Discussion of the section on thermal equilibrium
Here are some things to do to finish this section. You are asked as a group to send us a discussion of at least 2 of the following questions.  We encourage you to discuss them all, but we ask for an email response to only two of them.  Remember go to this page for some general guidance on what we want you to include in your discussions.
  1. The wind certainly makes you feel cold. How does it affect the thermometer reading? Consider a thermometer in your room that is reading 22oC (72oF).  If you turn a small electric fan on and point it at the thermometer - or even fan it vigorously with a piece of paper folded into a fan shape - how will it affect the reading and why? Discuss the respects in which you differ from a thermometer that are relevant to your answer (after all, you both have red noses!).
  2. Here are some ways to deliver energy, and some estimates of what they cost. Use this data to determine what a Joule costs, each way. If energy was completely easy to convert from one form to another, the cost for 1,000,000 J would be the same for each way. Think about and comment on why the cost varies the way it does.
  3. Item   Energy Content    Price    Cost for 1,000,000 J 
    Lift 1000 bricks 1 meter 10,000 J $10.00 *  
    A pound of steak 5,000,000 J   $8.00  
    A ton of coal 22,000,000,000 J $35.00   
    A barrel of oil 6,000,000,000 J  $18.00  
    1 Kilowatt-hour of electricity 3,600,000 J    $0.08  
    1 Therm of natural gas 105,500,000 J    $0.30  
    1 tsp sugar (15 Kilocalories) 63,000 J    $0.004 **  
    1 gallon gasoline 135,000,000 J    $1.899 ***  
    Energy doesn't change, but prices do! The numbers in the table were reasonable values in the spring of 2001.

    *Assuming the person lifting the bricks is being paid $10.00/hour.
    **Assuming 453 teaspoonsful in a $1.89 bag of sugar.
    ***Including all sorts of taxes.

    You might prefer to do this exercise using Excel. There is a worksheet energy.xls that has the numbers already entered for you. There also is a page on using Excel

  4. Room temperature inside your house is probably about 72oF.  Now consider other locations, such as on the porch, or in the attic.  What does "thermal equilibrium" mean in these other environments?  And how will an object taken from inside your house be affected when it is moved into one of those other environments?
Please send us your discussions of two of these questions. Don't forget to tell us who is in the group.

In addition to sending your discussion of the questions, please write something in your journal about this question:
Have you been working in a group, solo, or both?
If you have been working in a group as well as on your own, please comment on the differences between working on this CD course with a group vs. working on it alone. What have been the benefits? Drawbacks?
If you have been working only in a group or only by yourself, please comment on the potential benefit you might envision working in another arrangement with our materials.

If there is something that you don't understand about thermal equilibrium, Ask us!

This is the end of this section. (Check this box )   The next section is about thermal expansion.