Lesson One

Lesson Plan One Teacher: Angela Schneider Course: Physics Grade: 11-12 Topic: Nuclear Energy CLE(s): Describe how changes in the nucleus of an atom during a nuclear reaction (i.e., nuclear decay, fusion, fission) result in emission of radiation). Identify the role of nuclear energy as it serves as a source of energy for the Earth, stars, and human activity (e.g., source of electromagnetic radiation, thermal energy within mantle, nuclear power plants, fuel for stars). Objectives: The student will identify different types of radiation. The student will describe the half-life process and demonstrate how they are calculated. Materials needed: fill-in notes for each student, writing utensils Introduction: Ask students what they think of when they hear the word ‘radiation’. Write key points on the board. Radiation is all around us, yet we can’t see it, feel it, smell it, or taste it. It comes from the earth itself, space, and man-made sources. Content: Present content to the class, writing key points on the board. Students should follow along and complete the provided notes. Radiation is produced by unstable atoms. Unstable atoms eventually decay into stable atoms and the energy produced as the atom decays is radiation. Sample decay chain: Uranium-238 > Thorium-230 > Radium-226 > Radon-218 > Bismuth 214 > Lead-206 No one knows exactly how a radioactive element will decay, but there is a known pattern describing how long it will take a particular atom to lose half its radioactivity called the half-life. Formula used to calculate half-life: A_E=A_o×〖0.5〗^(t/t_□(1/2) ) A_E: the amount of the substance remaining A_o: the original amount of the substance t: elapsed time t_(1/2): half-life of the particular substance Example: If you originally had 157 grams of carbon-14 and the half-life of carbon-14 is 5730 years, how much would there be after 2000 years? Three different types of radiation: Alpha radiation: alpha particles: emitted from unstable isotopes +2 charge, slow, easily stopped (paper, skin), internal hazard (damages tissues and cells) Beta radiation: beta particles: high energy electrons, faster and lighter than alpha particles, can travel through skin, internal and external hazard, blocked by thin layers of metals and plastic Gamma radiation: gamma rays: high energy light – part of the electromagnetic spectrum, travels at the speed of light, internal and external hazard, blocked by thick materials like cement or steel Alpha, beta, and gamma radiation are classified as ionizing radiation, which is especially dangerous because it can change the chemical makeup of many living things. All exposure to radiation will have biological effects, but exposure to large amounts of radiation can cause genetic defects or cancer, causes ionization of atoms, which affect molecules, which may affect cells, which may affect tissues, which may affect the whole body. Conclusion: Tomorrow we will do two labs, focusing on radiation.