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<p>Seeing we touched on radioactive decay at the YAPA meeting tonight, thought these two papers by Edward Prather might be of interst.
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<p> </p>
<p>He covers the misconceptions of students, </p>
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<font size="2" face="BookAntiqua"><font size="2" face="BookAntiqua">
<p align="left">"Many students provided responses consistent with</p>
<p align="left">the belief that radioactive objects disappear or</p>
<p align="left">disintegrate during radioactive decay. These students</p>
<p align="left">often predict that the mass, volume, and number of</p>
<p align="left">atoms for radioactive objects decrease by half during a</p>
<p align="left">half-life. For many students it appears that the word half</p>
<p align="left">acts like a mental trigger that leads the student to divide</p>
<p align="left">by two. These students appear to perform this division</p>
<p align="left">without any further thought about the radioactive decay</p>
<p align="left">process. These reasoning difficulties likely stem from</p>
<p align="left">students' inability to properly reason about the</p>
<p align="left">radioactive decay process at the atomic (or nuclear) level.</p>
<p align="left">Unfortunately, even for those students who do have an</p>
<p align="left">understanding of radioactivity that involves the atom,</p>
<p align="left">they often also predict that half of the radioactive object</p>
<p>will disappear after a half-life."</p>
<p> </p>
<p>Be careful how you model, since the ideas of the models stick with students a long time.</p>
<p>Robert Pendzick</p>
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