Nuclear energy Radioactivity types and radioactive decay Half life activity

6. Math Problems 3. How much energy does it use in 12 hours of operation? a)12 h 3600 s 100 J = 4,320,000 J = 4.32 x 10 6 J 1 h 1 s b) How much energy does the bulb convert to light during the 12 hours? (4.32 x 10 6 J)(0.2) = 864,000 J of light

7. Math Problems 3. Convert total energy use to kWh c) 4.32 x 10 6 J 1 kWh = 1.2 kWh 3.6 x 10 6 J

8. Math Problems 4. Find the energy used in J and kWh. a) 4000 W = 4000 J/s 4000 J 1 hr 5 loads 4 wks 3600 s = 1 s 1 load 1 wk 1 hr = 288,000,000 J = 2.88 x 10 8 J 2.88 x 10 8 J 1 kWh = 80 kWh 3,600,000 J

9. Math Problems 4. Find the operating cost for 4 wks. b)Assume the cost is $0.758/kWh $0.0758 80 kWh = $6.06 kWh

10. Math Problems 5.How many kcal/yr does each type of refrigerator use? 1 kWh = 860 kcal SINGLE DOOR 600 kWh 860 kcal = 516,000 kcal/yr yr 1 kWh DOUBLE DOOR 1880 kWh 860 kcal = 1,616,800 kcal/yr yr 1 kWh

11. Math Problems 6. a. Total number of kWh per year 7.25 kWh 137 days 24 hrs = 23,838 kWh/yr 1 hr 1 year 1 day b. Cost of AC for 1 yr 23,838 kWh $0.0825 = $1966.64/yr 1 yr 1 kWh

12. Math Problems 6. c. kcal used per year 23,838 kWh 860 kcal = 20,500,680 kcal/yr 1 kWh d. How many BTUs used in 1 yr? 23,838 kWh 3400 BTU = 81,049,200 BTUs/yr 1 yr 1 kWh

13. Do # 7 & 8 for homework Save #9 for a warm up activity another day

14. Math Problems 7. a. how many kWh per year does this represent? 400 J 4 hr 3600 s 365 days 1 kWh = s 1 day 1 hr 1 yr 3.6 x 10 6 J = 2.10 x 109 kWh = 584 kWh/yr 3.6 x 10 6 yr

15. Math Problems 7.b. if fluorescent bulb saves 60W per night, what savings in kWh does this represent in 1 yr? 400W – 60 W = 340 W = 340 J/s 340 J 4 hr 3600 s 365 days 1 kWh = s 1 day 1hr 1 yr 3.6 x 10 6 J = 4.96 kWh/yr

16. Math Problems 7.C. If bulb costs $18 but lasts 10 yrs, wise investment? Why? $0.0825 (584 – 496.4 kWh) = $0.0825 87.6 1 kWh = $7.23 / year, so bulb will pay for itself in ~2.5 years ($7.23 x 2 years = 14.56; $7.23 x 3 yrs = 21.79)

17. Math Problems 8.Gallons of gas used in 1 yr 5 trips 7.5 mi 1 gal 52 wks = 1950 gal 1 wk 1 trip 22 mi 1 yr 22 yr = 88.64 gal/yr b. Gallons to kcal/yr if there are 32000 kcal/gal 88.64 gal 32000 kcal = 2,836,363.64 kcal/yr 1 yr 1 gal

18. Math Problems 8.c. other energy uses, other than transportation Processing, harvesting, maintaining conditions for livestock... d.Help save energy by… Eating fewer processed foods, eat less meat, eat locally grown food

19. Scale of Global Energy Is Enormous Drives 500,000 cars; using over 500,000 gallons of petroleum every day OECD population equals 1,200 such cities today -Growing to almost 1,300 by 2030 Consumes over 1,000 gallons of oil per minuteRequires two dedicated, world-scale power plantsNeeds 6 Million BTUs of energy every secondUses 150 tons of coal each hour On average, an city of 1 million people: Today the world uses 15 billion BTUs of energy every second

20. Developed nations consume lots of energy Developing nations use manual or animal energy instead of fossil fuels Developed Transportation Industry Other Developing Subsistence Activities (agriculture, food preparation, home heating)

21. 2005 – 2030 Growing Global Demand By Sector Quadrillion BTUs 2005 2030 Transportation Industrial Res/Comm PowerGen Energy Savings

22. With this much demand, what sources are there to meet the need? Renewable vs. Non-renewable Energy Sources

23. Renewable & Nonrenewable Resources Renewable energy = supplies of energy will not be depleted by our use – Ex. Sunlight, geothermal energy, and tidal energy Nonrenewable energy at our current rates of consumption we will use up Earth’s accessible store of these sources in a matter of decades to centuries – Oil, coal, natural gas, nuclear energy – To replenish the fossil fuels we have depleted so far would take millions of years

24. Renewable vs. Nonrenewable Energy

25. Fossil fuels are created from fossils Fossil fuels we burn today were formed from the tissues of organisms that lived 100-500 million years ago Came from organic material is broken down in an anaerobic environment = one that has little or no oxygen – Bottoms of deep lakes, swamps, and shallow seas Types of Fossil Fuels: Organic matter is eventually converted into coal, crude oil or natural gas.

