Heat Transfer Just Right

I could definitely see how this lesson could be used in my middle school class. To get my students motivated I would start with the real world example of the McDonald's customer that sued over the temperature of the hot coffee that they spilled in their lap. Isn't that the reason there is now the warning on the cups that the contents may be hot. In my students' eyes it's a no brainer, but exploring the ridiculous is a great motivator for 7th graders.

To begin, I would start with the Goldilocks story and begin with the question "What is just right?" I would let my students offer answers that begin to develop a set of just right criteria. Then I would introduce the McDonald's lawsuit. I would have my students do research about the temperature of coffee after it has been brewed and what ideal temperatures are for drinking warm liquids. They could also investigate the different kinds of cups are used for serving hot takeout drinks. I hope this will lead my students to develop a scientific question like "Does the type of cup influence how long it takes for a hot beverage to cool enough to drink?" Instead of using coffee, we would test with hot chocolate.

Thirty minutes of wait time for measuring temperature is too long in a 50 minute science class. There will have to be modifications in the serving size or students will need to test the temperature more freuqently, at 3-5 minute intervals. Testing at time intervals will give the students data for analyzing. At the end of the total test time, students will use their data and knowledge of heat transfer to formulate a conclusion about which beverage container retains heat the best and what the wait time is before it is safely drinkable.

I think the real world application will be the motivator for my students to see how this affects them. It may also lead to conversation and questions about design. The ability to drink all of their test samples will also be a motivating factor...seventh graders like free food.