The Heat is On Investigation

The four materials I chose to use for the investigation were aluminum foil, a cotton towel, waxed paper, and plastic wrap. I hypothesized that the aluminum foil would work the best to keep the temperature of the water the warmest. I choose aluminum foil only for the fact that I have always used it during food preparation to keep foods warm. Although, after reading the text this week, I was not sure why aluminum foil is used for that purpose since aluminum is a metal and considered a conductor not an insulator.
Upon completion of the investigation, the results showed that the cotton towel was the best insulator with the highest temperature reading of 104°F. Waxed paper was second at 102°F, then foil at 101°F, and finally plastic wrap at 100°F. Conduction is the transfer of heat energy from one molecule to another. I learned this week that materials such as wood, glass, cotton, and wool contain small air spaces. These air spaces keep molecules farther apart making it more difficult for the heat energy to move by conduction from molecule to molecule. Based on my understanding of the resources this week, I believe, the cotton towel was the best insulator due to the fact that there are small air spaces within the fabric, slowing the flow of heat energy and keeping it contained within the mug. I did not expect the cotton towel to be the best insulator and was surprised when reading the resources for this week’s assignment. Based on my own prior experiences, I thought for sure the aluminum foil would have been the material that worked the best. I am guessing that most students would also believe the same.
The only challenge that I encountered is that I had to do a lot of additional reading on the Internet to understand why aluminum foil keeps substances warm or cold. I knew that metals were good conductors of heat but never really thought about the reason of why a conductor would be a good insulator. I found a few websites that stated that the shiny side of aluminum foil reflects heat. So if you want to keep something cold put the shiny side out to reflect the heat. If you want to keep something warm, keep the shiny side in and the heat from the food reflects back inside. I cannot say for sure that this is a scientific fact because I could not find any reputable sources. However, those ideas make sense to me. I plan on doing some more inquiry investigations along with some research to try and find an explanation. Does anyone have an explanation on this issue?
I thought of an ideas while I was doing this investigation. I wanted to use wool, but did not have a sample to use in my house. However, while searching for materials, I thought of a fun experiment to use in the classroom. I would have students test different types of materials used to make socks. Specifically, socks that are marketed for winter sports to keep your feet warm. I would create a scenario where students worked for a sporting goods store or athletic clothing designer and are required to perform tests to decide which material would keep feet the warmest. Students would then create a sales pitch/poster to sell the socks based on the outcome of the experiment. It may need a little more thought but I thought it would be a fun, real-world application for students to investigate.