This week our assignment was to identify four different materials to test as insulators. I arranged four different ceramic coffee mugs, filled each of them to the same level with boiling hot water, and then placed my four different insulators over the top, securing each with a rubber band. The four materials I chose were newspaper, plastic wrap, tin foil, and a cotton cloth. I then allowed the experiment to sit for thirty minutes. The temperatures of the four mugs did not drop low enough to be measured by the thermometer provided, so I waited another thirty minutes. At this time I was able to get the following results.
The best performing insulator that I tried was the tin foil. The tin foil kept the water at approximately 125° F (I had to estimate). The second best performer was the cotton cloth at 120° F. I was really impressed by this performance. The third best performer was the plastic wrap at 118° F. I was slightly surprised by this performance as I expected the plastic wrap to come in second due to the fact that it created such a tight seal. The final performer was the newspaper at 110° F. I had expected the top performance of the tin foil, but didn’t have any real basis for my hypothesis other than the seal. The most surprising performer for me was the cotton cloth. My guess is that the air that is trapped in the fibers possibly helped the insulation. As I understand, air can be a great insulator. I am inferring this hypothesis by the tumbler coffee cups that have an empty space of air between the stainless steel cup with the liquid and the plastic outer cup. I had anticipated the newspaper to be poor because I knew that the evaporating air would be absorbed into the paper material and allowed to escape. Evaporation often cools as it happens. I know this because of being a kayaker. When on the water, I wear neoprene-insulating layers to fight the evaporation that is happening while upright.
The methods of heat transfer that were used were conduction and radiation. Using the Amusement Park website, I know that conduction is happening because of the process of the heat transfer that is happening through the ceramic material of the mug, as well as the different materials I placed over the top of the mug. I also know that radiation is happening because of the heat transfer through the empty space in the mug, as well as between the two layers of material I placed on top of each mug. I think that convection was discouraged due to the lack of movement.
I think that a different material that I would choose to use as an insulator would be a piece of neoprene. I would choose this one because of my experiences kayaking and the insulating capabilities that I can feel. Another insulator that I might choose for my next round would be a piece of rubber. This choice would be chosen because of the rubber that I have seen to insulate different things such as wire.
Other materials to test other than water, such as hot dogs or spaghetti, may dissipate heat a different rate due to the density of the materials. It would be fun to test different materials such as a piece of steel, or a soil sample.
I think that I would set up the experiment very similar for students in a classroom. One thing I would do to help engage the students is to create a contest. I would like to know who could come up with the best insulator, but also the worst insulator. I think it would also be fun for students to bring different items from home that would contain a sample of water to see which insulates the best so we could expand our real life experience and connect this experiment to their own home.
Ultimately, I would like to students to examine what they have learned from this experiment, and begin asking questions about different items they may use at home, or see around their communities that are good heat insulators. I also think this is a great experiment to introduce the three different methods of heat transfer.
