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Explores what makes elements radioactive and which elements are always radioactive.

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How Alarming!

How Alarming!

Credit: R/DV/RS
Source: http://www.flickr.com/photos/redvers/523072182/
License: CC BY-NC 3.0

You probably have smoke detectors like this one in your home. They are one of the most important life-saving devices you can use. Did you know that many smoke detectors contain radioisotopes?

News You Can Use

  • Radioisotopes are radioactive isotopes, or isotopes that emit charged particles and energy from the nucleus.
  • The radioisotopes in smoke detectors emit alpha particles. An alpha particle is tiny particle consisting of two protons and two neutrons.
  • Alpha particles explain how a smoke detector works. To see how, watch this video: 


Can You Apply It?

Learn more about how smoke detectors work at the links below. Then answer the questions that follow.

  1. What radioisotope is found in a smoke detector? How much of this radioisotope is present in a smoke detector?
  2. What does the radioisotope in a smoke detector normally do, that is, in the absence of smoke? How does it do this?
  3. What happens if smoke enters a smoke detector?
  4. What is a MOSFET? What role does it play in a smoke detector? In general terms, how does it work?
  5. Radioactivity can be harmful to living things. Why isn’t the radiation produced by the radioisotope in a smoke detector dangerous?

Image Attributions

  1. [1]^ Credit: R/DV/RS; Source: http://www.flickr.com/photos/redvers/523072182/; License: CC BY-NC 3.0

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