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Tufts OpenCourseware
Author: Fulcrum Institute Development Team

Thought Experiment - Warm Soda (~1.5 hrs.)


Einstein often examined his own understanding of physics ideas with "thought experiments." He would imagine a physics puzzle in the form of a scenario. He did not actually carry out experiments, but worked them through in his head. You, too, have ideas about how the physical world works. Use Einstein's strategy to consider a "Warm Soda" scenario to launch your thinking about heat and temperature. (Relax--this is just the start of the course; you'll revisit this same scenario later. Have fun with this.)



The Scenario

It’s a hot, still summer day. You’re having a party and soon the guests will arrive. Your friend brings over 24 cans of soda, but they’re warm and now you have four choices to cool the soda cans:

  1. Put them in the refrigerator
  2. Put them in a cooler with ice
  3. Put them in a cooler with water at 0°C
  4. Put them in a cooler with ice and pour room temperature water over the ice

Spend 30 minutes taking notes about the temperature change and heat transfer that you think will occur in each case.

  • Sketch graphs showing temperature change over thirty minutes at two locations: in a can of soda, and in the environment (i.e. the air inside the refrigerator in case 1, the ice in case 2, the water in cases 3 and 4). Printable graph paper is provided.
  • Draw a diagram, showing where and by what process(es) heat transfer is occurring in the system.
  • Imagine you could zoom in on the system until it is magnified a billion times and you "see" the materials at a particle scale. In each case, as heat is transferred from the warm soda to its surroundings, what changes occur?

Use your notes to write a report. Describe the heat flow and temperature change that occur in each case. Give as much detail as possible to explain the process using both a macroscopic and a particle model. Out of the four cases you explained, which is the fastest way to cool the soda cans? Explain your choice.


ost your Thought Experiment report in your Warm Soda Forum by Friday. (There's no need to discuss these reports.) If you'd like to post diagrams made in Word or PowerPoint, please type your name on them and attach them, but include the main text of your Thought Experiment in the body of the post.

NOTE: This thought experiment is an opportunity for self assessment. You’ve just begun your study of heat transfer and temperature change and this thought experiment may seem daunting now. It's purpose is to give you a snapshot of your thinking as you begin your coursework. As you pursue your studies, return to this Thought Experiment and keep notes as new insights and questions arise. At the end of the course, you’ll have a chance to rework the thought experiment and see how your thinking has changed.