Periodic Table of the Elements The Actinide Series Teacher s Guide

Transcription

1 Teacher s Guide oneone oee Grade Level: 9 12 Curriculum Focus: Physical Science Lesson Duration: Two class periods Program Description The radioactive actinide series shines a light on the dangers and benefits of nuclear energy. Discover how the chemical properties of elements such as uranium and americium can make them both harmful and helpful to society and explore the science and applications of nuclear fission. Lesson Summary Students research the science behind harnessing nuclear energy and the development of the atomic bomb. They hold a debate where one team argues that the work led to necessary or positive outcomes. The other team argues that the problems have outweighed the advantages. After the debate students will assess which side presented a more compelling case. Onscreen Questions Part 1, Exploring the Actinides, Uranium: Stealth Boomer, Americium: Smoke Signals, and Californium: Cancer Killer What are some properties of the actinide elements? What is the relationship between radiation and cancer? Part 2, The Bomb: End of Innocence Why did scientists start working on atomic power? Why were scientists uneasy about working on the Manhattan Project? Lesson Plan Student Objectives Write a description of the science involved in harnessing nuclear energy and the development of the atomic bomb.

2 Teacher s Guide 2 Write a description of how scientists collaborated to build the first atomic bomb. Debate the positive and negative outcomes of harnessing nuclear energy and creating the atomic bomb. Materials Periodic Table of the Elements: program Paper and pencils Computer with Internet access Procedures 1. Begin the lesson by asking students to write their initial thoughts on a piece of paper about creating the atomic bomb. Ask students if this was a positive or negative development and have them write any facts supporting their views. It is of no consequence if students do not have enough knowledge to form an opinion. Have them put away the piece of paper away until the end of the lesson. 2. Have students watch The Bomb: End of Innocence, a segment in Periodic Table of the Elements:. Tell students that harnessing nuclear energy and the development of the atomic bomb remains controversial. During the lesson, students will learn about the events leading up to the development of the atomic bomb and debate whether it was a positive or negative scientific endeavor. 3. Divide students into two teams. Have one team take the position that the development of the atomic bomb was a worthwhile pursuit. This side will argue that the work was important and led to the necessary and positive outcomes. The other side will argue that the problems that have resulted from the development of the atomic bomb outweigh the advantages. 4. Give students time in class to prepare for the debate. As they gather information, ask them to consider the following questions. What science was involved in the development of the atomic bomb? (Scientists had to learn how to split the nucleus of an atom, a process called fission. They used uranium, the heaviest element in nature. They bombarded its nucleus with a neutron, and the collision caused it to split. The result was a chain reaction that released great amounts of energy.) Who were the scientists involved in creating the atomic bomb? (The scientists included Niels Bohr, J. Robert Oppenheimer, David Bohm, Otto Frisch, James Franck, and Edward Teller, who had emigrated from Europe to escape the Nazis during World War II.)

3 Teacher s Guide 3 How did the scientists feel about the creating the bomb? (Some felt they should not use their skills in the service of politics. In fact, some felt so strongly that they signed a petition not to use the bomb on moral grounds.) What are some positive effects of the development of nuclear energy? (The power of nuclear energy runs power plants, and some forms of nuclear energy are used in radiation therapy to treat cancer.) What are the overall effects of the development of the atomic bomb? (The development of the atomic bomb meant that a weapon could destroy the world. It also ushered in the Cold War, as other nations developed atomic bombs, making a nuclear war possible. The struggle over nuclear weapons led to a standoff between the Soviet Union and the United States that lasted more than 40 years.) 5. Students can find more information about this topic on the following Web sites After students have completed their research for the debate, have each team write an opening argument and that each is prepared to challenge opposing arguments. 7. Hold the debate during the next class period. Give each team time to present an opening argument and to rebut the opposing team. 8. Discuss the outcome of the debate. Did one team win? If so, why? What made its arguments more compelling than the other s? 9. Conclude the lesson by asking students to revisit the thoughts they wrote at the beginning of the lesson. Have their ideas changed as a result of this activity? If so, how? Assessment Use the following three-point rubric to evaluate students work during this lesson. 3 points: Students wrote an in-depth description of the science involved in the development of the atomic bomb; wrote a clear description of how scientists collaborated; and presented clear and persuasive arguments in the class debate. 2 points: Students wrote a satisfactory description of the science involved in the development of the atomic bomb; wrote a satisfactory description of how scientists collaborated; and presented adequate arguments in the class debate. 1 point: Students had difficulty or did not write a description of the science involved in the development of the atomic bomb; did not write a description of how scientists fro collaborated; and did not present complete arguments in the class debate.

