Monday, February 7, 2011

Heat Transfer

In this weeks’ application inquiry, I chose four different materials to test their ability to insulate heat.  Four identical mugs were filled with the same amount of the same temperature water.  On each cup a different material was placed on the top and secured with a rubber band.  After thirty minutes the temperature of the water in each cup was recorded (see appendix for table).  The insulators I chose were faux fur, plastic bag, paper towel, and tin foil.
            I chose the fur because I thought it would be a good insulator and I chose the paper towel because I thought it would be a poor insulator (?).  {good insulator and poor conductor mean the same thing} The others I chose because I was just curious.  I also included the students in my class, I presented them with ten different materials to use as insulators and they chose four of them.  The faux fur was the best insulator; the temperature did not decrease by that many degrees.  {Since you measured the initial temperature, you could use that information here.} The next best was the plastic bag.  I was surprised that this, I did not expect the plastic bag to be a good insulator because it is so thin.  Although, it is hard for air to escape from a plastic bag so maybe that had an effect on it.  The paper towel was the third best insulator.  I did not think that the paper towel would do a good job because it was a cheap paper towel that was thin and single ply.  The worst insulator that I chose was tin foil.  This was surprising because one of the reasons people use tin foil is to cover hot dishes to keep them warm.  I am sure that using faux fur to cover lasagna would be very messy, but it would keep the lasagna the warmest.  I think a good experiment would be to find the best type of material (that would be appropriate) to cover food to keep it warm.


Other materials I might choose - saran wrap, paper, fleece, Under Armor cold gear, stocking socks - I think the best would be the Under Armor

Other materials I would want to test - any hot food products - to see which material would keep the food the warmest

How would I set this up for my classroom? I think I would set this experiment up in the same way - I think that reading the story of Goldie Locks and the Three Bears was a good introduction.  I think my students would like being able to set up their own experiment.

Learning objectives for my students - what materials are the best insulators, different types of heat transfer (conduction, convection, and radiation) -