Investigating Heat

Heat and temperature is probably the most universal topic in the sciences. Heat can be explained in life science, earth science, physical science, etc.  In life science heat is explored as the foundation of life, when describing the impact of the sun’s energy. Chemistry defines heat and changes in temperature in physical and chemical changes.  Earth science we see the examples and effects of heat in the earth’s core, weather, and the water cycle.  In physical science heat is evident in friction, electricity, and topics involving insulators and conductors.  The list goes on and on as we envision heat as being the element that we just cannot live without.

  Investigating heat and temperature is an interesting topic for elementary aged students. Children are so excited about manipulating real thermometers and temperatures of different substances. When introducing heat and temperature, students are consumed with overwhelming curiosity and cautions.  Heat and temperature is one of those areas where everyone has had some previous experience.  Allowing student’s time to recall and reflect on their own experiences with heat and temperature will yield greater results and learning connections in the end.

            Many educators can be a little reluctant about allowing students to explore heat energy and temperature.  Due to classroom management issues and safety concerns, the reluctance is understood. On the other hand, as educators, we must begin taking risk and encouraging our students to take risk as well. On the elementary level, hot water is not as accessible.  In the past, I have used cups of ice and microwave to heat water just enough so the students can see a dramatic difference in the temperature.  The excitement on a student’s face when they actually get to see the mercury rise and fall in a thermometer is priceless.   Finding the common ground between, safety and the ultimate experience requires careful planning and student maturity considerations.

For this week’s heat experiment, I choose to test 100% cotton, wax paper, aluminum foil and plastic. My question is which material is the best insulator of heat? If I experiment to see which material is the best insulator of heat then, I predict the wax cotton would be the best insulator and wax paper would be the second best insulator. Cotton was my first choice because I immediately thought of body temperature and the clothing that we wear in the colder season.  Although cotton can be porous and some heat can escape, I still thought that it would be the better insulator.

One of the first things that I observed was that the heat was pulsating immediately in the glass that was covered with plastic. Water vapor (condensation) also appeared at a rapid rate on the plastic covered mug. The results from my first test did not support my hypothesis. When I went back to check the temperature of my samples, I found that aluminum foil did a better job of insulating the heat in the glasses. My temperature went from 110 degrees to 82 degrees with the foil covered glass.  Wax paper was the second best insulator, dropping down to 78 degrees. The plastic and cotton both dropped down to lower temperatures. Plastic decreased to 74 degrees and cotton at 70 degrees. I was quite surprised at these results. As I analyzed the data, I thought maybe the cotton that I used was very porous. The microscopic holes in the cotton allow more heat to escape from the glass container. The foil, wax paper, nor plastic had a porous surface.  I learned that aluminum foil can act as both an insulator and conductor of heat. It made me think about what material in the inner lining of some coffee mugs and an aluminum type material that is the lining of some lunch bags.  I also thought about how we use Styrofoam for dual purposes, to insulate heat and colder temperatures. I wonder if the fact that I used glass to test my materials on had an impact on my results. I wonder if the results would have been different if I had used plastic or Styrofoam containers