4 Teacher s Guide 4 Vocabulary actinide series Definition: Rare elements with unstable nuclei found in period 7 on the periodic table of the elements Context: Most elements in the actinide series were made artificially; only thorium and uranium are found in nature. atomic bomb Definition: A weapon built by harnessing the power of uranium and its ability to produce huge amounts of energy Context: Many scientists involved in creating the atomic bomb had serious misgivings about whether scientific gains should be used for destructive purposes. fission Definition: The splitting of the nucleus of an atom after being hit by a neutron, resulting in a chain reaction and producing huge amounts of energy Context: A key scientific breakthrough in the development of the atomic bomb was the ability to cause fission. Manhattan Project Definition: The code name given to the top-secret scientific efforts to build an atomic bomb Context: The Manhattan Project began in 1938, and by 1945 nearly 200,000 people were working in its many laboratories and factories. nucleus Definition: The part of an atom containing positively charged protons and neutrons that undergoes fission Context: All elements in the actinide series share the characteristic of an unstable nucleus. uranium Definition: One of two elements in the actinide series found in nature; used in the first atomic bomb Context: Uranium s nucleus contains 92 protons. periodic table of the elements Definition: An organization of Earth s elements arranged by atomic number, or the number of protons in an element s nucleus Context: The actinide series are found at the bottom of the periodic table of the elements, in period 7.

5 Teacher s Guide 5 Academic Standards Mid-continent Research for Education and Learning (McREL) McREL s Content Knowledge: A Compendium of Standards and Benchmarks for K 12 Education addresses 14 content areas. To view the standards and benchmarks, visit This lesson plan addresses the following national standards: Physical Sciences: Understands the structure and property of matter Physical Sciences: Understands sources and properties of energy Nature of Science: Understands the scientific enterprise Language Arts Viewing: Uses viewing skills and strategies to understand and interpret visual media National Academy of Sciences The National Academy of Sciences provides guidelines for teaching science in grades K 12 to promote scientific literacy. To view the standards, visit this Web site: This lesson plan addresses the following national standards: Physical Science Structure and properties of matter Physical Science Interactions of energy and matter History and Nature of Science Science as a human endeavor Credit Marilyn Fenichel is a writer, editor, and educational consultant. Support Materials Develop custom worksheets, educational puzzles, online quizzes, and more with the free teaching tools offered on the Discoveryschool.com Web site. Create and print support materials, or save them to a Custom Classroom account for future use. To learn more, visit

6 Teacher s Guide 6 DVD Content This program is available in an interactive DVD format. The following information and activities are specific to the DVD version. How To Use the DVD The DVD starting screen has the following options: Play Video This plays the video from start to finish. There are no programmed stops, except by using a remote control. With a computer, depending on the particular software player, a pause button is included with the other video controls. Video Index Here the video is divided into sections indicated by video thumbnail icons; brief descriptions are noted for each one. Watching all parts in sequence is similar to watching the video from start to finish. To play a particular segment, press Enter on the remote for TV playback; on a computer, click once to highlight a thumbnail and read the accompanying text description and click again to start the video. Curriculum Units These are specially edited video segments pulled from different sections of the video (see below). These nonlinear segments align with key ideas in the unit of instruction. They include onscreen pre- and post-viewing questions, reproduced below in this Teacher s Guide. Total running times for these segments are noted. To play a particular segment, press Enter on the TV remote or click once on the Curriculum Unit title on a computer. Standards Link Selecting this option displays a single screen that lists the national academic standards the video addresses. Teacher Resources This screen gives the technical support number and Web site address. Video Index I. Exploring the Actinide Series (5 min.) The radioactivity of the actinide elements can be beneficial when it is used in cancer treatments and as a source of heat and power. II. Uranium: Stealth Boomer (7 min.) Classified as a metal in the actinide series, uranium is a highly radioactive element used to power nuclear weapons and reactors. III. Americium: Smoke Signals (6 min.) Learn about americium and discover why this element is used in smoke detectors.