26. Fossil fuels are our dominant source of energy high-energy content efficient to burn, ship, and store generate electricity a secondary form of energy that is easier to transfer and apply to a variety of uses

27. Nuclear Power

28. Raise your hand if you heard a beep from the machine. Why are some of us more radioactive than others? Are those people dangerous? Do they need immediate treatment from the hospital? Will they be radioactive tomorrow? By the end of this lesson you should know the answers to these questions.

29. What is radiation? Q. Do we have to see it for it to be radiation? Q. Are all forms of radiation harmful? A. The real difference between helpful and harmful is usually the amount of radiation and the target. For example, a flashlight aimed at the ceiling is safe, while one aimed at your eyes is dangerous.

30. What are some sources of radiation? Infrared Visible light waves Microwaves Radio waves X rays Alpha Beta Gamma

33. Classification of Radiation Most of what we are exposed to every day is called non-ionizing radiation. Includes radio, TV, and microwaves. It also includes the light and heat from light bulbs. Ionizing radiation has sufficient energy to knock electrons off of atoms and turn them into ions. This radiation comes from atoms and includes X-rays.

34. What is radioactive decay? Radioactive isotopes undergo radioactive decay, the spontaneous release of material from the nucleus. – changes the radioactive element into a different element. For example, uranium-235 ( 235 U) decays to form thorium- 231 ( 231 Th). – The original atom (uranium) is called the parent and the resulting decay product (thorium) is called the daughter. – emits a great deal of energy that can be captured as heat. Nuclear power plants use this heat to produce steam that turns turbines to generate electricity.

35. How is radioactive decay measured? A. Record the average rate of decay of a quantity of a radioactive element (commonly stated in terms of the element’s half-life: the time it takes for one-half of the original radioactive parent atoms to decay) Q. Why is an element’s half-life a useful parameter to know? A.Because some elements that undergo radioactive decay emit harmful radiation so knowledge of the half-life allows scientists to determine the length of time that a particular radioactive element may be dangerous. Scientists can calculate the period of time that people and the environment must be protected from depleted nuclear fuel, like that generated by a nuclear power plant. Q.What does this mean in terms of storage of waste? A. As it turns out, many of the elements produced during the decay of 235 U have half-lives of tens of thousands of years and more. From this we can see why long- term storage of radioactive nuclear waste is so important.

36. Long after nuclear fuel can produce enough heat to be useful in a power plant, it continues to emit radioactivity. At this point, it is considered radioactive waste. Because radioactivity can be extremely damaging to living organisms, radioactive materials must be stored in special, highly secure locations. Three types of waste regulated by the government high-level waste - used fuel rods (highest priority) low-level waste - contaminated protective clothing, tools, rags, other items used in plant maintenance uranium mine tailings - residue left after uranium ore is mined and enriched. Uranium-235 has a half-life of 704,000,000 years, which means that 704 million yrs from today, a sample of 235 U = ½ as radioactive as it is today. In another 704 million years = 1/4 as radioactive as it is today. Radiation can be measured in becquerel (Bq) = rate of sample decays Curie = another measurement of radiation. Spent fuel rods remain a threat to human health for 10 or more half-lives!

37. End of Lesson 2

38. “Half Life of a Penny” Activity Read the background Follow the procedure, using a can of pennies Answer the questions Graph your data

39. Why is knowing the half life important? The measurement of isotopes has many applications in environmental science as well as in other scientific fields. For example, carbon in the atmosphere exists in a known ratio of the isotopes carbon-12 (99%), carbon-13 (1%), and carbon- 14 (which occurs in trace amounts, on the order of one part per trillion). Carbon- 14 is radioactive and has a half-life of 5,730 years.Carbon-13 and carbon-12 are stable isotopes. Living organisms incorporate carbon into their tissues at roughly the known atmospheric ratio. But after an organism dies, it stops incorporating new carbon into its tissues. Over time, the radioactive carbon-14 in the organism decays to nitrogen-14. By calculating the proportion of carbon-14 in dead biological material—a technique called carbon dating— researchers can determine how many years ago an organism died.

