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Radioactivity: Expect the unexpected - Steve Weatherall

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Neutrons don’t change into protons. Except, sometimes, they do. Radioactivity is the process under which the nucleus can change spontaneously from one element to another. Steve Weatherell suggests that we acknowledge both the usefulness and danger inherent in harvesting radioactivity.

Imagine a source containing 8 million radioactive nuclei. For this particular material, in one hour, half of the nuclei decay. Thus, after one hour, 4 million nuclei have decayed and there are 4 million remaining. Write down the numbers of nuclei remaining after each subsequent hour for the next four hours. Use the numbers to sketch a graph of ‘Number of remaining nuclei’ against ‘Time in hours’. This is the characteristic shape of exponential decay.

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  • Animator Eugene Uymatiao
  • Educator Steve Weatherell
  • Narrator Steve Weatherell

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