The Madness of Stirring Hot Chocolate

Secondary School Science Teaching Methods

Adam Johnston & Sharon Ohlhorst

Stirring hot chocolate creates an interesting and not-easily-explained phenomenon[1].  After stirring the hot chocolate mix into the water, the tone produced by tapping the metal spoon on the bottom of the cup is relatively low, but gradually raises pitch.  Stirring the hot chocolate again will restore the lower tone, but it will rise just as before.

 

Explain why.

 

You should have one partner.  Together, you make up a research group.  This is your most valuable asset.  Also in your favor are the following:

 

C           Several different cups.

C           Almost endless supply of hot chocolate mix.

C           Spoons.

C                     Sources of hot and cool water.

C                     Any other various materials and objects that you may scrounge or discover.

 

In addition to explaining Awhy,@ explain what you are doing to answer the question.  That is, what is the method to your own madness?  Document this all in your notebook.

 

(Note: Your answer is not as important as your procedure.  Perhaps you should first guess at the answer, and then test your guess in as many ways as possible.  Continue with this process until you arrive at a Abest guess.@)

 

As you pursue scientific bliss and a quenching of your thirst for knowledge, ask yourself the following questions:

C                     Are you doing science?  How do you know?  What makes this scientific?

C                     What are you observing?  What are you inferring?  What’s the difference, and why does it matter?

C                     Is this pursuit something that you could do in your Earth/Life/Physical Science classroom?  Why not?  Why would you do something like this?  What is its point?

 


 

[1] Jearl Walker brings up this problem in The Flying Circus of Physics with Answers, p.  6 (problem #1.22).  Note that his answer is debatable.