40. Geiger Counters

41. End of Lesson Homework – do questions 7 & 8 on APES Energy Problems

42. Fission The naturally occurring isotope 235 U, as well as other radioactive isotopes, undergoes a process called fission. Fission - a nuclear reaction in which a neutron strikes a relatively large atomic nucleus, which then splits into two or more parts. This process releases additional neutrons and energy in the form of heat. The additional neutrons can, in turn, promote additional fission reactions, which leads to a chain reaction of nuclear fission that gives off an immense amount of heat energy. In a nuclear power plant, that heat energy is used to produce steam, just as in any other thermal power plant. However, 1 g of 235 U contains 2 million to 3 million times the energy of 1 g of coal.

44. Nuclear reactors A properly designed nuclear reactor will harness the kinetic energy from the three neutrons in motion to produce a self- sustaining chain reaction of nuclear fission. The by-products of the nuclear reaction include radioactive waste that remains hazardous for many half-lives—that is, hundreds of thousands of years or longer.

46. Types of Nuclear Reactors - FISSION Nuclear fission – All commercial power reactors that generally use uranium and its product plutonium as nuclear fuel – Fission reactors can be divided roughly into two classes, depending on the energy of the neutrons that sustain the fission chain reaction: Thermal reactors - (most common) use slowed or thermal neutrons to keep up the fission of their fuel. Fast neutron reactors (less common) use fast neutrons to cause fission in their fuel. No neutron moderator & use less- moderating coolants. More difficult to build and more expensive to operate.

47. Types of Nuclear Reactors - FUSION Nuclear fusion – The reaction that powers the Sun and other stars, where lighter nuclei are forced together to produce heavier nuclei  heat experimental technology, generally with hydrogen as fuel Requires a reactor that will heat material to temperatures 10x those in the core of the Sun

48. Properly Functioning Nuclear Power Plants Objective: harness the heat energy from fission to make steam Must be able to slow down the fission reaction to allow reactions to take place at the right speed. (Add water!) Control rods can be inserted to absorb excess neutrons to slow down or stop the fission reaction. Slowing down must occur to avoid a meltdown

49. Where does the Uranium come from? It may take 2000 pounds of uranium ore to produce 6.6 pounds of nuclear fuel. Miners remove large amounts of host rock, remove the uranium, leave rock pile behind (typically seen in Australia, western US and parts of Canada). Although mining requires fossil fuels and leaves behind a disturbed area, a much smaller volume and mass of uranium is needed to generate a quantity of electricity versus coal.

51. Pros & Cons of Nuclear Energy No air pollution (CO 2 emissions), therefore “clean” energy Allows for independence from fossil fuel resources if limited to begin with. Commonly used in France (70% + ), Germany, Spain, Japan… (US = 20%) Expensive to build, partly b/c of protests & legal battles Where to put radioactive waste? Fear of nuclear weapons Possibility of accidents

52. Accidents that made history March 28, 1979, at the Three Mile Island nuclear power plant in Pennsylvania, operators did not notice that a cooling water valve had been closed the previous day. This oversight led to a lack of cooling water around the reactor core, which overheated and suffered a partial meltdown. The reactor core was severely damaged, and a large part of the containment structure became highly radioactive. An unknown amount of radiation was released from the plant to the outside environment.

53. Chernobyl, Ukraine 10x worse than Hiroshima! April 26, 1986 Routine test + safety regulation violation (deliberate disconnect of emergency cooling systems and control rod removal) = Overheating  BOOM! http://www.youtube.com/watch?v=bSRC1_OZ PIg http://www.youtube.com/watch?v=bSRC1_OZ PIg

54. Radiation & Human Health

57. Alpha, beta & gamma decay https://www.khanacademy.org/science/chemistry/radioactive-decay/v/types-of-decay Khan Academy explaining how these different types decay Alpha Decay: 2:50-6:08 Beta decay: 6:09 – 8:50 Gamma decay: 11:50 – 12:14 Explanation of alpha, beta & gamma radiation and how to protect from them, and how they can enter the body and biological tissue http://www.youtube.com/watch?v=27qSAqafQ6o 3 types of rays and degree of penetration http://www.youtube.com/watch?v=VTHQYjkCqV0http://www.youtube.com/watch?v=VTHQYjkCqV0

58. 1.Which type of radiation do you think travels the fastest? Why? 2.Which is the heaviest? 3.Which one will move through you the farthest? 4.Which one is the most dangerous from the outside? To which body parts? 5.Which ones might be the most dangerous if they got inside you and moved through the soft tissues of the body? Why?

59. Radiation Predictions-Nuclear Equations

60. Radiation Card Game Rules for Predicting Nuclear Reactions Alpha decay involves the loss of a 4 2 He so the mass decreases by 4 and the atomic number decreases by 2. A beta decay involves the loss of one electron from the nucleus so the mass remains constant and the atomic number increases by 1.