Exploring Heat Transfer

Exploring Heat Transfer

As stated in this application’s introduction, “a good insulator is a kind of material that helps to stop heat from escaping and, therefore, keeps items such as food and drink warm longer”. Based on this description, I assumed that the materials that make the best insulators are the materials that trap the air or heat inside and do not contain holes or pores.

I set out four identical mugs, heated water in a separate container in the microwave, poured the hot water into each of the mugs, immediately covered the tops of the mugs with four different materials, and secured them with a rubber band. I chose a thin washcloth, paper towel, plastic sandwich bag, and aluminum foil to cover the mugs to trap the heat from the hot water. I assumed the aluminum foil would be the best insulator before hand because there were no holes so the heat would be trapped inside the mug. I also assumed that since my husband’s best coffee mugs are made with a metal insulation, the aluminum foil would keep the water hot the longest.

After thirty minutes, I removed the covers to check the temperature of the water in each mug. The paper towel and wash cloth both registered at 117 degrees Fahrenheit. I had trouble reading the exact results for the plastic bag cover because the wire that held the thermometer to the unit of measurements was blocking my view. It was 118, 119, or 120 degrees Fahrenheit. The result of the aluminum foil lid was 121 degrees Fahrenheit. Therefore, the aluminum foil was the best insulator, with the ziplock bag second, and the paper towel and the wash cloth were the worst insulators.

After my experiment, I resorted to my class resources to research exactly why my results were just as I suspected they would be. Buczynski (2006) explained that “heat is energy” and the amount of energy released depends on the, speed, mass, and type of particles, or molecules, in a substance. When particles vibrate with more energy, the temperature is higher (Buczynski, 2006). With this information I concluded that energy was formed when I heated the water. The energy was trapped in the cups with the lids were used for insulation. The two lids made of foil and plastic were the best insulators because they kept a higher number of particles vibrating in the cup due to the fact that there was no other place for them to be released, resulting in a higher temperature after thirty minutes. The other two insulators, the paper towel and the wash cloth, had tiny holes in them that allowed the particles to be released which reduced the number of particles which reduced the amount of energy which reduced the temperature of the water faster.

Next I explored Tillery, Enger, and, Ross (2008) for t a better understanding of heat flow. With conduction, “anytime there is a temperature difference, there is a natural transfer of heat from the region of higher temperature to the region of lower temperature” (Tillery, Enger, & Ross, 2008). This confirmed my theory that any lid that contained all of the heat or energy and kept it from leaving were the best insulators, such as the holeless foil and plastic. However, they also stated that the best insulators are materials that contain small air spaces, which keep the air molecules far apart, such as Styrofoam, glass, and wool. I am not sure the amount of air spaces located in foil or plastic, but I am sure that I would have discovered even higher temperatures if I had used one of those materials.


I would like to test other materials, such as food, to see which items will stay hot longer. When I was a waitress through, I observed that certain side items stayed hot longer. For example, the baked potato stayed hot a lot longer than the rice. Of course the outside of the potato cooled slightly, but once it was cut open with a knife, the inside was still hot and steamy.

I am assuming that the reason the potatoes stayed hot longer is because there were no "holes" for the heat energy to travel through. Therefore, the heat was trapped inside the potato because of the potato skin insulator. The pile of rice allows the heat to travel from a region of higher temperature to a region of lower temperature. This is my assumption anyway and would be a nice hypothesis to test.