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Nuclear Energy

Nuclear Energy. April 4, 2013. A.) Nuclear Radiatoin. the matter and energy that are released from the nucleus during radioactive decay. B.) What does radioactive mean?.

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Nuclear Energy

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  1. Nuclear Energy April 4, 2013

  2. A.) Nuclear Radiatoin • the matter and energythat are released from the nucleus during radioactive decay

  3. B.) What does radioactive mean? • Radioactive materials have unstable nuclei, which go through changes by emitting particles or releasing energy to become stable • Call this nuclear decay

  4. C. Types of Radiation 1. Alpha Particle: a positively charged atom that consists of two protons and two neutrons • Do not travel far through materials (cannot pass through a piece of paper) • Symbol: 42He

  5. How would emitting an alpha particle affect the properties of the atom? • The atomic number would… • Go down by 2!! • A new element!!! • The mass would… • decrease by 4!!

  6. 2. Beta Particle: a negatively charged electron emitted during radioactive decay • Fast-moving • Can penetrate sheet of paper, but stopped by piece of aluminum or 10mm of wood • Symbol: 0-1e

  7. HUH? An electron from a NUCLEUS??? • In the 1930’s we discovered that a neutron can decay to form a proton and electron.

  8. How would emitting beta particle affect the properties of the atom? • The atomic number would… • Increase by 1!! • New element!!! • The mass would… • NOT CHANGE

  9. What would happen to the identity of the atom? • It would change to be a new element because it has an extra proton!

  10. 3. Gamma Rays: high-energy radiation emitted during radioactive decay and nuclear fission • Gamma rays are a form of electromagneticenergy, not matter like the other three. • Not stopped by clothing or most building materials, so are much more dangerous (must use lead) • Symbol:

  11. Neutron Emission • Like Alpha and Beta radiation, these consist of matter emitted from an unstable nucleus. • This is how neutrons were first discovered • Able to travel very far • A block of lead 15 cm thick is required to stop them. • Symbol: 10n

  12. Nuclear Decay • Page 287- let’s take a look… • P 289- lets do the problems!

  13. III. Decay Rates • Half-life: time required for half of a sample of radioactive substance to decay • Use these decay rates to tell the age of rocks and fossils (radiometric dating) • Carbon-14 is a common isotope used in radiometric dating

  14. Half-life Lingo… • Original element = parent atoms • As the original element decays to a new one =daughter atoms

  15. C-14 applications today

  16. Math Skills p 291 • Now let’s practice…p 292 #1-5

  17. IV.) Nuclear Forces • A. The stability of a nucleus depends on the nuclear forces that hold it together. • B. These forces are between protons and neutrons (STRONG NUCLEAR FORCE) • C. Neutrons contribute to nuclear stability • a. Too many protons or neutrons can cause a nucleus to become unstable and decay.

  18. V.) Nuclear Reactions A) Nuclear Fission: the process by which a nucleus splits into two or more smaller atoms and releases neutrons and energy • In nuclear fission, tremendous amounts of energy can be produced from very small amounts of mass (Fig. 7 p.295)

  19. Converting Mass into Energy • Albert Einstein introduced the mass-energy equation: E = mc2 • According to the law of conservation of mass and energy, the total amount of mass and energy remains constant

  20. Mass defect?? • What did you learn in the reading guide? • Where does that small amount of mass go? • converted into energy

  21. 3. Nuclear Power a. In controlled chain reactions, heat from the reaction can be used to generate electrical energy b. Critical Mass: the minimum amount of a substance that can undergo a fission reaction and can also sustain a chain reaction.

  22. 4. Triggering a Chain Reaction • Chain reaction: a continuous series of nuclear fission reactions [Fig 8 p.296] • Nuclear fission follows a pattern of a chain reaction; The speed of a chain reaction can vary

  23. Nuclear Energy From Fission • Nuclear power plants generate about 20% of electricity in the U.S. • Controlled fission of uranium-235 in a fission reactor • Don’t emit air pollutants, but have other safety concerns • 1986: meltdown of reactor at Chernobyl nuclear power plant in Ukraine

  24. 1 5 2 6 3 4 7 8

  25. 6. Nuclear Weapons a. Nuclear weapons are designed to have an uncontrolled chain reactions

  26. Nuclear Fusion:the process in which smaller nuclei fuse together at high temperatures and release energy • In nuclear fusion, tremendous amounts of energy can be produced from very small amounts of mass • Releases more energy than nuclear fission

  27. Requires extremely high temperatures—i.e. Sun reaches temp of 10,000,000oC • Fusion may someday provide clean and efficient source of electricity

  28. Two problems creating a fusion reactor: • Need very high temperatures to start reaction • Must contain plasma

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