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Radioactivity

Radioactivity. Chapter 9 Nuclear Changes. Radioactivity. Radioactive materials have unstable nuclei. They emit particles/energy to become stable. Isotopes are generally radioactive. Why do you think that is?. Four Different Types of Radioactivity. Alpha Protons and Neutrons are emitted

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Radioactivity

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  1. Radioactivity Chapter 9 Nuclear Changes

  2. Radioactivity • Radioactive materials have unstable nuclei. • They emit particles/energy to become stable. • Isotopes are generally radioactive. Why do you think that is?

  3. Four Different Types of Radioactivity • Alpha • Protons and Neutrons are emitted • Beta • 1 electron is emitted • Gamma • Light is emitted • Neutron • Neutrons are emitted

  4. So Why Is It Dangerous? • It’s not ALWAYS dangerous, but most of the time it is. • The energy/particles that are emitted travel through the air and hit the atoms it meets. This disturbs the atoms. • Do you think you want disturbed atoms in your body?

  5. How Do We Prevent too much Radiation Exposure?? • Shielding! • Shielding is the materials that are between the radioactive source and the detector or person. • The purpose of shielding is to reduce the amount of radiation that one person or object receives.

  6. Shielding • Alpha particles • Stopped by paper or the skin • Present little or no hazard external to body • Internal hazard (if it gets in the body) • Beta particles • Stopped by light metals (aluminium) and plastics • Internal and external hazard

  7. Shielding • Gamma rays • Stopped by very dense materials (lead, concrete) • Easily pass through the human body • Internal and external hazard • Neutrons • Stopped by materials containing hydrogen atoms, such as water, polyethylene, and concrete • Internal and external hazard

  8. Shielding: Alphas, Betas, Gammas and Neutrons

  9. Where Does the Radiation Come From? • The radiation you receive can be either Natural or Man-made

  10. Sources of Radiation: Natural • Cosmic: • Sun • Terrestrial: sources in the earth’s crust • Soil (radon) • Water • Vegetation (Bananas) • Internal: sources in the human body • Potassium-40 • Carbon-14 • Lead-210

  11. Sources of Radiation: Man-made • Medical • X-rays • Cancer treatments • Commercial • TV • Lantern mantels • Smoke detectors • Fuel cycle (nuclear power)

  12. Determining Your Personal Annual Radiation Dose

  13. Average Annual Dose to Ionizing Radiation • All living creatures constantly receive a certain amount of radiation from outer space, the soil, food we ingest or even the air we breathe. • The sources of radiation fall under two categories: natural and man-made, collectively known as background radiation. • The average annual personal dose from background radiation is approximately 350 mRem/year.

  14. What To Do • In this activity, you will estimate your personal annual radiation dose using the Background Information Worksheet provided. When doing this activity, keep in mind that the amount of • terrestrial radiation varies in different parts of the world due to different concentrations of uranium and thorium in soil. • cosmic radiation varies in different parts of the world due to differences in elevation and to the effects of the earth’s magnetic field.

  15. Procedure • Complete the worksheet and tally the total. • For central Ohio, the average elevation is about 825 feet above sea level • approximate dose is 28 mRem/year from cosmic radiation. • For every hour in an airplane, you receive 0.5 mRem • Make sure to use 30 mRem/year for the second entry. • In central Ohio, we are not within 50 miles of a power plant. However in southern Ohio, there are many coal plants along Ohio River.

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