Why Shake Your Fever Thermometer? - and More

If you have ever wondered (as I have) how a fever thermometer actually works (but have never felt good enough while you were wondering to do any investigation) then you should look at this article in "How Things Work", a feature of The Physics Teacher edited by H. Richard Crane of the Physics Department of University of Michigan. Not only does he explain how these common thermometers "hold" the maximum temperature, but also why the mercury column has to be so small that you need the built-in cylindrical lens to read it.