Wednesday, September 26, 2012

Heat Transfer


I begin my guided inquiry with a question: Which material do you think would make the best insulator?  I know that a conductor allows heat to travel through it.  Therefore, an insulator is going to reduce the heat from escaping a container (Elvidge, 2012).  With this in mind, I went searching for materials in my house that may be insulators.  Since this is a guided inquiry activity, I know I can design the investigation using materials I choose to answer the teacher question (Banchi & Bell, 2008).  The materials I choose to use are foil, plastic wrap, cardboard, and parchment paper.  

 
My hypothesis in the investigation is the foil will keep the most heat in the container.  In order to test the insulator, I will use ceramic mugs.  I line up four ceramic mugs on the counter.  Then, I pour in hot water at equal amounts in each mug.  The water is at 38°C at the start of the experiment.  Quickly, I cover each mug with a different material and set a timer for thirty minutes.  At the end of the thirty minutes, I found that the parchment paper held the most heat in at 35°C.  The weakest insulator turned out to be the cardboard.  I thought this would be true since it may have absorbed some of the water vapor taking heat with it.  At the end of the activity, I continued to think about what I knew about heat and convection to justify my outcome.  Convection is the transfer of heat through liquids and gasses (Tillery, Enger, & Ross, 2008).  The foil and parchment paper had the higher temperatures, so they were insulators to keep the heat from escaping.

 Although the experiment was straight forward, I believe I could make it better.  First of all, I only used one thermometer.  I do not think my results were completely accurate due to this fact.  While I measured the temperature of one mug, another sat losing heat until I could reach it.  Also, the thermometer itself was difficult to use since it did not have measuring lines on it.  I actually needed to measure the temperature, than place it along the paper it was glued to in order to record the degree.  I am sure I lost some valuable data in this process.  Also, I did not have enough rubber bands to wrap each material onto the mug.  I did this for cardboard and parchment paper only.  The benefit of guided inquiry is the learning experience and the making sense of the results.

 This would be a great experiment for my students.  I would begin using a video from Teacher’s Domain (I will include the site in the reference section).  This video demonstrates students experimenting with materials to keep an ice cube cold.  This would launch us into our guided inquiry lab.  Students need to test materials to determine the best insulator.  I would allow students to use four cups of various materials.  For example, I will provide Styrofoam, plastic, ceramic, aluminum, etc.  Students will choose their materials and fill with hot water.  Thermometers will be available to each testing material.  Students will record the beginning temperature along with temperature readings every five minutes for a twenty-minute period.  This activity will require consistent observation and teamwork. 
 
References
Banchi, H., & Bell, R. (2008). The many levels of inquiry. Science and Children, 46(2), 26–29. Retrieved on July 8, 2012 from http://web.ebscohost.com.ezp.waldenulibrary.org/ehost/detail?sid=f218157f-411e-4b18-a5ee-9c8577f37f96%40sessionmgr11&vid=1&hid=21&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=ehh&AN=34697743

Elvidge, S. (2012). Keeping Warm or Cold: Insulation and Conduction. Retrieved on September 23, 2012 from http://www.scienceprojectideas.co.uk/keeping-warm-cold-insulation-conduction.html

Tillery, B. W., Enger, E. D., & Ross, F. C. (2008). Integrated science (4th ed.). New York: McGraw-Hill.
Teachers' Domain. (2004). Testing Insulators: Ice Cube in a Box. Retrieved on September 23, 2012 from 
http://www.teachersdomain.org/resource/phy03.sci.phys.mfe.zice/

 

2 comments:

  1. Crystal,

    I experienced similar findings. The inquiry really made me think. I originally was hypothesizing my tin foil would keep the liquid hot. Your cup illustrations are great.

    I agree, if you were only using one thermometer it would let a little time and heat transfer. The thermometer in my kit was broken. I was able to secure some from the science center at school and did all 4 cups at the same time.

    This would be a great inquiry with students.

    I explored the Teachers' Domain site you listed. It is a great resource.

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  2. I am glad I was not the only one who had a broken thermometer. I had a hard time finding one because I am still trying to buy supplies for my classrrom, but I was lucky enough to find something to measure the temperature of the water. I agree that when completing this experiment we need to use better thermomters as well as having four thermometers instead on one, that way all four cups of water could be checked at the same time.

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