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Chemistry 25.4

Chemistry 25.4. 25.4. Radiation in Your Life.

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Chemistry 25.4

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  1. Chemistry 25.4

  2. 25.4 Radiation in Your Life • In a smoke detector, radiation from the Americum nuclei ionizes the nitrogen and oxygen in smoke-free air, allowing a current to flow. When smoke particles get in the way, a drop in current is detected by an electronic circuit, causing it to sound an alarm. You will learn about some of the other practical uses of radiation.

  3. 25.4 Detecting Radiation • Detecting Radiation • What are three devices used to detect radiation?

  4. 25.4 Detecting Radiation • Ionizing radiation is radiation with enough energy to knock electrons off some atoms of the bombarded substance to produce ions. • Devices such as Geiger counters, scintillation counters, and film badges are commonly used to detect radiation.

  5. 25.4 Detecting Radiation • Radiation can produce ions, which can then be detected, or it can expose a photographic plate and produce images.

  6. 25.4 Detecting Radiation • Geiger Counter • A Geiger counter uses a gas-filled metal tube to detect radiation.

  7. 25.4 Detecting Radiation • Scintillation Counter • A scintillation counter uses a phosphor-coated surface to detect radiation.

  8. 25.4 Detecting Radiation • Film Badge • A film badge consists of several layers of photographic film covered with black lightproof paper, all encased in a plastic or metal holder.

  9. 25.4 Using Radiation • Using Radiation • How are radioisotopes used in medicine?

  10. 25.4 Using Radiation • Neutron activation analysis is a procedure used to detect trace amounts of elements in samples. • Neutron activation analysis is used by museums to detect art forgeries, and by crime laboratories to analyze gunpowder residues.

  11. 25.4 Using Radiation • Radioisotopes can be used to diagnose medical problems and, in some cases, to treat diseases.

  12. 25.4 Using Radiation • This scanned image of a thyroid gland shows where radioactive iodine-131 has been absorbed.

  13. 25.4 Section Quiz. • 25.4.

  14. 25.4 Section Quiz. • 1. Ionizing radiation can remove _______ from atoms. • protons • neutrons • positrons • electrons.

  15. 25.4 Section Quiz. • 2. Which of the following is NOT a device used to detect radiation? • geiger counter • scintillation counter • film badge • radioisotope

  16. 25.4 Section Quiz. • 3. Choose the correct words for the space. When a tumor is treated by radiation, more cancer cells than normal cells are killed because cancer cells ____________ than normal cells. • are more susceptible to damage because they grow faster • absorb more radiation because they are larger • grow slower • are smaller

  17. 25.4 Section Quiz. • 4. How do scientists detect thyroid problems? • with teletherapy • by neutron activation analysis • using an iodine-131 tracer • using a radioisotope sealed in a gold tube

  18. Concept Map • Concept Map 25. Solve the Concept Map with the help of an interactive guided tutorial.

  19. END OF SHOW

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