To explore how a nuclear accident can affect biological systems.
By examining the case of the Chernobyl nuclear meltdown in 1986, students study the adverse effects of high doses of radiation on biological systems. This concept is best elucidated by the use of nuclear energy. In comparison to the burning of fossil fuels, the fission of the nuclei of heavy elements releases an immense quantity of energy in relation to the mass of material used. However, the waste products of fission are highly radioactive and remain so for thousands of years. (Science for All Americans, p. 115.) Technological advances are always associated with some degree of human error. The 1986 Chernobyl meltdown in the former Soviet Union is an unfortunate example of human error and lack of safety measures. The resulting radioactivity has affected millions of people and the entire surrounding environment.
It is important when teaching these concepts to students that they also recognize that radiation has had positive effects as well. For example, the discovery of X rays in 1895 was a great breakthrough in diagnosing diseases because it enabled doctors to "see" inside the body without having to operate. Newer X-ray technologies such as CT (computerized tomography) scans have revolutionized the diagnosis and treatment of diseases affecting almost every part of the body.
Using The Chernobyl Disaster student esheet, refer students to Building Blocks of Life. Go over this page with students to review the levels of biological organization. Ask students to think about how nuclear radiation might affect life and discuss whether the effects of a nuclear disaster might be felt at every level of biological organization.
Tell students that they will now examine one toxic incident that occurred in 1986 in the Soviet Union. One of the four reactors at the Chernobyl generating system melted down, leading to the release of toxic radioactive chemicals over vast areas of Europe and the contamination of thousands of people. Refer students to The Chernobyl Disaster student esheet, which will guide them through an exploration of this issue. You can either discuss the esheet questions with the students in the classroom or direct them to use the Chernobyl's Effects student sheet provided. Answers can be found in The Chernobyl Disaster teacher key.
If, during the course of this lesson, students become concerned about their own exposure to radiation, you may wish to point out to them that most of the radiation that we are receiving is naturally occurring background radiation over which we have little control. Some level of exposure to additional radiation is unavoidable. It appears, however, that the cancer risk from very small-dose exposure is quite low.
Distribute the Chernobyl Disaster's Effects on Biological Systems student sheet. This student sheet asks students to determine how the toxic radioactive chemicals released by the Chernobyl meltdown affected each level of biological organization. Students should draw upon the knowledge gained from the online readings. Students can work in small groups to complete the student sheet. Then discuss the answers with the class. The Chernobyl Disaster teacher sheet provides possible answers.
To learn more about the Chernobyl disaster, have students watch the BBC's World Report. This audio-visual report is 27 minutes long and describes the toxic effects of the Chernobyl meltdown on human life and the environment.
Radiation Health Effects Information Resource, from the Baylor College of Medicine, provides an extensive amount of information about the health effects of radiation, especially as they pertain to the Chernobyl disaster. Particularly helpful are the "Questions and Answers."