The mystery and fascination with perhaps mankind's most dangerous field of knowledge--which also presents one of the world's most important challenges--appeals to young and curious minds. High school science teachers can provide the opportunity to sate the curiosity and also provide opportunity for confidence as the students are able to understand something seemingly so beyond their reach. The concepts of nuclear physics and its applications are surprisingly simple once you can get past the initial awe of the subject.
Instructions
Instructions
1. Present descriptions and concepts and terminology of the atomic nuclear structure and its physical properties, including electron configuration. Explain units of measurements, atomic numbers, and mass. Describe the difference between fusion, which is a nuclear reaction in which nuclei with a low atomic number fuse together to form a heavier nucleus; and nuclear fission, which is when a heavy nucleus splits. Review the periodic table of the elements to aid in this discussion.
2. Define radioisotopes and radioactivity. Discuss alpha, beta, gamma, and other types of emissions from radioactive isotopes, which are positively or negatively charged particles emitted during the decay of unstable atoms. Include curies and nano-curies. Also explain limits and recommended exposures to these types of radiation.
A dose of radioactivity is measured in millerems (mrems). According to the American Nuclear Society, an average dose is 360 mrems is average for an American exposed to a variety of sources, and 5,000 mrems is the international standard for a nuclear worker. This discussion provides opportunity to warn of the chemical, physiological, and genetic damage that exposure to radioactive emissions can cause.
3. Briefly explain the process of modern in-situ uranium mining and enrichment just to give students the context of applied nuclear physics. Describe the modern centrifuge process, in which uranium is turned into uranium hexa-floride gas to separate U-235 from U-238 because U-235 is fissionable and desirable as fuel for nuclear reactors. The byproduct, or U-238, is called "depleted uranium." The heavy metal is used as ammunition and tank armor.
4. Describe the mechanics and physics of a nuclear reactor and chain reaction and the term "critical mass."
Simply put, processed U-235 is made into little pellets which are placed into rods. When the excited electrons from an unstable atom escape, they run into the other atoms and cause their electrons to escape. A nuclear power plant is basically a controlled chain reaction, which gets extremely hot. They use this heat to make steam, which is converted into electricity.
Go over various fuels and fuel mixtures that are currently being experimented with. Also talk about the used fuel rods and the cooling process. Many reactors offer tours of their facilities.
5. Discuss the by-products of nuclear power, including plutonium and other transuranics, which are new elements and products of uranium, made in the reactor. Describe the use of plutonium nuclear bombs used by the United States, including Little Boy and Fat Man, and the detonation mechanism. You may want to coordinate with a history teacher to educate students about the dropping of atomic bombs on Hiroshima and Nagasaki in Japan in 1945 and the dilemma of the scientists who first developed nuclear weapons at Los Alamos National Laboratory in New Mexico. This is also an opportunity to discuss current nuclear proliferation.
6. Explain other uses for radioactive products made from the by-products like depleted uranium and the chemical effects of a heavy metal inside the body. Include medical uses, such as X-rays, chemotherapy, and other uses of radiology. The U.S. Department of Defense has done the most research on the effects of depleted uranium on the body.
7. Teach the students scientific notation, exponential terms, and--using large figures--basic algebraic equations to determine radioactive half-lives. Have students describe the processes of radioactive decay, interaction, detection, and measurements through mathematical functions. These can be assigned throughout the course.
Tags: depleted uranium, chain reaction, heavy metal, nuclear power, other uses
