In Hot Water

We have been asked to conduct an experiment comparing the insulating abilities of four different materials. I went with materials that keep people warm in these cold and blustery months. I chose wool, traditionally used for centuries to make clothing. I selected a synthetic felt which is not woven but tightly matted acrylic and polyester. Being thick, I thought it would hold in the heat well. The next material I chose was fleece. We have use fleece to make throw blankets to snuggle on the couch with. The last material I selected was not a fabric but a foil, aluminum foil. I wanted to branch away from textiles and use an insulator commonly used to keep wood warm.

I selected four mugs identical in size, shape, and composition.  Into each mug, I poured one cup of boiling water; measured and recorded the temperature; cover the cup’s opening with one of the selected insulators; and then secured it with a rubber band. After waiting the designated 30 minutes, I uncovered each container; measured and recorded the temperature; then recovered the each mug. I calculated the drop in temperature for each of the four cups as I waited an additional 30 minutes before taking the temperatures again.

I found the water temperature in both the wool and the felt covered mugs dropped 91° total, within two, 30 minute testing periods. The aluminum foil covered mug dropped 94°, while the fleece covered mug lost 96° in the one hour period. I thought the wool and felt would come out on top, but was surprised the foil held in more heat than the fleece.

 I do not believe the data I collected to be reliable enough to draw an accurate conclusion. I would want to perform the experiment several times over to gather more data. My experiment did however, seemed to show wool and felt being the best insulators. They were able to trap more of the radiant heat inside the mug. Less heat energy could escape than in the other two mugs resulting in a smaller change in temperature.

I think if I were to conduct this experiment again, I would choose different insulating materials to test. I would consider using a hot pad/oven mitt. We use oven mitts to protect our hands for being burned when removing hot objects from the oven. They must make good insulators. I would also use a sheet of Styrofoam. We use Styrofoam often for containing hot drinks because the material prevents our hands from burning. It retards the conduction of heat energy. The heat of the contents does not transfer to the cup and then to our hands, easily.  I would also try cardboard like the sleeves put on coffee cups in fancy coffee joints. Surely, coffee companies tested different materials to find the most efficient choice for protecting the hands or their customers.

I could use this experiment to help my students understand diffusion, the movement of particles from an area of high concentration to an area of lower concentration. Diffusion can be a difficult concept to grasp so using a variety of examples is beneficial. Additionally, understanding the movement of heat energy from high concentration to low will better prepare my students for physical science next year.

All in all, I would say this experiment was a success for me.