7 Teacher s Guide 7 IV. Californium: Cancer Killer (5 min.) See why the radioactive element californium holds great promise in the field of cancer treatment. V. The Bomb: End of Innocence (22 min.) The use of the atomic bomb changed the world forever. Examine the events that led up to the dropping of the bomb on Hiroshima. Curriculum Units 1. All About the Actinides Q: What do you know about radioactive elements? Q: What makes the actinides unique among the groups of elements in the periodic table? A: All actinides are radioactive and most are artificial. Those heavier than uranium are artificially produced in a laboratory or as a byproduct of nuclear reaction. 2. Uranium: Properties and Uses Q: What uses of uranium do you know of? A: Answers may include that uranium is used in fuel for nuclear weapons and reactors. Q: Describe an atom of the most common form of uranium. A: In the most common form, an atom of uranium has 92 positively charged protons and 146 uncharged neutrons in its nucleus. It has 92 negatively charged electrons found in seven shells surrounding its nucleus. 3. Uranium and Nuclear Submarines Q: Do you think that nuclear weapons deter or encourage war? Q: How does the nuclear reactor on a stealth submarine work? A: Neutrons split the uranium in the nuclear reactor, releasing more neutrons and generating heat. The heat produces steam, which drives the turbine that powers the sub and the generator

8 Teacher s Guide 8 that provides it with electricity. Modern nuclear subs can go for more than 20 years without refueling. 4. Americium: Properties and Uses Q: What do you know about the element americium? Q: What is the only known practical use of americium? A: The only current practical application of americium is in smoke detectors. 5. Smoke Detectors Q: How do you think smoke detectors work? Q: How do americium-based ionizing smoke detectors work? A: The americium in smoke detectors undergoes alpha decay, so it is constantly giving off alpha particles. The particles are positively charged, and by interacting with other atoms in the air they create a small area of ionized air within the smoke detector. A small amount travels across the ionized air. When smoke is present, the soot absorbs the alpha particles and the ions are not formed. Without them, electricity is disrupted, which sets off the alarm. If the smoke dissipates, the ionization resumes and the alarm will stop. 6. Californium: Properties and Uses Q: What artificial elements do you know of? Q: How many known isotopes does californium have? A: Eight. 7. Treating Cancer Q: What are some types of cancer treatment? Q: Why is californium a promising element for cancer treatment? A: The high-energy neutron radiation of californium has proved effective in treating cancers

9 Teacher s Guide 9 that do not respond to other types of radiation therapy and cancers in advanced stages of development. 8. The Beginnings of Nuclear Science Q: Do you think scientists are always aware of the consequences of their discoveries and inquiries? Q: How did Ernest Rutherford and his students regard their work in nuclear science? A: The scientist Ernest Rutherford and his students did not believe their work would produce anything destructive. Rutherford himself did not believe that we would be able to utilize the energy contained within an atom s nucleus; in fact, he himself believed it to be impossible. 9. Splitting an Atom Q: What do you think are important discoveries in physics? Q: How did splitting an atom affect the scientific community worldwide? A: Scientists became concerned that if Nazi Germany under Hitler could split an atom and make an atomic bomb, it would win World War II. Those who had been impartial or objective about splitting an atom faced the moral dilemma of whether to work on creating nuclear weapons. Tensions increased in the scientific community, and the United Kingdom and the United States developed top-secret plans to build an atom bomb. 10. Building the Bomb Q: If you were a nuclear scientist, what kinds of work would you want to do? Q: What made Los Alamos, New Mexico, an ideal location for building an atomic bomb? A: Los Alamos was very isolated, so the scientists could work together and confer openly, while maintaining carefully guarded separation and security. 11. The U.S. and U.K. Exclude Russia Q: Have you ever kept an important secret from a friend or ally?

10 Teacher s Guide 10 Q: Do you think the United States and United Kingdom should have involved the Russians in the Manhattan Project? 12. Using the Atomic Bomb Q: Have you ever seen or experienced an explosion? Q: How might the outcome of World War II been different if the U.S. had not dropped the atomic bomb on Japan?